Motion sickness; motion sickness–associated nausea/vomiting:
Oral:
Immediate release: 50 to 100 mg every 4 to 6 hours (maximum: 400 mg/day).
Immediate-release/sustained-release combination [Canadian product]: 100 mg every 8 to 12 hours (maximum: 300 mg/day).
Rectal [Canadian product]: 50 to 100 mg every 6 to 8 hours as necessary.
IM, IV: 50 mg every 4 hours; may increase to 100 mg every 4 hours if needed.
Nausea and vomiting, pregnancy associated, severe or refractory (alternative agent) (off-label use): Note: May be considered as a component of combination therapy when symptoms persist following initial pharmacologic therapy. Combined use with doxylamine (or other H1 antagonist) may increase adverse reactions (Ref).
Oral: 25 to 50 mg every 4 to 6 hours as needed; maximum: 300 mg per day. Note: Maximum of 200 mg per day if patient is also taking doxylamine (Ref).
IV: 50 mg administered over 20 minutes every 4 to 6 hours as needed; maximum: 300 mg per day. Note: Maximum: 200 mg per day if patient is also taking doxylamine (Ref).
Rectal [Canadian product]: 50 mg every 4 to 6 hours as needed; maximum: 300 mg per day. Note: Maximum: 200 mg per day if patient is also taking doxylamine (Ref).
Postoperative nausea and vomiting:
Oral [Canadian labeled indication]: 50 to 100 mg prior to procedure, then 50 to 100 mg post-procedure; repeat as necessary (maximum: 400 mg/day).
IM, IV [Canadian product]: 50 mg prior to treatment, then 50 mg post-procedure; repeat as necessary (maximum: 400 mg/day).
Radiation sickness:
IM, IV [Canadian labeled indication]: 50 to 100 mg 30 to 60 minutes prior to treatment, then 50 mg at 90 minutes after treatment, followed by 50 mg at 3 hours after treatment. Repeat dose as necessary (maximum: 400 mg/day).
Rectal [Canadian product]: 50 to 100 mg 30 to 60 minutes prior to treatment; repeat as necessary (maximum: 400 mg/day).
Vertigo, acute episodes:
Note: Reserve use for symptomatic relief of episodes lasting several hours to days (maximum duration: 3 days); chronic use may impede adaptation and recovery (Ref).
Oral:
Immediate release: 50 mg every 4 to 6 hours (Ref). The manufacturer's labeling recommends a maximum of 400 mg/day; however, some experts do not recommend doses greater than 300 mg/day (Ref).
Immediate-release/sustained-release combination [Canadian product]: 100 mg every 8 to 12 hours (maximum: 300 mg/day).
Rectal [Canadian product]: 50 to 100 mg every 6 to 8 hours.
IM, IV: 50 mg every 4 to 6 hours (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
The renal dosing recommendations are based upon the best available evidence and clinical expertise. Senior Editorial Team: Bruce Mueller, PharmD, FCCP, FASN, FNKF; Jason A. Roberts, PhD, BPharm (Hons), B App Sc, FSHP, FISAC; Michael Heung, MD, MS.
Note: There are no data describing dimenhydrinate pharmacokinetics in kidney impairment; the following recommendations are based upon limited pharmacokinetic data described only in patients with normal kidney function receiving dimenhydrinate or diphenhydramine (diphenhydramine is produced from dimenhydrinate) (Ref).
Altered kidney function: IM, IV, Oral, Rectal: No dosage adjustment necessary for any degree of kidney impairment (Ref).
Augmented renal clearance (measured urinary CrCl ≥130 mL/minute/1.73 m2): Augmented renal clearance (ARC) is a condition that occurs in certain critically ill patients without organ dysfunction and with normal serum creatinine concentrations. Younger patients (<55 years of age) admitted post trauma or major surgery are at highest risk for ARC, as well as those with sepsis, burns, or hematologic malignancies. An 8- to 24-hour measured urinary CrCl is necessary to identify these patients (Ref).
IM, IV, Oral, Rectal: No dosage adjustment necessary (Ref).
Hemodialysis, intermittent (thrice weekly): Unlikely to be significantly dialyzable (large Vd, high protein binding): IM, IV, Oral, Rectal: No dosage adjustment necessary (Ref).
Peritoneal dialysis: Unlikely to be significantly dialyzable (large Vd, high protein binding): IM, IV, Oral, Rectal: No dosage adjustment necessary (Ref).
CRRT: IM, IV, Oral, Rectal: No dosage adjustment necessary (Ref).
PIRRT (eg, sustained, low-efficiency diafiltration): IM, IV, Oral, Rectal: No dosage adjustment necessary (Ref).
There are no dosage adjustments provided in the manufacturer's labeling; use with caution.
Avoid use (Ref).
(For additional information see "Dimenhydrinate: Pediatric drug information")
Motion sickness, nausea/vomiting, or vertigo, prophylaxis:
Oral products:
Fixed dose: Administer initial dose 30 to 60 minutes before travel/activity
Children ≥2 to <6 years: Oral: 12.5 to 25 mg every 6 to 8 hours; maximum daily dose: 75 mg/24 hours
Children ≥6 years to <12 years: Oral: 25 to 50 mg every 6 to 8 hours; maximum daily dose: 150 mg/24 hours
Children ≥12 years and Adolescents: Oral: 50 to 100 mg every 4 to 6 hours; maximum daily dose: 400 mg/24 hours
Weight-based dosing: Children 2 to 12 years: Oral: Limited data available: 1 to 1.5 mg/kg/dose every 6 hours; maximum dose: 25 mg/dose. First dose should be administered 60 minutes prior to travel (Ref).
Parenteral products: IM:
Weight-based dosing: Infants, Children, and Adolescents: IM: 1.25 mg/kg/dose 4 times daily; maximum daily dose: 300 mg/day
BSA-based dosing: Infants, Children, and Adolescents: IM: 37.5 mg/m2/dose 4 times daily; maximum daily dose: 300 mg/day
Canadian labeling: Rectal suppository [Canadian product]:
Children 2 to ≤5 years: Rectal: 12.5 mg to 25 mg once; if more doses needed, contact health care provider
Children 6 to 7 years: Rectal: 12.5 to 25 mg every 8 to 12 hours as needed
Children 8 to 11 years: Rectal: 25 to 50 mg every 8 to 12 hours as needed
Children ≥12 years and Adolescents: Rectal: 50 mg every 8 to 12 hours as needed
Postoperative nausea and vomiting (PONV): Limited data available:
Prevention: Infants, Children, and Adolescents: IV: 0.5 mg/kg/dose; maximum dose: 25 mg/dose (Ref)
Treatment:
Weight-directed: Infants, Children, and Adolescents: IV: 0.5 mg/kg/dose; maximum dose: 25 mg/dose; for treatment of PONV, use only if prophylaxis fails and dimenhydrinate is from a different pharmacologic class than prophylactic drug (Ref)
Fixed dose (Ref):
Children 6 to 7 years: IM, IV: 15 to 25 mg two or three times daily
Children 8 to 12 years: IM, IV: 25 to 50 mg two or three times daily
Children ≥12 years and Adolescents: IM, IV: 50 mg two or three times daily
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer's labeling.
There are no dosage adjustments provided in the manufacturer's labeling; use with caution.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Frequency not defined.
Cardiovascular: Tachycardia
Central nervous system: Dizziness, drowsiness, excitement, headache, insomnia, lassitude, nervousness, restlessness
Dermatologic: Skin rash
Gastrointestinal: Anorexia, epigastric distress, nausea, xerostomia
Genitourinary: Dysuria
Ophthalmic: Blurred vision
Respiratory: Thickening of bronchial secretions
Hypersensitivity to dimenhydrinate or any component of the formulation; neonates (injection contains benzyl alcohol)
Canadian labeling: Additional contraindications (not in US labeling): Hypersensitivity to dimenhydrinate, its components (diphenhydramine or 8-chlorotheophylline) or any component of the formulation; concurrent use of or use within 14 days following therapy with a monoamine oxidase inhibitor; narrow angle glaucoma; chronic pulmonary disease; prostatic hypertrophy; patients <2 years of age
Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Concerns related to adverse effects:
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving). Other CNS effects which may be observed, particularly at higher dosages include euphoria, hallucinations, confusion, temporary amnesia and paranoia.
• Dermatologic reactions: Rare cases of serious skin reactions (eg, Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme) have been reported.
Disease-related concerns:
• Cardiovascular disease: Use with caution in patients with cardiovascular disease (including arrhythmias, hypertension and ischemic heart disease).
• Hepatic impairment: Use with caution in patients with hepatic impairment.
• Increased intraocular pressure/glaucoma: Use with caution in patients with increased intraocular pressure or angle-closure glaucoma.
• Prostatic hyperplasia/urinary obstruction: Use with caution in patients with prostatic hyperplasia and/or GU obstruction.
• Pyloroduodenal obstruction: Use with caution in patients with pyloroduodenal obstruction (including stenotic peptic ulcer).
• Respiratory disease: Use with caution in patients with a history of asthma or lower respiratory tract symptoms.
• Seizures: Use with caution in patients with seizure disorders.
• Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.
Concurrent drug therapy issues:
• Antibiotics: Use caution if used in conjunction with antibiotics that have the potential to cause ototoxicity. Dimenhydrinate may mask symptoms of ototoxicity.
Special populations:
• Older adult: Use with caution in older adults; may be more sensitive to adverse effects.
• Pediatric: Antihistamines may cause excitation in young children. Not for OTC use in children <2 years of age.
Dosage form specific issues:
• Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity ("gasping syndrome") in neonates; the "gasping syndrome" consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension and cardiovascular collapse (AAP 1997; CDC 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer's labeling.
• Parenteral formulations: Do not inject intra-arterially.
• Phenylalanine: Some products may contain phenylalanine.
• Polysorbate 80: Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson 2002; Lucente 2000; Shelley 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade 1986; CDC 1984). See manufacturer's labeling.
• Propylene glycol: Some dosage forms may contain propylene glycol; large amounts are potentially toxic and have been associated with hyperosmolality, lactic acidosis, seizures and respiratory depression; use caution (AAP 1997; Zar 2007). See manufacturer's labeling.
Other warnings/precautions:
• Abuse/withdrawal: Has abuse potential due to its hallucinogenic and euphoric effects; discontinuation after chronic abuse may lead to withdrawal symptoms (eg, lethargy, agitation, hostility, hallucinations, confusion, aggression, nausea/vomiting).
Some dosage forms may contain propylene glycol; in neonates large amounts of propylene glycol delivered orally, intravenously (eg, >3,000 mg/day), or topically have been associated with potentially fatal toxicities which can include metabolic acidosis, seizures, renal failure, and CNS depression; toxicities have also been reported in children and adults including hyperosmolality, lactic acidosis, seizures, and respiratory depression; use caution (AAP 1997; Shehab 2009).
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Solution, Injection:
Generic: 50 mg/mL (1 mL)
Tablet, Oral:
Dramamine: 50 mg
Driminate: 50 mg
Driminate: 50 mg [scored]
GoodSense Motion Sickness: 50 mg [DSC] [scored]
Tablet Chewable, Oral:
Dramamine: 50 mg
May be product dependent
Solution (dimenhyDRINATE Injection)
50 mg/mL (per mL): $15.77
Tablets (Driminate Oral)
50 mg (per each): $0.08
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Injection:
Gravol: 50 mg/mL (1 mL, 5 mL)
Generic: 10 mg/mL (5 mL); 50 mg/mL (1 mL, 5 mL)
Suppository, Rectal:
Gravol Comfort Shaped Suppository: 100 mg
Gravol Kids Comfort Shaped Suppository: 25 mg
Oral: To prevent motion sickness, administer 30 to 60 minutes prior to exposure.
Solution for injection:
IM: Administer undiluted
IV: Dilute and inject over 2 minutes. When using for pregnancy-associated nausea and vomiting, administer dose (diluted in 50 mL of normal saline) over 20 minutes (Ref).
Rectal suppository [Canadian product]: To prevent motion sickness, nausea/vomiting, or vertigo, administer 30 minutes prior to event.
Oral: Motion sickness: Administer 30 to 60 minutes before travel/activity that causes motion sickness
Parenteral:
IM: Administer undiluted
IV: Although not recommended (per manufacturer), may further dilute and administer IV over 2 minutes; do not inject intra-arterially (Ref)
Rectal: Rectal suppository [Canadian product]: Children ≥2 years and Adolescents: Remove outer wrapper and smooth any edges (for comfort); may need to cut suppository to achieve appropriate dose. To prevent motion sickness, nausea/vomiting, or vertigo, administer 30 minutes prior to event.
US labeling: Motion sickness: Treatment and prevention of nausea, vertigo, and vomiting associated with motion sickness.
Canadian labeling: Nausea, vomiting and/or vertigo: Treatment and prevention of nausea, vomiting and/or vertigo associated with motion sickness, radiation sickness, postoperative recovery, use of other drugs, Ménière disease and other labyrinthine disturbances.
Nausea and vomiting, pregnancy-associated, severe or refractory; Vertigo, acute episodes
DimenhyDRINATE may be confused with diphenhydrAMINE
Dramamine (dimenhydrinate) may be confused with Dramamine (ginger root), Dramamine (meclizine)
Beers Criteria: Dimenhydrinate, a first-generation antihistamine, is identified in the Beers Criteria as a potentially inappropriate medication to be avoided in patients 65 years and older (independent of diagnosis or condition) due to its potent anticholinergic properties resulting in increased risk of confusion, dry mouth, constipation, and other anticholinergic effects or toxicity; use should also be avoided due to reduced clearance with advanced age and tolerance associated with use as a hypnotic. Exposure to concurrent anticholinergic drugs also increases risk of falls, delirium, and dementia; consider total anticholinergic burden when conducting medication reviews (Beers Criteria [AGS 2023]).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Acetylcholinesterase Inhibitors: May decrease therapeutic effects of Agents with Clinically Relevant Anticholinergic Effects. Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Acetylcholinesterase Inhibitors. Risk C: Monitor
Aclidinium: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Acrivastine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Acrivastine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Alcohol (Ethyl): CNS Depressants may increase CNS depressant effects of Alcohol (Ethyl). Risk C: Monitor
Alizapride: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Amantadine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Amezinium: Antihistamines may increase stimulatory effects of Amezinium. Risk C: Monitor
Amisulpride (Oral): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Articaine: May increase CNS depressant effects of CNS Depressants. Management: Consider reducing the dose of articaine if possible when used in patients who are also receiving CNS depressants. Monitor for excessive CNS depressant effects with any combined use. Risk D: Consider Therapy Modification
Azelastine (Nasal): May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Benperidol: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Benperidol. Risk C: Monitor
Benperidol: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Benztropine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Benztropine. Risk C: Monitor
Benzylpenicilloyl Polylysine: Coadministration of Antihistamines and Benzylpenicilloyl Polylysine may alter diagnostic results. Management: Suspend systemic H1 antagonists for benzylpenicilloyl-polylysine skin testing and delay testing until systemic antihistaminic effects have dissipated. A histamine skin test may be used to assess persistent antihistaminic effects. Risk D: Consider Therapy Modification
Betahistine: Antihistamines may decrease therapeutic effects of Betahistine. Betahistine may decrease therapeutic effects of Antihistamines. Risk C: Monitor
Biperiden: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Biperiden. Risk C: Monitor
Blonanserin: CNS Depressants may increase CNS depressant effects of Blonanserin. Management: Use caution if coadministering blonanserin and CNS depressants; dose reduction of the other CNS depressant may be required. Strong CNS depressants should not be coadministered with blonanserin. Risk D: Consider Therapy Modification
Bornaprine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Bornaprine. Risk C: Monitor
Botulinum Toxin-Containing Products: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Brexanolone: CNS Depressants may increase CNS depressant effects of Brexanolone. Risk C: Monitor
Brimonidine (Topical): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Bromopride: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Bromperidol: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Buclizine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Buclizine. Risk C: Monitor
Buclizine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Buprenorphine: CNS Depressants may increase CNS depressant effects of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine at lower doses in patients already receiving CNS depressants. Risk D: Consider Therapy Modification
BusPIRone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Cannabinoid-Containing Products: Agents with Clinically Relevant Anticholinergic Effects may increase tachycardic effects of Cannabinoid-Containing Products. Risk C: Monitor
Cannabinoid-Containing Products: CNS Depressants may increase CNS depressant effects of Cannabinoid-Containing Products. Risk C: Monitor
Certoparin: Antihistamines may increase therapeutic effects of Certoparin. Risk C: Monitor
Cetirizine (Systemic): May increase CNS depressant effects of CNS Depressants. Management: Consider avoiding this combination if possible. If required, monitor for excessive sedation or CNS depression, limit the dose and duration of combination therapy, and consider CNS depressant dose reductions. Risk D: Consider Therapy Modification
Chloral Hydrate/Chloral Betaine: CNS Depressants may increase CNS depressant effects of Chloral Hydrate/Chloral Betaine. Management: Consider alternatives to the use of chloral hydrate or chloral betaine and additional CNS depressants. If combined, consider a dose reduction of either agent and monitor closely for enhanced CNS depressive effects. Risk D: Consider Therapy Modification
Chlormethiazole: May increase CNS depressant effects of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Risk D: Consider Therapy Modification
Chlorphenesin Carbamate: May increase adverse/toxic effects of CNS Depressants. Risk C: Monitor
Chlorprothixene: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Chlorprothixene. Risk C: Monitor
Cimetropium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Cimetropium. Risk X: Avoid
CloZAPine: Agents with Clinically Relevant Anticholinergic Effects may increase constipating effects of CloZAPine. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for signs and symptoms of gastrointestinal hypomotility and consider prophylactic laxative treatment. Risk D: Consider Therapy Modification
CNS Depressants: May increase adverse/toxic effects of CNS Depressants. Risk C: Monitor
Cyclizine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Dantrolene: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Daridorexant: May increase CNS depressant effects of CNS Depressants. Management: Dose reduction of daridorexant and/or any other CNS depressant may be necessary. Use of daridorexant with alcohol is not recommended, and the use of daridorexant with any other drug to treat insomnia is not recommended. Risk D: Consider Therapy Modification
Darifenacin: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Darifenacin. Risk C: Monitor
DexmedeTOMIDine: CNS Depressants may increase CNS depressant effects of DexmedeTOMIDine. Management: Monitor for increased CNS depression during coadministration of dexmedetomidine and CNS depressants, and consider dose reductions of either agent to avoid excessive CNS depression. Risk D: Consider Therapy Modification
Dicyclomine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Dicyclomine. Risk C: Monitor
Difelikefalin: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Difenoxin: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Dihydralazine: CNS Depressants may increase hypotensive effects of Dihydralazine. Risk C: Monitor
Dimethindene (Systemic): Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Dimethindene (Systemic). Risk C: Monitor
Dimethindene (Topical): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Dothiepin: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Doxylamine: CNS Depressants may increase CNS depressant effects of Doxylamine. Risk C: Monitor
DroNABinol: Agents with Clinically Relevant Anticholinergic Effects may increase tachycardic effects of DroNABinol. Risk X: Avoid
DroPERidol: May increase CNS depressant effects of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (eg, opioids, barbiturates) with concomitant use. Risk D: Consider Therapy Modification
Eluxadoline: Agents with Clinically Relevant Anticholinergic Effects may increase constipating effects of Eluxadoline. Risk X: Avoid
Emedastine (Systemic): May increase CNS depressant effects of CNS Depressants. Management: Consider avoiding this combination if possible. If required, monitor for excessive sedation or CNS depression, limit the dose and duration of combination therapy, and consider CNS depressant dose reductions. Risk C: Monitor
Entacapone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Esketamine (Nasal): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Fesoterodine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Fesoterodine. Risk C: Monitor
Flunarizine: CNS Depressants may increase CNS depressant effects of Flunarizine. Risk X: Avoid
Flunitrazepam: CNS Depressants may increase CNS depressant effects of Flunitrazepam. Management: Reduce the dose of CNS depressants when combined with flunitrazepam and monitor patients for evidence of CNS depression (eg, sedation, respiratory depression). Use non-CNS depressant alternatives when available. Risk D: Consider Therapy Modification
FluPHENAZine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Gastrointestinal Agents (Prokinetic): Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Gastrointestinal Agents (Prokinetic). Risk C: Monitor
Gepotidacin: May decrease anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Glucagon: Agents with Clinically Relevant Anticholinergic Effects may increase adverse/toxic effects of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Risk C: Monitor
Glycopyrrolate (Oral Inhalation): Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Glycopyrrolate (Oral Inhalation). Risk X: Avoid
Glycopyrrolate (Systemic): Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Glycopyrrolate (Systemic). Risk C: Monitor
Glycopyrronium (Topical): May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Hyaluronidase: Antihistamines may decrease therapeutic effects of Hyaluronidase. Risk C: Monitor
HydrOXYzine: May increase CNS depressant effects of CNS Depressants. Management: Consider a decrease in the CNS depressant dose, as appropriate, when used together with hydroxyzine. Increase monitoring of signs/symptoms of CNS depression in any patient receiving hydroxyzine together with another CNS depressant. Risk D: Consider Therapy Modification
Ipratropium (Nasal): May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Ipratropium (Oral Inhalation): May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Itopride: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Itopride. Risk C: Monitor
Ixabepilone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Kava Kava: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Ketotifen (Systemic): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Kratom: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Lemborexant: May increase CNS depressant effects of CNS Depressants. Management: Dosage adjustments of lemborexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive CNS depressant effects. Close monitoring for CNS depressant effects is necessary. Risk D: Consider Therapy Modification
Levocetirizine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Levosulpiride: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Levosulpiride. Risk X: Avoid
Lisuride: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Lofepramine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Lofexidine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Loxapine: CNS Depressants may increase CNS depressant effects of Loxapine. Management: Consider reducing the dose of CNS depressants administered concomitantly with loxapine due to an increased risk of respiratory depression, sedation, hypotension, and syncope. Risk D: Consider Therapy Modification
Magnesium Sulfate: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Maprotiline: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Maprotiline. Risk C: Monitor
Melitracen [INT]: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Melperone: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Mequitazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Metergoline: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Methotrimeprazine: CNS Depressants may increase CNS depressant effects of Methotrimeprazine. Methotrimeprazine may increase CNS depressant effects of CNS Depressants. Management: Reduce the usual dose of CNS depressants by 50% if starting methotrimeprazine until the dose of methotrimeprazine is stable. Monitor patient closely for evidence of CNS depression. Risk D: Consider Therapy Modification
Methoxyflurane: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Methscopolamine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Methscopolamine. Risk C: Monitor
Metoclopramide: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
MetyroSINE: CNS Depressants may increase sedative effects of MetyroSINE. Risk C: Monitor
Minocycline (Systemic): May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Mirabegron: Agents with Clinically Relevant Anticholinergic Effects may increase adverse/toxic effects of Mirabegron. Risk C: Monitor
Moxonidine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Nabilone: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Nalfurafine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Nitroglycerin: Agents with Clinically Relevant Anticholinergic Effects may decrease absorption of Nitroglycerin. Specifically, anticholinergic agents may decrease the dissolution of sublingual nitroglycerin tablets, possibly impairing or slowing nitroglycerin absorption. Risk C: Monitor
Noscapine: CNS Depressants may increase adverse/toxic effects of Noscapine. Risk X: Avoid
OLANZapine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of OLANZapine. Risk C: Monitor
Olopatadine (Nasal): May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Opicapone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Opioid Agonists: CNS Depressants may increase CNS depressant effects of Opioid Agonists. Management: Avoid concomitant use of opioid agonists and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Risk D: Consider Therapy Modification
Opipramol: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Opipramol: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Orphenadrine: CNS Depressants may increase CNS depressant effects of Orphenadrine. Risk X: Avoid
Oxatomide: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Oxomemazine: May increase CNS depressant effects of CNS Depressants. Risk X: Avoid
Oxybate Salt Products: CNS Depressants may increase CNS depressant effects of Oxybate Salt Products. Management: Consider alternatives to this combination when possible. If combined, dose reduction or discontinuation of one or more CNS depressants (including the oxybate salt product) should be considered. Interrupt oxybate salt treatment during short-term opioid use Risk D: Consider Therapy Modification
OxyBUTYnin: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of OxyBUTYnin. Risk C: Monitor
OxyCODONE: CNS Depressants may increase CNS depressant effects of OxyCODONE. Management: Avoid concomitant use of oxycodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Risk D: Consider Therapy Modification
Paliperidone: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Paraldehyde: CNS Depressants may increase CNS depressant effects of Paraldehyde. Risk X: Avoid
Perampanel: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Perazine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Periciazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Perphenazine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Perphenazine. Risk C: Monitor
Pipamperone: May increase adverse/toxic effects of CNS Depressants. Risk C: Monitor
Piribedil: CNS Depressants may increase CNS depressant effects of Piribedil. Risk C: Monitor
Pitolisant: Antihistamines may decrease therapeutic effects of Pitolisant. Risk X: Avoid
Pizotifen: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Potassium Chloride: Agents with Clinically Relevant Anticholinergic Effects may increase ulcerogenic effects of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Risk X: Avoid
Potassium Citrate: Agents with Clinically Relevant Anticholinergic Effects may increase ulcerogenic effects of Potassium Citrate. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium citrate. Risk X: Avoid
Pramipexole: CNS Depressants may increase sedative effects of Pramipexole. Risk C: Monitor
Pramlintide: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. These effects are specific to the GI tract. Risk X: Avoid
Procarbazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Promethazine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Promethazine. Risk C: Monitor
Propantheline: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Propantheline. Risk C: Monitor
Propiverine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
QuiNIDine: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk C: Monitor
Ramosetron: Agents with Clinically Relevant Anticholinergic Effects may increase constipating effects of Ramosetron. Risk C: Monitor
Revefenacin: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Revefenacin. Risk X: Avoid
Rilmenidine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Rivastigmine: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Rivastigmine. Rivastigmine may decrease therapeutic effects of Agents with Clinically Relevant Anticholinergic Effects. Management: Use of rivastigmine with an anticholinergic agent is not recommended unless clinically necessary. If the combination is necessary, monitor for reduced anticholinergic effects. Risk D: Consider Therapy Modification
Ropeginterferon Alfa-2b: CNS Depressants may increase adverse/toxic effects of Ropeginterferon Alfa-2b. Specifically, the risk of neuropsychiatric adverse effects may be increased. Management: Avoid coadministration of ropeginterferon alfa-2b and other CNS depressants. If this combination cannot be avoided, monitor patients for neuropsychiatric adverse effects (eg, depression, suicidal ideation, aggression, mania). Risk D: Consider Therapy Modification
ROPINIRole: CNS Depressants may increase sedative effects of ROPINIRole. Risk C: Monitor
Rotigotine: CNS Depressants may increase sedative effects of Rotigotine. Risk C: Monitor
Scopolamine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Scopolamine. Risk C: Monitor
Secretin: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Secretin. Management: Avoid concomitant use of anticholinergic agents and secretin. Discontinue anticholinergic agents at least 5 half-lives prior to administration of secretin. Risk D: Consider Therapy Modification
Sofpironium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Sofpironium. Risk X: Avoid
Suvorexant: CNS Depressants may increase CNS depressant effects of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Risk D: Consider Therapy Modification
Thalidomide: CNS Depressants may increase CNS depressant effects of Thalidomide. Risk X: Avoid
Thiazide and Thiazide-Like Diuretics: Agents with Clinically Relevant Anticholinergic Effects may increase serum concentration of Thiazide and Thiazide-Like Diuretics. Risk C: Monitor
Thiothixene: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Thiothixene. Risk C: Monitor
Tiapride: Agents with Clinically Relevant Anticholinergic Effects may decrease therapeutic effects of Tiapride. Risk C: Monitor
Tiotropium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Tiotropium. Risk X: Avoid
Tolterodine: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Tolterodine. Risk C: Monitor
Topiramate: Agents with Clinically Relevant Anticholinergic Effects may increase adverse/toxic effects of Topiramate. Risk C: Monitor
Tranylcypromine: May increase anticholinergic effects of Antihistamines, First Generation. Risk X: Avoid
Tricyclic Antidepressants: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Tricyclic Antidepressants. Risk C: Monitor
Trimeprazine: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Trimethobenzamide: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Trimethobenzamide. Risk C: Monitor
Trospium: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Trospium. Risk C: Monitor
Umeclidinium: May increase anticholinergic effects of Agents with Clinically Relevant Anticholinergic Effects. Risk X: Avoid
Valerian: May increase CNS depressant effects of CNS Depressants. Risk C: Monitor
Zolpidem: CNS Depressants may increase CNS depressant effects of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Risk D: Consider Therapy Modification
Zuclopenthixol: Agents with Clinically Relevant Anticholinergic Effects may increase anticholinergic effects of Zuclopenthixol. Risk C: Monitor
Zuranolone: May increase CNS depressant effects of CNS Depressants. Management: Consider alternatives to the use of zuranolone with other CNS depressants or alcohol. If combined, consider a zuranolone dose reduction and monitor patients closely for increased CNS depressant effects. Risk D: Consider Therapy Modification
Dimenhydrinate crosses the placenta. The risk of fetal abnormalities was not increased following maternal use of dimenhydrinate during any trimester of pregnancy.
Dimenhydrinate may be used for the adjunctive treatment of pregnancy-associated nausea and vomiting (ACOG 2018; SOGC [Campbell 2016]). Dimenhydrinate may have an oxytocic effect if used during labor.
Dimenhydrinate is present in breast milk.
Drowsiness and irritability have been reported in breastfed infants exposed to antihistamines; of these effects, irritability was reported in one infant exposed to dimenhydrinate (Ito 1993). The manufacturer recommends that the decision to continue or discontinue breastfeeding during therapy should take into account the risk of exposure to the infant and the benefits of treatment to the mother. In general, if a breastfed infant is exposed to a first generation antihistamine via breast milk, they should be monitored for irritability or drowsiness (Butler 2014).
Antihistamines may decrease maternal serum prolactin concentrations when administered prior to the establishment of lactation (Messinis 1985).
Tablets may be taken with food or water. Some products may contain phenylalanine.
Competes with histamine for H1-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract; blocks chemoreceptor trigger zone, diminishes vestibular stimulation, and depresses labyrinthine function through its central anticholinergic activity
Note: Dimenhydrinate is a salt of two drugs: Diphenhydramine (53% to 55.5%) and 8-chlorotheophylline (44% to 47%). Refer to DiphenhydrAMINE (Systemic) monograph.
Onset of action: Antiemetic: IV: immediate; IM: 20 to 30 minutes; Oral: 15 to 30 minutes (Gravol Canadian labeling 2016).
Duration: Oral: 4 to 6 hours (Gravol Canadian labeling 2016).
Absorption: Well absorbed.
Distribution: Oral: 3 to 4 L/kg (Gravol Canadian labeling 2016).
Protein binding: Oral: 70% to 85% (Gravol Canadian labeling 2016).
Metabolism: Extensive in the liver to metabolites (diphenyl-methoxy-ethylamine, diphenyl-methoxy-acetic, diphenyl-methoxy-N-methylamine) (Gravol Canadian labeling 2016).
Half-life elimination: Oral: 5 to 8 hours (Gravol Canadian labeling 2016).
Excretion: Renal (Gravol Canadian labeling 2016).