Version July 2025
| Medication | Available without a prescription (over-the-counter)? | Usual adult dose (oral, unless noted) | Onset of action | Common side effects |
| Bulk-forming laxatives* | ||||
| Psyllium | Yes | Powder: Up to 1 teaspoon (≅3.5 g fiber) 3 times per day | 12 to 72 hours | Impaction above strictures, fluid overload, gas and bloating |
| Methylcellulose | Yes | Caplet: Up to 4 caplets (500 mg fiber per caplet) 3 times per day Powder: Up to 1 tablespoon (≅2 g fiber) 3 times per day | 12 to 72 hours | |
| Polycarbophil | Yes | Tablet: 2 tablets (500 mg fiber per tablet) up to 4 times per day | 24 to 48 hours | |
| Wheat dextrin | Yes | Caplet: 3 caplets (1 g fiber per caplet) up to 3 times per day Chewable tablet: 3 tablets (1 g fiber per tablet) up to 3 times per day Gummy: 3 gummies (2 g fiber per gummy) up to 3 times per day Powder: 2 teaspoons (≅1.5 g fiber per teaspoon) up to 3 times per day | 24 to 48 hours | |
| Osmotic agents | ||||
| Polyethylene glycol 3350 (PEG 3350; also called macrogol) | Yes | 8.5 to 34 g once daily; dissolve dose in 240 mL (8 ounces) liquid | 1 to 4 days | Nausea, bloating, cramping |
| Lactulose | No | 10 to 20 g (15 to 30 mL or 1 to 2 packets) once daily or every other day; may increase up to 2 times per day | 24 to 48 hours | Abdominal bloating, flatulence |
| Sorbitol | Yes | 30 to 45 mL (70% solution) once daily | 24 to 48 hours | Abdominal bloating, flatulence |
| Glycerin (glycerol) | Yes | One suppository (2 g) per rectum once daily; retain for approximately 15 minutes | 15 to 60 minutes | Rectal irritation |
| Magnesium sulfate | Yes | 2 to 4 level teaspoons (approximately 10 to 20 g) of granules once daily; may repeat in 4 hours. Dissolve each dose in 240 mL (8 ounces) of water. Do not exceed 2 doses per day. | 0.5 to 3 hours | Watery stools and urgency; caution in kidney insufficiency (magnesium toxicity) |
| Magnesium citrate | Yes | 200 mL (11.6 g) once daily | 0.5 to 3 hours | |
| Magnesium hydroxide | Yes | 400 mg/5 mL solution: 15 to 60 mL once daily | 0.5 to 6 hours | |
| Stimulant laxatives | ||||
| Bisacodyl | Yes | Enteric-coated tablet: 5 to 15 once daily as needed | 6 to 10 hours | Gastric irritation |
| Yes | Suppository: 10 mg per rectum once daily as needed; retain for approximately 15 minutes | 15 to 60 minutes | Rectal irritation | |
| Senna | Yes | 2 to 4 tablets (8.6 mg sennosides per tablet) or 1 to 2 tablets (15 mg sennosides per tablet) as a single daily dose or divided twice daily as needed | 6 to 12 hours | Melanosis coli |
| Sodium picosulfate (where available; not available in the United States) | Yes | Oral solution: 5 to 10 mg once daily as needed; dose volume differs based on formulation, refer to local product information Tablet: 5 to 10 mg once daily as needed | 6 to 12 hours | Diarrhea, abdominal pain |
| Secretagogues | ||||
| Linaclotide | No | 145 micrograms once daily on an empty stomach ≥30 minutes before a meal | 12 to 24 hours | Diarrhea, bloating |
| Plecanatide | No | 3 mg once daily | 12 to 24 hours | Diarrhea |
| Lubiprostone | No | 24 micrograms twice daily | 24 to 48 hours | Nausea, diarrhea |
| Other agents | ||||
| Tenapanor (sodium/hydrogen exchanger 3 inhibitor) | No | 50 mg twice daily | 12 to 24 hours | Diarrhea |
| Prucalopride (prokinetic agent) | No | 2 mg once daily | 6 to 12 hours | Nausea, headache, diarrhea |
| Vibrating capsule (nonpharmacologic) | No | 1 capsule once daily at bedtime, 5 days a week (ie, 3 days on, 1 day off, 2 days on, 1 day off) | 6 to 18 hours | Vibrating sensation |
| Stool softeners (surfactant agents) | ||||
| Docusate sodium | Yes | 100 mg once or twice daily | 24 to 72 hours | Well tolerated, but less effective than other agents. Use lower dose if administered with another laxative. Contact dermatitis reported. |
| Docusate calcium | Yes | 240 mg once daily | 24 to 72 hours | |
Courtesy of Arnold Wald, MD.
Additional data from:
