Examples of drugs known to be safe or unsafe in the acute porphyrias

NSAIDs: nonsteroidal antiinflammatory drugs.
* Serotonin 5HT3 antagonists are probably safe. Classification of metoclopramide is controversial but is generally a less effective antiemetic.
¶ Not all agents within the same class will necessarily have the same risk. For example, though opioids are generally considered safe, pentazocine may be unsafe. Benzodiazepines that are rapidly metabolized or administered in low doses are considered safe, but the safety of high doses or prolonged use of long-acting agents is less certain. There are conflicting reports on the safety of cephalosporins.
Δ In United States labeling for these drugs, porphyria is listed as a contraindication, warning, precaution, or adverse effect. Erythropoietin is regarded as safe by other sources. Estrogens are unsafe for porphyria cutanea tarda but can be used with caution in the acute porphyrias, especially in low doses or by the transdermal route.