Phenyramidol-associated liver toxicity

OBJECTIVE: To describe a case of hepatotoxicity associated with phenyramidol use that resolved after discontinuation of the drug. BACKGROUND: Phenyramidol is a moderately potent and relatively nontoxic analgesic with concomitant muscle-relaxant activity. A MEDLINE search in June 2003 revealed no reports associating hepatotoxicity with this agent. CASE SUMMARY: A 70-year-old man was investigated because of elevated liver function test values on routine biochemical screening. He had no clinical symptoms. Other etiologies of hepatitis were appropriately ruled out, and elevated enzymes were ascribed to phenyramidol treatment. DISCUSSION: This is the first case published in the English language literature describing probable hepatotoxicity, according to the Naranjo probability scale, resulting from use of phenyramidol. The mechanism of phenyramidol-induced liver damage is unknown. Several features, such as the absence of predictable dose-dependent toxicity of phenyramidol in previous studies and the absence of hypersensitivity manifestations in our patient, are suggestive of a metabolic type of idiosyncratic toxicity. CONCLUSIONS: Phenyramidol should be considered as a drug that possibly causes hepatotoxicity.