In Brief: Propoxyphene Toxicity
The FDA has required manufacturers of propoxyphene-containing products (Darvon, and others) to strengthen boxed warnings to include the potential for overdose.1 This action followed disclosure of fatal overdoses linked to propoxyphene-containing products taken alone or concurrently with other CNS depressants, including alcohol. Many of the overdoses occurred in patients with a history of emotional instability or suicide attempts. Accumulation of metabolites of propoxyphene can lead to central nervous system, cardiac and respiratory depression; convulsions and cardiotoxicity have occurred.
A Schedule IV controlled substance, propoxyphene is a weak full agonist opioid indicated for relief of mild to moderate pain.2 It is often prescribed in combination with acetaminophen (Darvocet, and others). One reasonable alternative would be codeine with acetaminophen; 32 mg of codeine has an analgesic effect similar to that of 65 mg of propoxyphene. Another would be 400 mg of ibuprofen, which may be more effective than either propoxyphene or codeine combined with acetaminophen.
1. FDA News Release. FDA takes actions on Darvon, other pain medications containing propoxyphene. Available at www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm170769.html. Accessed August 23, 2010.