Digesic - Available Forms

Available Forms

Propoxyphene was initially introduced as propoxyphene hydrochloride. Shortly before the patent on propoxyphene expired, propoxyphene napsylate form was introduced to the market. Napsylate salt (the salt of naphthalenesulfonic acid) is claimed to be less prone to abuse, because it is almost insoluble in water, so cannot be used for injection. Napsylate also gives lower peak blood level. Because of different molecular mass, a dose of 100 mg of propoxyphene napsylate is required to supply an amount of propoxyphene equivalent to that present in 65 mg of propoxyphene hydrochloride.

Before the FDA-directed recall, dextropropoxyphene HCl was available in the United States as a prescription formulation with paracetamol (acetaminophen) in ratio from 30 mg / 600 mg to 100 mg / 650 mg (or 100 mg / 325 mg in the case of Balacet), respectively. These are usually named Darvocet. Darvon is a pure propoxyphene preparation that does not contain paracetamol.

In Australia, dextropropoxyphene is available on prescription, both as a combined product (32.5 mg dextropropoxyphene per 325 mg paracetamol branded as Di-gesic, Capadex, or Paradex; it is also available in pure form (100 mg capsules) known as Doloxene.