Dihydrocodeine as an opioid analgesic for the treatment of moderate to severe chronic pain.

Dihydrocodeine (DHC) is a semi-synthetic analogue of codeine which was formed by the hydrogenation of the double tie in the main chain of the codeine molecule. DHC is used as an analgesic, antitussive and antidiarrhoeal agent; it is also used for the treatment of opioid addiction. Limited data is available on the relative potency of DHC to other opioids. The analgesic effect of DHC is probably twice as potent as codeine for the parenteral and slightly stronger for an oral route. DHC possesses approximately 1/6(th) of the morphine analgesic effect when drugs are administered orally. In this article pharmacokinetics, pharmacodynamics, dosing guidelines, adverse effects and clinical studies of DHC in pain management are shown with focus on cancer pain. The impact of CYP2D6 activity on DHC analgesia was discussed and a proposal of calculation equianalgesic doses of DHC to other opioids was put forward.