Morphine Rifampicin

OPIOIDS RIFAMPICIN 1 effect of alfentanil, codeine, methadone and morphine Rifampicin t hepatic metabolism of these opioids (alfentanil by CYP3A4, codeine by CYP2D6, morphine unknown). Rifampicin is also known to induce intestinal P-gp, which may 1 bioavailability of oral morphine Be aware that alfentanil, codeine, methadone and morphine doses may need to be t... 

Other drugs are metabolised by Phase II synthetic reactions, catalysed typically by non-microsomal enzymes. Processes include acetylation, sulphation, glycine conjugation and methylation. Phase II reactions may be affected less frequently by ageing. Thus according to some studies, the elimination of isoniazid, rifampicin (rifampin), paracetamol (acetaminophen), valproic acid, salicylate, indomethacin, lorazepam, oxazepam, and temazepam is not altered with age. However, other studies have demonstrated a reduction in metabolism of lorazepam, paracetamol (acetaminophen), ketoprofen, naproxen, morphine, free valproic acid, and salicylate, indicating that the effect of age on conjugation reactions is variable. 

The metabolism of morphine is enhanced by rifampicin, resulting in loss of analgesic effects of morphine (56). 

Rifampicin markedly increases the metabolism of codeine and morphine, and reduces their effects. Rifampicin dramatically reduced the effects of oxycodone in one patient. 

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