Butorphanol

It is a mixed opioid agonist/antagonist analgesic. In the central nervous system, it has agonist activity at the kappa and sigma receptors. Antagonist effects may be due to failure to substitute for m-receptor agonists sufficiently to prevent or attenuate withdrawal symptoms in physically dependent patients. Apart from analgesia, other CNS effects include depression of spontaneous respiratory activity and cough, stimulation of the emetic centre, miosis and sedation.

Indications

Treatment of moderate to severe pain, adjunct to anaesthesia.

Dosage

For pain relief : Initially 1mg IV, or 2mg IM with repeated doses every 3-4 hours, as necessary. The initial dose in the elderly and in patients with renal or hepatic impairment should generally be half the recommended adult dose. For pre-operative use: IV, usually 2mg sixty to ninety minutes prior to surgery, although the dose must be individualised. For balanced anaesthesia : IV, initially 1 to 4 mg, followed by supplemental doses of 500mcg to 1mg as needed.

Contra-Indications

Diarrhoea associated with pseudomembranous colitis, acute respiratory depression.

Special Precautions

Patients with renal/hepatic impairment, during labour, hypertension, acute myocardial infarction.

Side Effects

Physical dependence, respiratory depression, confusion, convulsions, hallucinations, hepatotoxicity, hypertension, paradoxical CNS excitation.

Drug Interactions

Alcohol, barbiturates, tranquilizers, antihistamines, cimetidine, erythromycin, theophylline etc.