FENTANYL

It is an exceptionally potent synthetic opioid. It has rapid onset of action with the added advantage of acting for a short duration and causes fewer side effects than morphine and has minimal effects on the cardiovascular system.

Indications

Provide analgesia during short surgical procedures. Used as premedication, during anaesthetic period, induction and maintenance, and in the immediate postoperative period. In combination with a neuroleptic for inducing neuroleptanalgesia. As a general anaesthetic along with oxygen and muscle relaxants and as an adjunct to regional anaesthesia.

Dosage

Premedication: 50-100 mcg im 30-60 minutes before surgery. Adjunct to general anaesthesia: Low doses in minor but painful procedures: 2 mcg/kg IV repeated if necessary. Moderate doses (major surgery): 2-20 mcg/kg initially. High doses (open heart or similar complex procedures): 25-50 mcg/kg IV. Adjunct to regional anaesthesia: 50-100 mcg IM or slow IV over 1-2 min. Post-op in recovery room: 50-100 mcg IM. Children (2-12 yrs.): 2-3 mcg/kg for induction and maintenance.

Contra-Indications

Respiratory depression, obstructive airway disease, raised intracranial pressure, hypovolemia/hypotension, myasthenia gravis, concurrent use of MAOIs or within 2 weeks after stopping them, hypersensitivity.

Special Precautions

Head injury, reduced dose in debilitated patients, hepatic and renal impairment. Fentanyl citrate is incompatible with thiopentone sodium methohexitone sodium. Paediatrics: Reduce the dose. Pregnancy: Should not be administered unless the possible benefits are greater than potential risk to the foetus. Lactation: Stop breast feeding. Elderly: Dose reduction may be required.

Side Effects

Nausea, vomiting, bradycardia, hypotension, pruritus, respiratory depression. Reduction in pulmonary compliance, apnoea, laryngospasm and bronchoconstriction. Seizures. Urinary retention may occur after epidural administration of fentanyl.

Drug Interactions

CNS depressants such as benzodiazepines, barbiturates, tranquillizers and general anaesthetics may have additive or potentiating effects. Atracurium and vecuronium may result in severe bradycardia.