[A case of amphetamine-induced down-regulation of beta-adrenoceptor].

A 29-year-old man with severe pyloric stenosis confessed that he had been a chronic amphetamine abuser just after awakening from anesthesia for partial gastrectomy. Anesthesia was maintained with thoracic epidural bupivacaine combined with continuous i.v. infusion of propofol. Decreased arterial blood pressure was observed 10 min after starting epidural anesthesia, and remained stable at 80-90 mmHg of systolic blood pressure in spite of massive fluid resuscitation in addition to repeated i.v. administration of ephedrine/methoxamine and continuous i.v. infusion of dopamine at a rate of 8 micrograms.kg-1.min-1. Finally, arterial blood pressure rose gradually after i.v. administration of methylpredonisolone 500 mg. We speculate that the down-regulation of beta-adrenoceptor induced by the sympathomimetic action of amphetamine, might be a major cause of refractory hypotension.