Idiopathic orthostatic hypotension, midodrine, and anaesthesia.

A patient with idiopathic orthostatic hypotension receiving chronic oral midodrine therapy required anaesthesia for coronary artery bypass grafting. A perioperative infusion of phenylephrine was substituted for midodrine, an alpha-2 agonist, enabling hypotension resulting from low systemic vascular resistance to be controlled easily. Anticipated adrenergic receptor denervation hypersensitivity was noted. The only significant perioperative problem was one episode of syncope from orthostatic hypotension during the reambulation period.