Blood pressure over-shoot due to acute clonidine (Catapres) withdrawal: studies on arterial and urinary catecholamines and suggestions for management of the crisis

1. Clonidine was withdrawn acutely in five hypertensive patients with a documented blood pressure over-shoot after previous temporary cessation of treatment.

2. In all patients a severe rise of systolic and diastolic blood pressure was seen (average 67/58 mmHg). This was accompanied by a number of ‘withdrawal symptoms’, e.g. restlessness, tremor, headaches and nausea.

3. Catecholamines in urine rose from 32 μg/l to 112 μg/l (001 < P < 0.02) and in arterial blood from 0.52 μg/l to 1.0 μg/l (not significant).

4. The crisis could be reversed acutely by α- and β-adrenergic blockade.

5. Catecholamine depletion with reserpine before the withdrawal of clonidine seemed to reduce the blood pressure rise and the withdrawal symptoms.

Effects of clonidine withdrawal: possible mechanisms and suggestions for management

A severe rebound rise in blood pressure with agitation and insomnia had been noted in five patients when they had previously ceased clonidine (Catapres) This has been shown to be reproducible in these patients and to be associated with a significant increase in urinary catecholamine excretion. The blood pressure can be controlled and the symptoms alleviated promptly by alpha and beta adrenergic receptor blockade using intravenous phentolamine and propranolol.