Major
clonidine × Propranolol
Central α2-adrenergic agonist×Non-selective beta blocker
Mechanism
Propranolol is a non-selective beta-blocker (β1 and β2). On abrupt clonidine withdrawal, additional β2-blockade amplifies the residual α1 effect, making the hypertensive crisis particularly severe.
Symptoms
Abrupt clonidine withdrawal causes hypertensive crisis: sharp blood pressure rise, headache, tachycardia, anxiety, sweating. Symptoms appear 18–24 hours after a missed clonidine dose.
Management
For planned clonidine withdrawal, stop propranolol 3–7 days beforehand, then taper clonidine over 1–2 weeks. Alternative antihypertensives: an ACE-I plus amlodipine (without clonidine) or a selective beta-blocker (bisoprolol).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.