A patient on long-term clonidine for hypertension abruptly discontinues the drug. Two days later, she presents with severe headache, palpitations, and BP 210/130 mmHg. This rebound hypertension is due to:
- A Upregulation of postsynaptic adrenergic receptors and catecholamine surge ✓
- B Acute salt and water retention from renin release
- C Rebound bradycardia triggering baroreceptor-mediated pressor response
- D Supersensitivity of muscarinic receptors in the heart
Correct answer: A. Upregulation of postsynaptic adrenergic receptors and catecholamine surge
Explanation
Chronic clonidine use leads to downregulation of presynaptic α2 autoreceptors and upregulation of postsynaptic adrenergic receptors. On abrupt withdrawal, the suppressed sympathetic outflow is released, causing a catecholamine surge that acts on sensitized receptors, producing rebound hypertension. This is analogous to β-blocker withdrawal and requires gradual tapering.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.