Relaxation of capacitance vessels and reduction in total peripheral resistance . Slow heart rate or AV node conduction problems. History of mental depression. Such patients should not receive clonidine, and the drug should be stopped if depression appears. Withdrawal of clonidine after protracted use can result in life-threatening hypertensive crisis.
Patients exhibit nervousness, tachycardia, headache, and sweating.
Concurrent treatment can block antihypertensive effect of clonidine.