How does clonidine cause constipation?

akulahawkRN, ADN, RN, EMT-P · Mar 23, 2013

While I'm not entirely certain about the mechanism, think about what antihypertensives do to smooth muscle. After all, there is quite a bit of smooth muscle in the arteries, veins, and the G.I. tract…

Esme12, ASN, BSN, RN · Mar 23, 2013

Think about the sympathetic nervous system and this drug and the reduction the "fight flight" response causing a drying up/slow down effect on the patient. Some anti-hypertensives are also diuretics.....causing a further dying up situation.

Clonidine treats high blood pressure by stimulating α₂ receptors in the brain, which decreases cardiac output and peripheral vascular resistance, lowering blood pressure. It has specificity towards the presynaptic α₂ receptors in the vasomotor center in the brainstem. This binding decreases presynaptic calcium levels, and inhibits the release of norepinephrine (NE). The net effect is a decrease in sympathetic tone.
It has also been proposed that the antihypertensive effect of clonidine is due to agonism on the I₁-receptor (imidazoline receptor), which mediates the sympatho-inhibitory actions of imidazolines to lower blood pressure.

Medications for treating hypertension - Harvard Health Publications