Clonidine constipation with

It is estimated that about 7% of patients receiving clonidine discontinue the drug because of side effects. Although the symptoms are generally mild and tend to subside if therapy is continued for several weeks, as many as 50% of the patients complain of drowsiness and dryness of mouth. Other untoward effects include constipation, nausea or gastric upset, and impotence. These effects are characteristic of interference with the functioning of the sympathetic nervous system. 

Constipation is frequent with clonidine, and one case of pseudo-obstruction of the bowel has been reported (19). 

Side effects of clonidine therapy include dry mouth, drowsiness, sedation, and constipation. Abrupt discontinuation of therapy may result in a withdrawal syndrome manifested as restless and headache in addition to significant rebound hypertension. Withdrawal can be avoided by tapering therapy over 2-4 days. The incidence of a local dermatitis or an extended dermal reaction with use of the transdermal patch is 15-20%. 

Clonidine (Catapres) Acts in brain as postsynaptic a2-adrenergic agonist causing a reduction in sympathetic nervous system activity (decreased heart rate, cardiac ouput and blood pressure). Exact mechanism unknown. Mild to moderate hypertension. Rash, drowsiness, dry mouth, constipation, headache, impaired ejaculation. Rebound hypertension if withdrawn abruptly. To limit toxicity, start with low dose and increase slowly. 

An advantage of clonidine is the absence of orthostatic hypotension, but like a-methyldopa and reserpine it may cause drowsiness, and marked sedation occurs in up to 50% of patients treated in some series. Sedation can be so severe as to proceed to semi-consciousness. Nightmares and delusions are another expression of the drug s influence upon the central nervous system. Apart from sedation, the complaint of dry mouth and nose is the most common side effect recorded with clonidine administration. Dizziness, headache and fatigue are frequently mentioned, as well as anorexia, nausea, constipation and even pseudo-obstruction (94 ), anxiety, depression, drug fever and rashes. Side effects occur in 50—70% of the patients treated and are in some 20% the reason for discontinuation of therapy (3 , 13, 83 ). 

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