<p><strong>In patients with benign prostatic hyperplasia</strong>: Prazosin is not recommended for patients with a history of micturition syncope. It should not normally be administered to patients already receiving another alpha-1-antagonist.<br />
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<strong>In patients with congestive heart failure</strong>: Prazosin is not recommended in the treatment of congestive cardiac failure due to&nbsp;mechanical&nbsp;obstruction such as aortic valve stenosis, mitral valve stenosis, pulmonary embolism and restrictive pericardial disease.<br />
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<strong>In patients with hypertension</strong>: Postural hypotension evidenced by dizziness and weakness, or rarely loss of consciousness, has been reported, particularly with the commencement of therapy.</p>