<p>Allopurinol should be withdrawn immediately when a skin rash&nbsp;or other evidence of sensitivity occurs. Reduced doses should be used in&nbsp;patients with hepatic or renal impairment. Patients under treatment for&nbsp;hypertension or cardiac insufficiency may have some concomitant&nbsp;impairment of renal function and allopurinol should be used with care in this&nbsp;group.</p>