<p>Sympathomimetic agents may cause a hypertensive crisis if used during treatment with MAOIs. Concomitant use with MAOIs is therefore contraindicated.<br />
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Sedating anti-histamines can enhance the sedating effects of CNS depressant including alcohol, hypnotics, opioid analgesics, anxiolytic sedatives and anti-psycotics. They also have an additive anti-muscarinic action with other anti muscarinic drugs, such as atropine and antidepressant</p>