Cardiovascular responses to mianserin hydrochloride: a comparison with tricyclic antidepressant drugs.

1. The cardiovascular responses of mianserin hydrochloride and tricyclic antidepressant drugs were investigated using non-invasive methods of cardiac investigation. A study of the interaction of mianserin and antihypertensive drug therapy is reported. 2. In six normal volunteers, mianserin hydrochloride 20 mg was shown to prolong the corrected Q-T interval at 150 min (P less than 0.001). It did not affect heart rate, systolic time intervals or the peak normalized derivative of the apexcardiogram. Amitriptyline 50 mg increased the corrected pre-ejection period interval (PEPI) and the PEP/left ventricular ejection time (LVET) ratio of the systolic time intervals at 150 min (P less than 0.001). Q-T interval was shortened at 90 minutes. 3. In a double-blind patient study, clomipramine increased heart rate, P-R interval, QRS and corrected Q-T interval in one patient at 2 weeks. Mianserin prolonged corrected Q-T interval at 1 week but this returned to the pretreatment time by 2 weeks in two patients. 4. In an open study, mianserin 20 mg three times daily did not antagonize the hypotensive action of propranolol or propranolol and hydrallazine in three patients. 5. In a double-blind study in three patients with desmethylimipramine 25 mg three times daily, mianserin 20 mg three times daily did not antagonize the hypotensive action of either guanethidine or bethanidine.