Hypotension, hypothermia, central respiratory depression and bradycardia may develop in cases of severe overdosage. Diarrhea may also occur. Signs are dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, gastrointestinal disturbances, mental confusion, delirium, convulsions, shock, coma. Hydrochlorothiazide may precipitate hepatic coma in cirrhotics, potentiate other antihypertensive agents, and decrease responsiveness to norepinephrine. There is no specific antidote.
Treatment is symptomatic and supportive.
Evacuate stomach contents, taking adequate precautions against aspiration and for the protection of the airway, instill activated charcoal slurry. Correct dehydration, electrolyte imbalance, hepatic coma, by established procedures. Administer oxygen or artificial respiration for respiratory impairment. If bradycardia becomes marked, especially with cardiac arrhythmias, consider the use of vagal blocking agents along with other appropriate measures. Since reserpine is long acting, watch the patient carefully for at least 72 hours, administering treatment as required.