Symptoms of prochlorperazine overdose:
Overdose of prochlorperazine may cause different toxic manifestations include
► Central nervous system depression to the point of drowsiness or loss of consciousness.
► Cardiac arrhythmias including ventricular tachycardia, supraventricular tachycardia.
► ECG changes such as prolongation of QT interval, atrio-ventricular block.
► Autonomic reactions including hypotension, shock.
► Severe extra pyramidal muscular dystonic reactions – Symptoms of this condition are bizarre spasms of the tongue and facial muscle that producing grimacing, torticollis and locked jaw.
Treatment of prochlorperazine overdose:
► If the patient is seen within 6 hours after ingestion of drug with overdose, gastric lavage may be attempted. Gastric lavage means washing out of stomach by sterile water or normal saline using a tube. The purpose of this procedure is to remove the prochlorperazine from stomach and to cleanse it.
► Do not attempt to induce vomiting because severe extra pyramidal muscular dystonic reactions in tongue and facial muscle may develop that can cause aspiration of vomitus.
► Activated charcoal may be given. Charcoal is a very fine powder prepared from soft charred wood. It should be administered as soon as possible after ingestion of overdose of prochlorperazine. It is given orally as a suspension in water. Activated charcoal absorbs the ingested drugs.
► Generalised vasodilatation occurs in prochlorperazine overdose that may cause hypotension or shock. Raising the patient’s legs may correct this condition. In severe cases, intravenous (IV) fluid may be needed. In hypothermic patients, warmed intravenous fluid should be given. Positive inotropic drugs such as dopamine may be given to correct the shock. Peripheral vasoconstrictor drugs such as adrenaline (epinephrine) is not recommended because prochlorperazine may reverse the usual elevating action of these drugs and cause a further lowering of blood pressure.
► Cardiac arrhythmias usually respond to restoration of normal body temperature and correction of shock. If persistent or life threatening ventricular or supraventricular tachycardia present, appropriate anti-arrhythmic drug should be considered.
► Pronounced central nervous system depression requires airway maintenance or, in extreme circumstances, assisted ventilation.
► Severe muscular dystonic reactions usually respond to procyclidine or orphenadrine given intramuscularly or intravenously.
► If convulsion occurs, intravenous diazepam should be given.
► Prochlorperazine has no antidote (antidote is a substance that produces effects opposite to the effects of poison).
► Prochlorperazine is not dialyzable.