Potentially Arrhythmogenic Agents: Any drug known to have the potential to prolong the QT interval should not be used together with droperidol. Possible pharmacodynamic interactions can occur between droperidol and potentially arrhythmogenic agents such as class I or III antiarrhythmics, antihistamines that prolong the QT interval, antimalarials, calcium channel blockers, neuroleptics that prolong the QT interval, and antidepressants.
Caution should be used when patients are taking concomitant drugs known to induce hypokalemia or hypomagnesemia as they may precipitate QT prolongation and interact with droperidol. These would include diuretics, laxatives and supraphysiological use of steroid hormones with mineralocorticoid potential.
CNS Depressant Drugs: Other CNS depressant drugs (e.g. barbiturates, tranquilizers, opioids and general anesthetics) have additive or potentiating effects with droperidol. When patients have received such drugs, the dose of droperidol required will be less than usual. Following the administration of droperidol, the dose of other CNS depressant drugs should be reduced.
Manifestations: The manifestations of droperidol overdosage are an extension of its pharmacologic actions and may include QT prolongation and serious arrhythmias (e.g., torsade de pointes) (see BOXED WARNING, WARNINGS, and PRECAUTIONS).
Treatment: In the presence of hypoventilation or apnea, oxygen should be administered and respiration should be assisted or controlled as indicated. A patent airway must be maintained; an oropharyngeal airway or endotracheal tube might be indicated. The patient should be carefully observed for 24 hours; body warmth and adequate fluid intake should be maintained. If hypotension occurs and is severe or persists, the possibility of hypovolemia should be considered and managed with appropriate parenteral fluid therapy. (see PRECAUTIONS).
If significant extrapyramidal reactions occur in the context of an overdose, an anticholinergic should be administered.
The intravenous Median Lethal Dose of droperidol is 20-43 mg/kg in mice; 30 mg/kg in rats; 25 mg/kg in dogs and 11-13 mg/kg in rabbits. The intramuscular Median Lethal Dose of droperidol is 195 mg/kg in mice; 104-110 mg/kg in rats; 97 mg/kg in rabbits and 200 mg/kg in guinea pigs.
Droperidol is contraindicated in patients with known or suspected QT prolongation (i.e., QTc interval greater than 440 msec for males or 450 msec for females). This would include patients with congenital long QT syndrome.
Droperidol is contraindicated in patients with known hypersensitivity to the drug.
Droperidol is not recommended for any use other than for the treatment of perioperative nausea and vomiting in patients for whom other treatments are ineffective or inappropriate (see WARNINGS).
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SHIRLEY, NY 11967
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