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DRUG INTERACTIONS
Drug Interactions:
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. Following the administration
of droperidol, the dose of other CNS depressant drugs should be reduced.
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OVERDOSAGE
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 BOX 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 is 20 ― 43 mg/kg in mice; 30 mg/kg in
rats; and 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.
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CONTRAINDICATIONS
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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REFERENCES
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Saarnivaara L, Klemola UM, Lindgren L, et al. QT interval of the ECG, heart rate and arterial pressure using propofol, methohexital or midazolam for induction of anesthesia. Acta Anaesthesiol Scand 1990: 34: 276-81.
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Schmeling WT, Warltier DC, McDonald DJ, et al. Prolongation of the QT interval by enflurane, isoflurane, and halothane in humans. Anesth Analg 1991:72:137-44.
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Späth G. Torsade des pointe oder die andere Ursache des plötz-lichen Herztodes. Wien: Ueberreuter, 1998.
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Riley DC, Schmeling WT, Al-Wathiqui MH, et al. Prolongation of the QT-interval by volatile anesthetics in chronically instrumented dogs. Anesth Analg 1988: 67: 741-9.
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McConachie I, Keaveny JP, Healy TF, et al. Effects of anaesthesia on the QT-interval. Br J Anaesth 1989: 63: 558-60.
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Lawrence KR, Nasraway SA. Conduction disturbances associated with administration of butyrophenone antipsychotics in the critically ill: a review of the literature. Pharmacotherapy 1997: 17(3): 531-7.
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Lischke V, Behne M, Doelken P, et al. Droperidol causes a dose-dependent prolongation of the QT interval. Anesth Analg 1994: 79: 983-6.
Revised: October, 2004
©
Hospira 2004 EN-0531 Printed in USA
HOSPIRA, INC., LAKE FOREST, IL 60045 USA
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