Droperidol

Droperidol may potentiate the action of sedatives (barbiturates, benzodiazepines, morphine derivatives). The same applies to antihypertensive agents, so that orthostatic hypotension may ensue.

Since droperidol blocks dopamine receptors, it may inhibit the action of dopamine agonists, such as bromocriptine, lisuride, and of L-dopa.

Consumption of alcoholic beverages and medicines should be avoided.

Patients who have, or are suspected of having, a history of alcohol abuse or recent high intakes, should be thoroughly assessed before droperidol is administered.

To reduce the risk of QT prolongation, caution is necessary when patients are taking medicinal products likely to induce electrolyte imbalance (hypokalaemia and/or hypomagnesaemia) e.g. potassium-wasting diuretics, laxatives and glucocorticoids.

Droperidol may potentiate respiratory depression caused by opioids.

Substances inhibiting the activity of cytochrome P450 iso-enzymes (CYP) CYP1A2, CYP3A4 or both could decrease the rate at which droperidol is metabolised and prolong its pharmacological action. Hence, caution is advised if droperidol is given concomitantly with CYP1A2 inhibitors, CYP3A4 inhibitors or both.

In patients with renal and/or hepatic impairment, when preventing and treating post-operative nausea and vomiting (PONV), the dose of droperidol should be restricted to 0.625 mg (0.25 ml).

Concomitant use of medicinal products that induce extrapyramidal symptoms, e.g. metoclopramide and other neuroleptics, may lead to an increased incidence of these symptoms and should therefore be avoided.

Patients with, or suspected of having, the following risk factors for cardiac arrhythmia should be carefully evaluated prior to administration of droperidol:

• a history of significant cardiac disease including serious ventricular arrhythmia, second or third degree atrio-ventricular block, sinus node dysfunction, congestive heart failure, ischemic heart disease and left ventricular hypertrophy;
• family history of sudden death;
• renal failure (particularly when on chronic dialysis);
• significant chronic obstructive pulmonary disease and respiratory failure;
• risk factors for electrolyte disturbances, as seen in patients taking laxatives, glucocorticoids, potassium-wasting diuretics, in association with the administration of insulin in acute settings, or in patients with prolonged vomiting and/or diarrhoea.

Patients at risk for cardiac arrhythmia should have serum electrolytes and creatinine levels assessed and the presence of QT prolongation excluded prior to administration of droperidol.

Continuous pulse oximetry should be performed in patients with identified or suspected risk of ventricular arrhythmia and should continue for 30 minutes following single i.v. administration.

Use with caution in patients with epilepsy (or a history of epilepsy) and conditions predisposing to epilepsy or convulsions.

A limited amount of clinical data have shown no increase of malformative risk.

Droperidol has not been shown to be teratogenic in rats. Animal studies are insufficient with respect to the effects on pregnancy and embryonal/foetal, parturition and postnatal development.

In newborn babies from mothers under long-term treatment and high doses of neuroleptics, temporary neurological disturbances of extrapyramidal nature have been described.

In practice, as a precautionary measure, it is preferable not to administer droperidol during pregnancy. In late pregnancy, if its administration is necessary, monitoring of the newborn’s neurological functions is recommended.

Neuroleptics of the butyrophenone type are known to be excreted in breast milk; treatment with droperidol should be limited to a single administration. Repeat administration is not recommended.

Fertility

There were no effects on fertility in studies conducted in male and female rats. The clinical effect of droperidol on fertility has not been established.

Droperidol has major influence on the ability to drive and use machines.

Patients should not drive or operate a machine for 24 hours after droperidol administration.