Haloperidol intravenous – a preliminary risk assessment
Key points of the discussion in the sight of a clinician: A warning of the US-American FDA in 2007 concerning the intravenous application of haloperidol has evoked a broad discussion and some constraint of the therapeutical use. Recommendations were given to perform monitoring and to avoid intravenous application. But the FDA warning did not differentiate between intravenous bolus-injection and drip-feeding. Also, haloperidol shows an advantageous cardiac risk profile within the group of antipsychotics. Perhaps the application as intravenous drip-feeding could reduce the cardiac risk? Risk assessment from the point of view of a clinical pharmacologist: Drugs applied intravenously as bolus lead to an initial plasma peak. When added to intravenous fluids, haloperidol can precipitate. In a small trial performed with glucose 5% solution, haloperidol did not precipitate. So it could be used for an intravenous drip instead of bolus to avoid initial plasma peaks which might be responsible for cardiac complications. In pharmacokinetic studies, the dose and the plasma concentration of haloperidol correlated only very weakly. Just as well, the dose taken and the QTc interval prolongation associated with cardiac complications correlated only very weakly. Therefore, a pharmacological modelling is hardly feasible, and no specific infusion speed can be recommended. Clinical risk factors are very important and should be paid attention to by all appliances of haloperidol.