Influence of Milk on Haloperidol Pharmacokinetics

Psychiatric patients try to alleviate the effects of the butyrophenone neuroleptic haloperidol (HAL) by concomitant intake of milk or other dairy products. To determine whether this corresponded to milk-induced changes in HAL pharmacokinetics, male volunteers ingested a 10 mg HAL tablet (Haldol R ) with 250 ml tap water ( n = 10) or 250 ml milk ( n = 9). Plasma HAL levels were determined up to 24 hr. Coadministration of 250 ml milk delayed the initial increase in haloperidol plasma levels (time lag [ T lag ] increased 1.6-fold). However, of all 9 time points compared, only the HAL level difference at 1.5 hr after ingestion reached statistical significance ( p = .04). Differences in T lag , HAL levels for times < 1.5 hr, and the decrease in terminal half-life (t ½ β) by milk all showed statistical trends ( p from .07 to .18). Because of the severity and high incidence of acute HAL side effects (akathisia, dysphoria, and anxiety), the original crossover design was abandoned and the study discontinued.