Editing Haloperidol (section)

=== Interactions ===
* [[Amiodarone]]: Q-Tc interval prolongation (potentially dangerous change in heart rhythm).<ref>{{cite journal | vauthors = Bush SE, Hatton RC, Winterstein AG, Thomson MR, Woo GW | title = Effects of concomitant amiodarone and haloperidol on Q-Tc interval prolongation | journal = American Journal of Health-System Pharmacy | volume = 65 | issue = 23 | pages = 2232–2236 | date = December 2008 | pmid = 19020191 | doi = 10.2146/ajhp080039 }}</ref>
* [[Amphetamine]] and [[methylphenidate]]: counteracts increased action of norepinephrine and dopamine in patients with [[narcolepsy]] or [[Attention deficit disorder|ADD]]/[[ADHD]]
* [[Epinephrine]]:  action antagonized, paradoxical decrease in blood pressure may result
* [[Guanethidine]]:  antihypertensive action antagonized
* [[Levodopa]]:  decreased action of levodopa
* [[Lithium (medication)|Lithium]]:  rare cases of the following symptoms have been noted: [[encephalopathy]], early and late extrapyramidal side effects, other neurologic symptoms, and coma.<ref>{{cite journal | vauthors = Sandyk R, Hurwitz MD | title = Toxic irreversible encephalopathy induced by lithium carbonate and haloperidol. A report of 2 cases | journal = South African Medical Journal = Suid-Afrikaanse Tydskrif vir Geneeskunde | volume = 64 | issue = 22 | pages = 875–876 | date = November 1983 | pmid = 6415823 }}</ref>
* [[Methyldopa]]:  increased risk of extrapyramidal side effects and other unwanted central effects
* Other central depressants (alcohol, tranquilizers, narcotics):  actions and side effects of these drugs (sedation, respiratory depression) are increased. In particular, the doses of concomitantly used opioids for chronic pain can be reduced by 50%.
* Other drugs metabolized by the CYP3A4 enzyme system: inducers such as [[carbamazepine]], [[phenobarbital]], and [[rifampicin]] decrease plasma levels and inhibitors such as [[quinidine]], [[buspirone]], and [[fluoxetine]] increase plasma levels<ref name=FDA />
* [[Tricyclic antidepressants]]:  metabolism and elimination of tricyclics significantly decreased, increased toxicity noted (anticholinergic and cardiovascular side effects, lowering of seizure threshold)