Haloperidol interaction

CJ-Receptors are localized ia the brain stem and limbic stmcture, regions associated with endocrine function (76). In the periphery, CJ-receptors are found in the Hver, heart, ileum, vas deferens, and on lymphocytes and thymocytes. Although there is insufficient evidence to clearly define the functional role of CNS CJ-sites, based on the effects of PCP and the interaction of haloperidol with CJ-sites, CJ-receptor ligands may be antipsychotics or used for the treatment of substance abuse. Several CJ-receptor ligands have shown neuroprotective effects in vivo. Ifenprodil (315) and CNS 1102 (316) are being developed for treatment of stroke (Table 18). 

The administration of low doses of PCP to rodents induces hyperactivity and stereotypy (Chen et al. 1959 ). The observation that neuroleptics such as chlorpromazine, haloperidol, and pimozide, and adrenolytics such as alpha-methyl paratyrosine antagonize these behavioral effects of PCP suggests that they are mediated by facilitation of central dopaminergic neurotransmission (Murray and Horita 1979). The actions of PCP on central dopaminergic neurotransmission may be similar to amphetamine. A dose of PCP (2.5 mg/kg) in rats, which has no effects when given alone, enhances the behavioral effects of 1 and 3 mg/kg of d-amphetamine (Balster and Chait 1978). PCP, like dopamine, has also been shown to suppress plasma prolactin (Bayorh et al. 1983). However, the firm establishment of an excl usive relationship between dopamine neuro-transmission and PCP effects is difficult because of the prominent interactions of this drug with other neurotransmitter systems. 

Saha N, Datta H, Sharma PL. (1991). Effects of morphine on memory interactions with naloxone, propranolol, and haloperidol. Pharmacology. 42(1) 10-14. 

There is another reason why medications exert multiple effects. For example, an antidepressant that very specifically promotes serotonin neurotransmission and has little or no interaction with other receptor types will still produce multiple effects. How can this be Remember that in different areas of the brain, a single neurotransmitter can assume very distinct roles. When an individual takes a medication that alters the activity of a particular neurotransmitter, it generally does so throughout the brain. Consequently, the dopamine receptor blocking effect of haloperidol (Haldol) reduces hallucinations and paranoia in one brain region but causes upper extremity stiffness through its action in another brain region. 

It may be fair to ask, Is this much ado about nothing Although test tube studies have shown that particular drugs interact, it is seldom that this causes problems for patients taking the medications. For example, the antidepressant fluvoxamine inhibits the enzyme that deactivates the antipsychotic haloperidol (Haldol). Does this mean that fluvoxamine and haloperidol cannot be taken together By no means. Although this would probably raise the blood level of haloperidol somewhat, the main effect if any would be that a smaller dose of haloperidol would be more effective. 

Drugs that interact with oxybutynin include atenolol, digoxin, haloperidol, phenothiazines, amantadine, and anticholinergic agents. 

Hypersensitivity to the drug or any other component of the product (cross-sensitivity between phenothiazines may occur) comatose or greatly depressed states caused by CNS depressants or from any other cause (phenothiazines, clozapine, loxapine, molindone, pimozide, haloperidol) coadministration with other drugs that prolong the QT interval and in patients with congenital long QT syndrome or history of cardiac arrhythmias (mesoridazine, thioridazine, pimozide, ziprasidone see Drug..Interactions). 

Hyoscyamine (Anaspaz, Cystospaz, Levsin, Others) [Antispasmodic/Anticholinergic] Uses Spasm w/ GI bladder disorders Action Anticholinergic Dose Adults. 0.125-0.25 mg (1-2 tabs) SL/PO tid-qid, ac hs 1 SR cap ql2h Caution [C, +] T Effects w/ amantadine, antihistamines, antimuscarinics, haloperidol, phenothiazines, TCA, MAOI Contra BOO, GI obst, NAG, MyG, paralytic ileus, ulcerative colitis, MI Disp Caps, tabs SE Dry skin, xerostomia, constipation, anticholinergic SE, heat prostration w/ hot weather Interactions T Effects W/ amantadine, antimuscarinics, haloperidol, phenothiazines,... 

Antiadrenergic] Uses HTN Action Centrally acting antihypCTtensive Dose Adults. 250-500 mg PO bid-tid (max 2-3 g/d) or 250 mg-1 g IV q6-8h Peds. 10 mg/kg/24 h PO in 2-3 doses (max 40 mg/kg/24 h q6-12h) or 5-10 mg/kg/dose IV q6-8h to total dose of 20 0 mg/kg/24 h X in renal insuff/elderly Caution [B (PO), C (IV), +] Contra Liver Dz MAOIs Disp Tabs, inj SE Discolors urine initial transient sedation/drowsiness frequent, edema, hemolytic anemia, hepatic disorders Interactions T Effects W/ anesthetics, diuretics, levodopa, Li, methotrimeprazine, thioxanthenes, vasodilators, verapamil T effects OF haloperidol, Li, tolbutamide effects W/amphetamines, Fe, phenothiazine, TCAs ... 

Temazepam (Restoril) [C-IV] [Sedative/Hypnotic/ Benzodiazepine] Uses Insomnia, anxiety, depression, panic attacks Action Benzodiaz ine Dose 15-30 mg PO hs PRN X in elderly Caution [X, /-] Potentiates CNS dqjressive effects of opioids, barbs, EtOH, antihistamines, MAOIs, TCAs Contra NAG Disp Caps SE Confusion, dizziness, drowsiness, hangover Interactions T Effects W/ cimetidine, disulfiram, kava kava, valerian T CNS depression W/ anticonvulsants, CNS depressants, EtOH t effects OF haloperidol, phenytoin X effects W/ aminophylline, dyphylline, OCPs, oxtriphylline, rifampin, theophylline, tobacco X effects OF levodopa EMS Use caution w/ other benzodiazepines, antihistamines, opioids and verapamil, can T CNS depression concurrent EtOH can T CNS depression abruptly D/C after >10 d use may cause withdrawal OD May cause profound CNS depression, confusion, bradycardia, hypotension, and altered reflexes flumazenil can be used as antidote, activated charcoal may be effective... 

Clinicians should be aware of a few drug interactions with Zolpidem. Flumazenil acts as an antagonist to the hypnotic effects of zolpidem. There is decreased alertness when zolpidem is combined with cimetidine. There is an increase in anterograde amnesia in volunteers treated with a combination of imipramine and zolpidem. Haloperidol, ranitidine, chlorpromazine, warfarin, and digoxin, along with cimetidine and flumazenil, do not alter the pharmacokinetics of zolpidem (Salva and Costa, 1995). 

Campbell, M., Anderson, L.T., Meier, M., Cohen, I.L., Small, A.M., Samit, C., and Sachar, E.J. (1978) A comparison of haloperidol and behavior therapy and their interaction in autistic childten. J Am Acad Child Psychiatry 17 640-655. 

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