Haloperidol adverse effects

On the whole significant interactions between the antipsychotics and SSRIs appear rare (although see thioridazine, below). The combination can be useful and so the isolated cases of extrapyramidal adverse effects should not prevent concurrent use. However, if extrapyramidal effects become troublesome bear this interaction in mind as a possible cause. The significance of the rise in haloperidol levels caused by fluoxetine and fluvoxamine is unclear, be aware that haloperidol adverse effects may be increased in some patients and consider reducing the haloperidol dose if problems occur. The rise in perphenazine levels caused by paroxetine seems to result in a greater number of more serious adverse effects and so consideration should be given to reducing the dose of perphenazine if paroxetine is started. Citalopram may be a suitable alternative as it does not appear to affect perphenazine levels. 

The evidence is very limited but be aware that increased haloperidol adverse effects may occur if venlafaxine is also given. It may be necessary to reduce the haloperidol dosage. 

Pimozide is FDA-labeled for Tourette s disorder and is particularly interesting in that it is a highly specific DA antagonist that may produce fewer adverse effects than haloperidol. In open studies with adequate doses, this agent has demonstrated efficacy for acute schizophrenia. Several double-blind trials comparing pimozide with other neuroleptics also found it to be an equally effective maintenance therapy ( 34, 35, 36, 37 and 38). We consider this agent to be as effective as the other standard agents, with the same, but perhaps less severe, side effects. 

Clinically, haloperidol decanoate has been administered to hundreds of chronic schizophrenic patients in several open studies to determine its efficacy, pharmacokinetics, safety, and adverse effects. The trials ranged from 4 months to 2 years, with dosages ranging from 25 to 500 mg given once every 4 weeks. The results of these studies have consistently shown that depot haloperidol ... 

Kissling et al. (27,9) evaluated both fluphenazine and haloperidol decanoate in a 6-month double-blind study involving 31 schizophrenic patients. These authors found both were equally effective in preventing relapse, with a slight advantage for haloperidol decanoate as reflected by fewer adverse effect-related dropouts and a decreased need for antiparkinsonian medications with this latter agent. Wistedt ( 280) compared fluphenazine decanoate with haloperidol decanoate in a double-blind... 

Kissling W, Moller HJ, Walter K, et al. Double-blind comparison of haloperidol decanoate and fluphenazine decanoate effectiveness, adverse effects, dosage and serum levels during a six months treatment for relapse prevention. Pharmacopsychiatry 1985 18 240-245. 

Nevertheless, this condition is responsive to treatment with dopamine-2 receptor antagonists. Hence, this condition is one of the clearest childhood indications for treatment with these medications. In theory, any dopamine-2 blocking receptor antagonist could be used. Haloperidoi has been the most extensively tested and used medication for this condition (167). The typical dose for children aged 3 to 12 years old is 0.2 mg/kg per day. More recently, in a double-blind study of 36 boys with Tourette s syndrome, risperidone was effective in reducing tics in 88% versus 60% for haloperidol (197), perhaps making risperidone a better option than a neuroleptic in terms of neurological adverse effects. 

Pimozide is an alternative agent for refractory cases or those unable to tolerate haloperidol. In a double-blind, crossover study, pimozide was superior to both haloperidol and placebo (198), in part because of the higher rate of treatment-limiting adverse effects of haloperidol versus pimozide (41% versus 14%). 

Haloperidol Blockade of D2 receptors >> 5HT2A receptors Some a blockade, but minimal M receptor blockade and much less sedation than the phenothiazines Schizophrenia (alleviates positive symptoms), bipolar disorder (manic phase), Huntington s chorea, Tourette s syndrome Oral and parenteral forms with metabolism-dependent elimination Toxicity Extrapyramidal dysfunction is major adverse effect... 

Dicyclomine (Bentyl) [Anrimuscarinic, GI Anrispasmodic/ Anticholinergic] Uses Functional IBS Action Smooth-muscle relaxant Dose Adults. 20 mg PO qid T to 160 mg/d max or 20 mg EM q6h, 80 mg/d - qid then T to 160 mg/d, max 2 wk Feds. Infants >6 mo 5mg/dose tid-qid Children 10 mg/dose tid-qid Caution [B, -] Contra Infants <6 mo, NAG, MyG, severe UC, BOO Disp Caps, tabs, syrup, inj SE Anticholinergic SEs may limit dose Interactions T Anticholinergic effects W/ anticholinergics, antihistamines, amantadine, MAOIs, TCAs, phenothiazides T effects OF atenolol, digoxin X effects H7 antacids X effects OF haloperidol, ketoconazole, levodopa, phenothiazines EMS Avoid procainamide usage, may T adverse effects may T effects of digoxin, monitor... 

A 29-year-old woman with a schizoaffective disorder took haloperidol 5 mg/day and then 9 mg/day because of acute psychotic episodes. She had no adverse effects such as amenorrhea or galactorrhea. Haloperidol was then replaced by aripiprazole 15 mg/day and on the evening of the second day she developed breast tenderness and marked galactorrhea. The serum prolactin concentration was 32 ng/ml (reference range 5-25 ng/ ml). Aripiprazole was withdrawn and haloperidol restarted. The galactorrhea resolved in 1 week. 

Multiple sites in the CNS are affected by LSD. The drug shows serotonin (5-HT) agonist activity at presynaptic receptors in the midbrain, binding to both 5-HT and 5-HT2 receptors. Activation of the sympathetic nervous system occurs, which causes pupillary dilation, increased blood pressure, piloerection, and increased body temperature. Taken orally, low doses of LSD can induce hallucinations with brilliant colors, and mood alteration occurs. Tolerance and physical dependence have occurred, but true dependence is rare. Adverse effects include hyperreflexia, nausea, and muscular weakness. Sometimes high doses produce long-lasting psychotic changes in susceptible individuals. Haloperidol (see p. 127) and other neuroleptics can block the hallucinatory action of LSD and quickly abort the syndrome. 

Erythrocyte/plasma lithium concentration ratios were lower in patients taking phenothiazines or haloperidol than in those taking lithium alone (620,621), and the former group had a higher incidence of neurological and renal adverse effects (621). 

Fixed doses of amisulpride (100, 400, 800, and 1200 mg/ day) and haloperidol (16 mg/day) have been compared in a 4-week, double-blind, randomized trial in 319 patients with acute exacerbations of schizophrenia (33). Amisulpride 400 mg/day and 800 mg/day was effective in treating the positive symptoms of schizophrenia, with fewer extrapyramidal adverse effects than haloperidol,... 

Clinical predictors of response to clozapine have been examined in 37 partially treatment-refractory outpatients who had been assigned to clozapine in a double-blind, haloperidol-controlled, 29-week study (50). Clozapine responders were rated as less severely ill, had fewer negative symptoms, and had fewer extrapyramidal adverse effects at baseline compared with non-responders. 

---