Risperidone: an analysis of the first three years in general use

Since the introduction in 1993 of the novel serotonin-dopamine antagonist antipsychotic risperidone, over 12 million patient-months of exposure to the drug have been accumulated. Further studies have confirmed the efficacy of risperidone across a broad range of patients with schizophrenia who were not represented in the two pivotal clinical trials. Two studies confirm the efficacy of risperidone in first-episode schizophrenia and subanalyses of these studies suggest that the dose in these patients should be lower than in patients with chronic schizophrenia. In addition, a prospective comparison with risperidone and clozapine and a subanalysis of the North American Trial of risperidone show that risperidone is effective in treatment-resistant schizophrenia. The efficacy of risperidone against negative symptoms has been confirmed by a meta-analysis of seven clinical trials comparing risperidone with active control medication, and by further analyses of the North American Trial (analysis of covariance and path analysis). A long-term open study of risperidone has shown that the benefits of the drug extend well beyond the 8 weeks of the double-blind trials, and the low liability of risperidone for extrapyramidal side effects suggests that patients will be more likely to be compliant with risperidone treatment than with conventional neuroleptic treatment. Relapse rates can therefore be expected to be lower. Evidence from over 1100 patients, 503 of whom had taken risperidone for at least 1 year, suggests that the annual incidence of tardive dyskinesia in patients taking risperidone (7.6-9.4 mg/day) is 0.3%, compared to an annual incidence in patients taking conventional neuroleptics of 5-10%. Studies also suggest that risperidone reduces the number of days that patients with chronic schizophrenia spend as inpatients. It is concluded that mental health-care workers will need to raise their expectations about the treatment outcome of schizophrenia as a result of the introduction of risperidone.

Paroxetine potentiates the central nervous system side effects of perphenazine: contribution of cytochrome P4502D6 inhibition in vivo

BACKGROUND

Paroxetine is a frequently used antidepressant and a potent inhibitor of the CYP2D6 isozyme in vitro (inhibition constant [Ki] = 0.15 micromol/L). Most classic antipsychotic agents such as perphenazine are metabolized by the CYP2D6 isozyme and are often coadministered with antidepressant agents. This study assessed the extent of changes in CYP2D6 isozyme activity in vivo after pretreatment with paroxetine and its consequences on perphenazine kinetics and central nervous system effects.

METHODS

Eight extensive metabolizers for CYP2D6 were administered a single dose of perphenazine (0.11 mg/kg orally) or placebo following a randomized double-blind design. Perphenazine plasma concentrations and effects were assessed for a period of 8 hours. Subsequently, subjects were treated with a standard therapeutic dose of paroxetine (20 mg/day orally) for 10 days and test sessions with perphenazine and placebo were repeated.

RESULTS

Paroxetine treatment resulted in a twofold to 21-fold decrease in CYP2D6 activity (p < 0.001). After pretreatment with paroxetine, perphenazine peak plasma concentrations increased twofold to 13-fold (p < 0.01). This was associated with a significant increase in central nervous system side effects of perphenazine, including oversedation, extrapyramidal symptoms, and impairment of psychomotor performance and memory (p < 0.05).

CONCLUSION

Coadministration of perphenazine after pretreatment with a standard therapeutic dose of paroxetine increased the plasma concentration and central nervous system side effects of perphenazine, primarily as a result of inhibition of the CYP2D6 isozyme. In patients who are at steady state with paroxetine, a reduction of perphenazine dose may be required to prevent central nervous system side effects.

Long-acting injectable bromocriptine does not reduce relapse in alcoholics

Dopamine is one of several neurotransmitters that may mediate alcohol intake and dependence. A randomized, double-blind, placebo-controlled international, multicentre study was conducted to assess the effects of a long-acting injectable preparation of bromocriptine, a dopamine agonist, (Parlodel-LAR) in reducing relapse in 366 moderately/severely dependent alcoholics (DSM-III-R), drinking approximately 200 g alcohol (14.5 standard drinks) per day. After detoxification they were randomized to receive six monthly injections of bromocriptine 25 mg (n = 120), bromocriptine 50 mg (n = 124), placebo (n = 122). Brief psychosocial treatment was allowed. At 6 months there were no significant differences between treatment groups in rates of relapse to any drinking or to drinking > or = 5 days per month and > or = 3 drinks per day. Pre-treatment alcohol intake did not determine response. Efficacy ratings by subjects and investigators and adverse events, reported by 51% of subjects, did not differ between treatments. The results of this large study, in which compliance was enhanced by Parlodel-LAR, do not indicate that bromocriptine is efficacious in the maintenance of abstinence or reduced drinking. Possible reasons for the discrepancy between these conclusions and those of some previous clinical trials, in which bromocriptine was reported to reduce symptoms of alcohol withdrawal and dependence, are discussed.

Diagnosis of photosensitivity to flupenthixol by photoprick testing

We report the case of a 38-year-old patient with an erythematous eruption, initially confined to photo-exposed areas and then becoming more generalized, which was attributable to flupenthixol, a thioxanthene derivative used for its neuroleptic properties. The compound has the same polycyclic aromatic hydrocarbons as phenothiazines, but without any cross-reaction in our patient. A photoallergic cause for the eruption was verified on clinical, histological and photobiologic grounds. Photopatch tests were negative, but photoprick testing was positive after UV irradiation of the test site. Photopatch test methods using better skin penetration have been already reported for testing drug photosensitivity. Photoprick testing combines better penetration with greater ease of use.

The acute and long-term effect of olanzapine compared with placebo and haloperidol on serum prolactin concentrations

Prolactin elevation is both a common and a persistent event with the currently marketed antipsychotics, excluding clozapine. Elevations have been associated with both acute (galactorrhea, amenorrhea) and chronic (predisposition to osteoporosis) treatment-emergent adverse events. One of the defining criteria for an atypical antipsychotic is the relative lack of persistent prolactinemia. A double-blind, placebo- (N = 68) and haloperidol- (Hal: 15 +/- 5 mg/day, N = 69) controlled trial of three dose ranges of olanzapine (Olz-L: 5 +/- 2.5 mg/day, N = 65; Olz-M: 10 +/- 2.5 mg/day, N = 64; Olz-H: 15 +/- 2.5 mg/day, N = 69) in the treatment of schizophrenia afforded the opportunity to assess the temporal course of the influence of olanzapine and haloperidol on serum prolactin concentration. Consistent with its potent D2 antagonism, haloperidol was associated with a statistically significantly higher incidence of treatment-emergent prolactin elevation (72%) than seen with placebo (8%; p < 0.001) at week 2 of therapy. Expectedly, this elevation was also persistent at weeks 4 and 6. In contrast, olanzapine-associated treatment-emergent prolactin elevations were both lower in magnitude and transient. At week 2, 38% of the Olz-H, 24% of the Olz-M, and 13% of the Olz-L treatment groups exhibited a treatment-emergent prolactin elevation, with a mean increase of 0.35, 0.52, and 0.61 nmol/l, respectively; for haloperidol the mean increase was 1.23 nmol/l. For only the Olz-M and the Olz-H treatment groups did the week 2 incidence of treatment-emergent prolactin elevations differ statistically significantly from placebo. Both the incidence of elevations and the mean increase, in prolactin concentration were less than that seen with haloperidol. Furthermore, by treatment week 6, all three olanzapine groups exhibited incidences of treatment-emergent prolactin elevation that were comparable to placebo and were statistically significantly less than observed with haloperidol. Rapid adaptation was observed in the temporal course of prolactin elevations associated with olanzapine based on both the categorical analysis of treatment-emergent high values and the analyses of temporal change in mean concentrations. In contrast to haloperidol, the magnitudes of the treatment-emergent elevations associated with olanzapine were minimal. The rates of elevation were approximately one-half to one-third those observed with haloperidol and were significantly more transient. Olanzapine, even at the highest doses (15 +/- 2.5 mg/day) used, was not associated with persistent elevations of prolactin, consistent with an 'atypical' pharmacologic profile.

Intravenous chlorpromazine versus intramuscular sumatriptan for acute migraine

OBJECTIVE

To establish whether there is any difference in the efficacy of a chlorpromazine regimen and a sumatriptan regimen for the management of the pain of acute severe migraine.

SETTING

Two urban teaching hospital emergency departments.

METHODS

Prospective, randomised, unblinded, crossover trial. All patients received intravenous metoclopramide 10 mg and 1000 ml of normal saline over 1 h; 20 were then randomised to receive intramuscular sumatriptan 6 mg and 23 to receive intravenous chlorpromazine, 12.5 mg increments to a maximum of 37.5 mg. Response to treatment was measured using visual analogue pain scales.

RESULTS

No difference in efficacy between the sumatriptan regimen and the chlorpromazine regimen was found. Adverse effects were mild and equally distributed between the groups.

CONCLUSIONS

The chlorpromazine and sumatriptan regimens studied are both very effective for the relief of the headache of severe migraine.

Adenosine A2 receptors modulate haloperidol-induced catalepsy in rats

The effect of adenosine A1 and A2 receptor agonists and antagonists was investigated on haloperidol-induced catalepsy in rats. Pretreatment (i.p.) with the non-selective adenosine receptor antagonist, theophylline, or the selective adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX), significantly reversed haloperidol-induced catalepsy, whereas the selective adenosine A1 receptor antagonists, 8-phenyltheophylline and 8-cyclopentyl-1,3-dipropylxanthine produced no effect. Similar administration of the adenosine A2 receptor agonists, 5'-(N-cyclopropyl)-carboxamidoadenosine and 5'-N-ethylcarboxamidoadenosine (NECA), and the mixed agonists with predominantly A1 site of action, N6-(2-phenylisopropyl) adenosine or 2-chloroadenosine, potentiated haloperidol-induced catalepsy. Higher doses of the adenosine agonists produced catalepsy when given alone. However, N6-cyclopentyladenosine, a highly selective adenosine A1 receptor agonist, was ineffective in these respects. The per se cataleptic effect of adenosine agonists was blocked by DMPX and the centrally acting anticholinergic agent, scopolamine. Scopolamine also attenuated the potentiation of haloperidol-induced catalepsy by adenosine agonists. Further, i.c.v. administration of NECA and DMPX produced a similar effect as that produced after their systemic administration. These findings demonstrate the differential influence of adenosine A1 and A2 receptors on haloperidol-induced catalepsy and support the hypothesis that the functional interaction between adenosine and dopamine mechanisms might occur through adenosine A2 receptors at the level of cholinergic neurons. The results suggest that adenosine A2, but not A1, receptor antagonists may be of potential use in the treatment of Parkinson's disease.

Extrapyramidal symptoms in patients treated with risperidone

Data on extrapyramidal symptoms (EPS) from both arms of the North American multicenter comparative study of risperidone, placebo, and haloperidol were analyzed. The subjects were 523 patients with chronic schizophrenia who, after a 1-week washout period, received placebo, risperidone (2, 6, 10, or 16 mg/day), or haloperidol (20 mg/day) for 8 weeks; the trial was completed by 253 patients. Severity of EPS was assessed by means of the Extrapyramidal Symptom Rating Scale (ESRS). Mean changes (increases) in ESRS scores from baseline to worst score were significantly lower in each risperidone group than the haloperidol group on the total ESRS (parkinsonism + dystonia + dyskinesia), total parkinsonism, hypokinetic symptoms, and on the questionnaire (p < 0.001). On several of the subscales (dyskinesia, buccolinguomasticatory, and Clinical Global Impression severity of dyskinesia), mean change scores were significantly lower in some of the risperidone groups than in the placebo group (p < 0.05). At the clinically most effective risperidone dose (6 mg/day), the mean ESRS change score was not significantly different from that of the placebo group. A significant linear relationship was noted between mean change scores and increasing risperidone dose on 4 of the 12 ESRS subscales; nevertheless, even at 16 mg/day of risperidone, mean change scores were lower than in the haloperidol group. A linear relationship between increasing risperidone dose and use of antiparkinsonian medications was also apparent. Acute dystonic reactions occurred both in patients receiving risperidone and haloperidol. Patients with severe baseline EPS were at higher risk of EPS during the study than patients with low or moderate baseline EPS. It is concluded that low doses of risperidone cause few or no EPS and recommendations for initiation of risperidone treatment are made.

The effect of chronic oral domperidone therapy on gastrointestinal symptoms, gastric emptying, and quality of life in patients with gastroparesis

OBJECTIVE

Our aim was to determine whether domperidone could improve the symptoms of patients with gastroparesis, accelerate gastric emptying, and enhance quality of life.

METHODS

Seventeen patients (13 women, 4 men; mean age 42.9 yr) with documented gastroparesis were evaluated. A baseline gastric emptying study was performed using an isotope-labeled solid meal and a follow-up study was repeated > or =6 months after initiating domperidone therapy. The severity of nausea, vomiting, abdominal pain, and bloating were obtained at baseline and at 6-month intervals and were graded from 0 to 5 (0 = none, 5 = most severe). Also, the number of hospital admissions were noted during the study period. Patients were asked to assess their overall health status and quality of life and were begun on domperidone 20 mg q.i.d. On average, patients received domperidone for 23.3 months (range 6-48 months). Domperidone doses ranged from 40 to 120 mg daily during the study period.

RESULTS

Gastroparesis symptom scores were reduced from 4.1 +/- 0.22 (mean +/- SEM) to 1.3 +/- 0.2, and hospital admissions were decreased significantly during the study compared with before domperidone therapy (p < 0.05). At baseline, patients had a 87.3 +/- 3.71% retention of a solid meal at 2 hours compared with a 57.2 +/- 5.04% retention during domperidone therapy (p < 0.05). Domperidone treatment enhanced the quality of life in 88% of patients. The mean prolactin level was 58.9 pg/ml during the study and three patients reported gynecomastia.

CONCLUSIONS

Chronic domperidone treatment in patients with gastroparesis significantly reduced GI symptoms and hospitalizations, enhanced quality of life, and accelerated gastric emptying of a solid meal to a normal rate. Domperidone successfully treats gastroparesis on a long-term outcome basis and has an excellent safety profile.

Neuroleptic malignant syndrome with risperidone

Neuroleptic malignant syndrome is thought to be a result of dopamine D2 receptor blockade in the striatum of the basal ganglia. Risperidone, a benzisoxazole derivative antipsychotic, has high serotonin 5-HT2 receptor blockade and dose-related D2 receptor blockade. The high ratio is believed to impart the low frequency of extrapyramidal symptoms with risperidone at low dosages. With this low frequency of extrapyramidal symptoms, it was thought the frequency of neuroleptic malignant syndrome might also be lowered. A 73-year-old woman developed neuroleptic malignant syndrome after monotherapy with risperidone. The syndrome reversed after discontinuing risperidone and starting treatment with dantrolene and bromocriptine. It appears that the protection from extrapyramidal side effects observed with risperidone does not ensure protection from neuroleptic malignant syndrome.

Granisetron reduces the incidence and severity of nausea and vomiting after laparoscopic cholecystectomy

PURPOSE

Postoperative nausea and vomiting (PONV) are commonly observed undesirable consequences of laparoscopic cholecystectomy. This study was undertaken to compare granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, with droperidol for reducing the incidence and severity of PONV after laparoscopic cholecystectomy.

METHODS

Eighty patients, aged 25-65 yr, scheduled for elective laparoscopic cholecystectomy were enrolled in a randomized, double-blinded investigation and assigned to one of three treatment regimens: placebo (saline), 1.25 mg droperidol (approximately 25 micrograms.kg-1) or 3 mg granisetron (approximately 60 micrograms.kg-1). The study drugs were administered iv immediately before the induction of anaesthesia. A standard general anaesthetic technique was employed throughout. Nausea, vomiting and safety assessments were performed continuously during the first 24 hr after anaesthesia.

RESULTS

The incidence of PONV was 46% with placebo, 41% with droperidol and 15% with granisetron (P < 0.05; overall chi 2 test). Four patients who had received placebo and two who had received droperidol required another rescue antiemetic, compared with none who had received granisetron (P < 0.05). Adverse events postoperatively were not different among the groups.

CONCLUSION

Granisetron is more effective than droperidol and placebo for reducing the incidence and severity of PONV after laparoscopic cholecystectomy.

Dopamine D3-receptor gene variant and susceptibility to tardive dyskinesia in schizophrenic patients

Schizophrenia is a serious psychiatric illness with a life-time risk of approximately one percent. Many of the patients, but not all, benefit from treatment with anti-psychotic drugs known to block dopamine D2-like receptors. The use of conventional neuroleptics is, however, hampered by the risk of extrapyramidal side-effects. Tardive dyskinesia (TD) is usually regarded as the most serious of these drug-induced movement disorders due to its high prevalence and potentially irreversible nature. In this study, we have investigated the genetic variation of the dopamine D3 receptor gene (DRD3) as a putative risk factor for TD in schizophrenic patients receiving long-term anti-psychotic drug therapy. We found a high frequency (22-24%) of homozygosity for the Ser9Gly variant (allele 2) of the DRD3 gene among subjects with TD in both a cross-sectional and a longitudinal evaluation, as compared with the relative under-representation (4-6%) of this genotype in patients with no or fluctuating TD. This result indicates that autosomal inheritance of two polymorphic Ser9Gly alleles (2-2 genotype), but not homozygosity for the wild-type allele (1-1 genotype), is a susceptibility factor for the development of TD, an observation which may improve the understanding of the pathophysiological mechanisms of TD and influence the design and choice of future anti-psychotic drugs. The correlation between a serious motor side-effect and a genetic marker could lead to selection bias in the sampling of schizophrenic patients for genetic studies, and may therefore explain the apparent association reported between susceptibility for schizophrenia per se and homozygosity for the DRD3 gene.

Gynecomastia with metoclopramide use in pediatric patients

Gynecomastia and galactorrhea stemming from hyperprolactinemia have been reported in adults after the use of metoclopramide. We describe the cases of an adolescent with gynecomastia and an infant with gynecomastia and galactorrhea that were the result of metoclopramide therapy for gastroesophageal reflux disease.

Pharmacological characterization of U-101387, a dopamine D4 receptor selective antagonist

Dopamine D2-like receptors play an important role in the pharmacotherapy of psychotic disorders. Molecular and cellular techniques have identified distinct gene products (D2-long, D2-short, D3 and D4) displaying the D2 receptor pharmacology. However, the contribution of each subtype in antipsychotic effects of or their physiological role remain unclear. Here we describe the pharmacological effects of a selective D4 antagonist, U-101387. U-101387 displayed moderately high affinity (Ki = 10 nM) and selectivity for the dopamine D4.2 receptor expressed in clonal cell lines. It lacked measurable affinity for not only other dopamine receptors but also noradrenalin, serotonin and histamine receptor families (Ki > 2000 nM). It fully and dose-dependently antagonized quinpirole-induced cAMP inhibition (without producing any effect by itself) in stably transfected cells. U-101387 also displayed excellent oral bioavailability, brain penetration and other pharmacokinetic characteristics. Unlike classical neuroleptics (e.g., haloperidol), U-101387 neither blocked acute behavioral effects of amphetamine or apomorphine nor did it alter spontaneous locomotion by itself. Additionally, U-101387 was without effect in behavioral and biochemical tests predictive of extrapyramidal and neuroendocrine side effects. Consistent with the lack of autoreceptor function of D4, acute administration of U-101387 failed to alter dopamine neuronal firing by itself or reverse the inhibition produced by dopamine agonists and to affect monoamine turnover in areas innervated by the mesencephalic or hypothalamic dopamine neurons. However, U-101387 potently induced c-fos mRNA expression in the infralimbic/ventral prelimbic cortex to a level similar to that produced by the atypical antipsychotic, clozapine. This is consistent with the predominantly cortical distribution of the D4 receptor. Taken together, these results demonstrate that the D4-selective antagonist, U-101387, produces effects that are distinct from those of the nonselective D2 antagonists as well as D3-preferring agents. U-101387 offers a unique tool to understand the role of dopamine D4 receptors in diseases involving central dopamine systems.

Effects of central dopaminergic stimulation by apomorphine on swallowing disorders in Parkinson's disease

Swallowing disorders are common in Parkinson's disease but are of obscure and complex nature and pathophysiology. The effect of central dopaminergic stimulation on disordered swallowing is not well known. We studied the effects of apomorphine (in combination with domperidone) on buccolinguofacial motoricity and on various swallowing stages by using videofluoroscopy in eight patients with dysphagia. Swallowing abnormalities more frequently encountered were vallecular stasis (n = 7), fragmentation of the bolus (n = 7), and buccal stagnation of the bolus. Apomorphine improved vallecular stasis and fragmentation in about half the cases and improved buccal stagnation in all cases. Direct laryngeal penetration was found in three cases and improved in two of them. The total swallowing duration was improved by apomorphine in a subset of patients (n = 5). This improvement correlated with an improvement of the buccolinguofacial motoricity and was combined with an improvement of pharyngeal transit time. Thus central dopaminergic stimulation by apomorphine improved swallowing in a subgroup of patients, mainly in its early stages.

Tardive dyskinesia as a result of long-term prochlorperazine use

Prochlorperazine is a centrally acting dopamine receptor antagonist that is most commonly used for the treatment of nausea and vomiting. Like many dopamine antagonists, prochlorperazine has the ability to induce extrapyramidal reactions in susceptible patients. Rarely, however, have cases of tardive dyskinesia been caused by the long-term use of this agent. We report the case of a patient who used prochlorperazine for a prolonged period and, during hospital admission, was found to have a new movement disorder. Alternative antiemetics that do not pose a risk of movement disorders, such as ondansetron and granisetron, are readily available and are efficacious.

Drugs inducing or aggravating parkinsonism: a review

Drug-induced parkinsonism (DIP) is frequent. The list of drugs able to induce parkinsonism is long and probably incomplete, because new drugs, with previously unknown antidopaminergic activity, are constantly being added. Not all the drugs have the same potency for inducing parkinsonism. We classify these drugs in three groups: (1) drugs with obvious antidopaminergic activity which regularly induce parkinsonism; (2) drugs able to induce parkinsonism in particular individuals and (3) drugs which may aggravate Parkinson's disease treated with levodopa. The reports of isolated cases of parkinsonism induced by widely-used drugs (drugs in group 2) may be the result of either an idiosyncratic side effect or a misdiagnosis of parkinsonism. The antidopaminergic activity of the drugs of this group is weak and not sufficiently demonstrated. Maybe, in these cases, the blockage of other neurotransmitters different from dopamine plays a role in the induction of parkinsonism. Probably, the number of patients with DIP is higher than reported or detected, because many patients suffer from weak symptoms that quickly disappear after drug withdrawal. One of the main points of interest is knowing the list, because all these drugs, specially those of group 1, should be avoided or used with caution in the treatment of some common symptomatic problems in patients with Parkinson's disease, such as depression, arterial hypertension, diabetes mellitus and cardiac disorders. The precautions should extent to other populations especially susceptible to suffer from DIP, such as the elderly or patients with other neurodegenerative disorders, such as Alzheimer's disease.

Omeprazole versus ranitidine or ranitidine/metoclopramide in poorly responsive symptomatic gastroesophageal reflux disease

OBJECTIVES

To evaluate complete symptom resolution, mucosal healing, and tolerability of omeprazole, ranitidine, or ranitidine/metoclopramide in patients with poorly responsive, symptomatic gastroesophageal reflux disease (GERD).

METHODS

Adults with persistent symptomatic GERD after ranitidine treatment were stratified by esophagitis grade and randomized to omeprazole 20 mg once daily, ranitidine HCI 150 mg twice daily, or ranitidine HCI 150 mg twice daily plus metoclopramide HCI 10 mg four times daily. Endoscopies were conducted at baseline and at wk 4 and 8. Patients assessed overall symptom improvement at wk 4 and 8 and evaluated daytime and nighttime heartburn, dysphagia, and acid regurgitation daily.

RESULTS

After 1 wk, 13% of patients receiving omeprazole (N = 100) had complete resolution of all GERD symptoms versus 1% and 3% of patients receiving ranitidine (N = 97) or ranitidine/metoclopramide (N = 93), respectively (p < 0.001). More patients receiving omeprazole had complete symptom resolution at wk 4 (33%) and at the end of the study (64%; both p < 0.001) than patients receiving ranitidine (8% and 28%, respectively) or ranitidine/metoclopramide (7% and 29%, respectively). Regardless of baseline esophagitis grade, more patients receiving omeprazole had complete symptom resolution. At wk 8, more than 91% of patients with grade 0 or 1 esophagitis at baseline were still healed irrespective of treatment. At wk 8, 80% of patients with esophagitis grade 2 or higher at entry were healed with omeprazole (p < 0.001 vs ranitidine [40%] and ranitidine/metoclopramide [46%]). Thirty-four percent of patients reported an adverse event. Significantly more patients receiving combination treatment reported an adverse event than patients treated with single agents.

CONCLUSIONS

In patients with persistent GERD symptoms after ranitidine, omeprazole (20 mg daily for up to 8 wk) provides faster and more complete resolution of common GERD symptoms than continued ranitidine (300 mg daily) alone or in combination with metoclopramide (40 mg daily). Omeprazole provides significantly higher rates of endoscopic healing than ranitidine alone or with metoclopramide. Omeprazole and ranitidine are generally well tolerated. The addition of metoclopramide to ranitidine significantly increases adverse events.

A risk-benefit assessment of drugs used in the management of obsessive-compulsive disorder

Established efficacy and tolerability in large multicentre controlled studies have made serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors (SRIs) the mainstay of monotherapy for adult obsessive-compulsive disorder (OCD). When compared with the selective serotonin reuptake inhibitors (SSRIs), the tricyclic compound clomipramine has a higher incidence of adverse effects but is well tolerated by most OCD patients and may confer the best overall antiobsessional effects. Consideration of specific adverse effect profiles, special patient population characteristics, drug interactions and relative cost of the various agents may direct clinicians in choosing the most appropriate first-line drug. Alternative agents as monotherapies have been explored, but none has consistently proven effective to date. Investigations of SRI augmentation with serotonin-enhancing agents have also failed to demonstrate substantial benefits for treatment-refractory OCD. Combination treatment with SRIs and dopamine receptor antagonist drugs appears to provide an improved response for the subpopulation of OCD patients who have comorbid 'tic-spectrum' disorders, though large-scale studies of the efficacy and tolerability of these regimens are not yet available.

Cardiorespiratory, endocrine and metabolic changes in ponies undergoing intravenous or inhalation anaesthesia

Six Welsh gelding ponies (weight 246 +/- 6 kg) were premedicated with 0.03 mg/kg of acepromazine intravenously (i.v.) followed by 0.02 mg/kg of detomidine i.v. Anaesthesia was induced with 2 mg/kg of ketamine i.v. Ponies were intubated and lay in left lateral recumbency. On one occasion anaesthesia was maintained for 2 h using 1.2% halothane in oxygen. The same group of ponies were anaesthetized 1 month later using the same induction regime and anaesthesia was maintained with a combination of detomidine, ketamine and guaiphenesin, while the ponies breathed oxygen-enriched air. Electrocardiogram, heart rate, mean arterial blood pressure, cardiac output, respiratory rate, blood gases, temperature, haematocrit, glucose, lactate and cortisol were measured and cardiac index and systemic vascular resistance were calculated in both groups. Beta-endorphin, met-enkephalin, dynorphin, arginine vasopressin (AVP), adrenocorticotrophic hormone (ACTH) and catecholamines were measured in the halothane anaesthesia group only and 11-deoxycortisol during total intravenous anaesthesia (TIVA) only. Cardiorespiratory depression was more marked during halothane anaesthesia. Hyperglycaemia developed in both groups. Lactate and AVP increased during halothane anaesthesia. Cortisol increased during halothane and decreased during TIVA. There were no changes in the other hormones during anaesthesia. Recovery was smooth in both groups. TIVA produced better cardiorespiratory performance and suppressed the endocrine stress response observed during halothane anaesthesia.

[Pharmacologic and clinical differentiation of prokinetic drugs]

In the treatment of gastrointestinal motility disorders 3 prokinetic agents are principally available. They are differentiated from their pharmacological mode of action, their clinical efficacy and tolerability. Metroclopramide is an antidopaminergic benzamide with mainly antiemetic effects and minor prokinetic efficacy in the GI-Tract. Domperidon is a pure dopaminantagonist. It accelerates gastric emptying but has less effect on bowel motility. Cisapride stimulates indirect the secretion of acetylcholine and acts via 5 HT-receptors selective at the plexus myentericus. These pharmacological differences have clinical relevance: metoclopramide and domperidon could not consistently prove efficacy in functional dyspepsia and GORD. In addition the data in other indications are rare. Only cisapride has shown significant responder rates in controlled studies in the treatment of gastrointestinal motility disorders particularly in long term treatment. As concerns tolerability cisapride presents a progress by its selective mode of action in contrast to the agents crossing the blood-brain-barrier.

Optimal control of acute cisplatin-induced emesis

A survey by Coates and co-workers in 1983 revealed that patients ranked nausea and vomiting as the most distressing side effects of chemotherapy. In the last decade the use of high-dose metoclopramide and, especially, the introduction of the 5-HT3 receptor antagonists, have been major leaps forward in the control of chemotherapy-induced emesis. Nevertheless, since patients still consider nausea and vomiting to be the most distressing side effect of their chemotherapy there is clearly a need for further improvements. Acute emesis, which is the topic of this review, can now be controlled in the majority of patients during their first course of chemotherapy. Future focus should be on better control of emesis during subsequent courses of chemotherapy as well as on better control of delayed emesis.

Serotonin-2 and dopamine-1 binding components of clozapine in frontal cortex and striatum in the human brain visualized by positron emission tomography

The specific binding of N-methyl-11C-clozapine in the human brain was studied in five healthy volunteers with positron emission tomography (PET). Four of the volunteers were reexamined after treatment with the dopamine D1 and D2 receptor antagonist flupenthixol, and all five volunteers were reexamined after pretreatment with the serotonin2 receptor antagonist ritanserin. The examinations after flupenthixol and ritanserin treatment were performed on different occasions. In the flupenthixol part of the study, two of the subjects were given an oral dose of 1 mg flupenthixol 2-3 h before the posttreatment study with PET. The other two subjects received 0.5 mg orally three times during the 24 h preceding the posttreatment PET study, with the last dose being administered < or = 4 h before the scan. All five ritanserin-treated subjects followed the same dosing regimen. During the 5 days preceding the posttreatment PET study, they were given a 10-mg tablet of ritanserin in the evening. The last dose was administered 2-1/2 hours before the study. Both flupenthixol and ritanserin pretreatment were associated with decreased binding of N-methyl-11C-clozapine in dorsolateral and medial frontal cortical regions. These results support previous findings that clozapine has affinity for both dopamine D1 and serotonin 5-HT2 receptors in the human frontal cortex. No consistent change of binding was observed in striatal regions following flupenthixol or ritanserin pretreatment. The clinical aspects of this feature are discussed, both with respect to efficacy and side effects.

Effect of the putative dopamine D1 agonist and D2 antagonist FCE 23884 on Parkinson's disease

The ergoline derivative FCE 23,884 acts as a dopamine D1 agonist in untreated parkinsonian animals and as a D2 antagonist in animals whose dopamine system is intact or levodopa treated. To evaluate whether this dual action might benefit patients with Parkinson's disease (PD) who have developed levodopa-induced dyskinesias, the motor effects of FCE 23,884 were examined in seven such individuals using a double-blind, placebo-controlled design. At doses up to the maximum tolerated dose (3.5 +/- 0.5 mg), FCE 23,884 monotherapy did not affect parkinsonian severity. On the other hand, coadministration of FCE 23,884 with a mildly dyskinetic dose of levodopa, infused intravenously under steady-state conditions, reduced the antiparkinson response by 54 +/- 19% and tended to diminish dyskinesia severity. The results thus fail to suggest any useful role for FCE 23,884 in the symptomatic treatment of PD. Although D2 receptor blockade provided by FCE 23,884 antagonizes both the antiparkinson and dyskinesigenic responses to levodopa, the degree of D1 receptor stimulation appears insufficient to ameliorate parkinsonian symptomatology.

Efficacy and safety of risperidone in psychotic patients: an open study

This open prospective study was undertaken to determine the efficacy and safety of a fixed dose (6 mg) of risperidone in psychotic patients. Hospital in-patients who fulfilled DSM-111-R criteria for schizophrenia, schizoaffective and bipolar disorders were eligible for entry into the study (n = 15). Patients who were on other antipsychotics had a washout period of 1 week before they were started on the drug. A fixed dose of risperidone was administered (6 mg). The Brief Psychiatric Rating Scale (BPRS), Negative Symptom Rating Scale (NSRS) and Abnormal Involuntary Movement Scale were used to measure psychopathology and extrapyramidal side-effects. Five patients dropped out of the study. Two patients became very agitated and potentially aggressive, one patient became very restless and did not respond to benzodiazepines, and one dropped out because of restlessness that did not respond to clonazepam. Of the 10 patients who completed the study, 50 per cent reduction on BPRS and NSRS was achieved by five and six patients respectively. There was a marginally significant trend towards a greater reduction in the magnitude of negative symptoms. Four patients required treatment with anticholinergic drugs. Risperidone was effective in resistent psychotic patients, but agitated and impulsive psychotic patients with positive symptoms may not be best candidates for treatment with risperidone. On average, negative symptoms respond better than positive symptoms.

Neuroleptic malignant syndrome

Neuroleptic malignant syndrome is a rare, idiosyncratic condition related to neuroleptic use which may develop at any stage during neuroleptic treatment and can prove fatal. Although most commonly seen in psychiatric patients, anyone prescribed a neuroleptic is at risk and it has been associated with other agents. This article discusses its recognition, risk factors, clinical course and treatment, together with a summary of current thinking on its aetiology.

Extrapyramidal symptoms during long-term treatment with antipsychotics: special focus on clozapine and D1 and D2 dopamine antagonists

In schizophrenic patients in maintenance treatment, clozapine, compared to classic neuroleptics, induces relatively few extrapyramidal syndromes (EPS), especially less akathisia and tremor and usually no dystonia or rigidity. In patients with dyskinetic movements (acute or tardive) induced by other neuroleptics, clozapine may reduce or even remove dyskinesia or permit it to disappear. It cannot, however, be excluded that clozapine can induce dyskinesia in extremely rare cases, but it seems more likely that this is due to previous treatment with classic neuroleptics. The earlier clozapine is started, the less chance of development of dyskinesia. The low level of EPS with clozapine may be linked to the special receptor-binding profile of this drug: during treatment with therapeutic doses of clozapine, the level of D2 receptor blockade is too low (40% to 50% occupancy by positron emission tomography) to induce EPS, and the D1 receptor blockade (also 40% to 50% occupancy) has a lower EPS potential than D2 blockade. This binding profile may at the same time contribute to the special antipsychotic properties of clozapine. Other receptor affinities may contribute to the beneficial effect of clozapine in EPS and schizophrenia.

Metoclopramide exaggerates stress-induced tachycardia in pregnant sheep

Metoclopramide is often administered to hasten gastric emptying prior to cesarean section and during labor, but has also been demonstrated to increase catecholamine release during stress and to increase heart rate and blood pressure in nonpregnant humans. The purpose of this study was to examine the maternal and fetal effects of metoclopramide during maternal stress in pregnant ewes. After baseline measures, eight ewes were randomly allocated to receive either intravenous metoclopramide, 10 mg, or saline, followed in 10 min by nonpainful stress to increase mean arterial pressure 40%-45% for 30 s. At least 2 days later, the ewes received the alternate treatment. Metoclopramide, but not saline, increased resting maternal heart rate. In the 10 min after maternal stress, maternal heart rate was increased more after metoclopramide than after saline treatment, whereas maternal blood pressure, uterine blood flow, and fetal hemodynamic variables and arterial blood gas tensions did not differ between the two treatments. Whereas these results are not consistent with a generalized increase in sympathetic nervous system tone after a single dose of metoclopramide, they do suggest that metoclopramide may exaggerate tachycardia after stress, encountered frequently both during and after cesarean section.

Pathophysiology of schizophrenia and the role of newer antipsychotics

Schizophrenia is an illness with numerous neurobiologic features. It is hypothesized that patients may have a relative deficit of dopamine neurotransmission in the nigrostriatal and mesocortical tracts of the brain, as contrasted with an excess of dopamine neurotransmission in the mesolimbic area. The dopamine deficit may be related to the negative symptoms (blunted affect, anhedonia, asociality, inability to initiate and carry out complex tasks to completion) of schizophrenia, whereas the dopamine excess may be responsible for the positive symptoms (hallucinations, delusions, and thought disorder). Compared with healthy subjects, schizophrenic patients may also have increased levels of serotonin and decreased levels of norepinephrine in the brain. Conventional antipsychotic drugs nonselectively block dopamine D2 receptors throughout the central nervous system. This may help reduce positive symptoms, but has little or no effect on negative symptoms. Newer agents have more anatomically selective activity with respect to dopaminergic systems but are more complex with respect to their actions in other neurochemical systems, such as serotonin and norepinephrine, which presumably contributes to their apparent greater therapeutic efficacy.

[Calcium carbasalate-metoclopramide combination versus dihydroergotamine in the treatment of migraine attacks]

In this randomised, double-blind, cross-over study the association of calcium carbasalate+metoclopramide was compared with oral dihydroergotamine mesilate in the treatment of migraine attacks. 155 patients suffering from migraine, with or without aura were analysed; the main efficacy criteria being the evolution of the headache intensity: disappearance of headache 2 hours after administration or incomplete improvement (severe to moderate headache reduced to slight headache). There was a significantly greater reduction in headache intensity following administration of CSC-METO (p < 0.001), the percentage of patients showing recovery or improvement two hours after administration being 64.5% with CSC-METO compared to 43.5% with DHE. A significantly more marked improvement following administration of CSC-METO was also observed for nausea, photophobia, phonophobia, use of analgesic treatment, impact on normal activities and overall assessment by the patient and physician. The frequency of undesirable events was weak and identical for both treatments.

Evaluation of SCH 39166 as PET ligand for central D1 dopamine receptor binding and occupancy in man

SCH 39166 is the first selective D1-dopamine receptor antagonist developed for clinical trials in schizophrenia. SCH 39166 was evaluated as a radioligand for PET, labeled with 11C, and as a D1-dopamine receptor antagonist after single oral doses in healthy men. After intravenous injection of [11C]SCH 39166 distribution of radioactivity in brain grossly reflected D1-dopamine receptor density. The putamen to cerebellum ratio at equilibrium was low (1.54 +/- 0.18 SD), which makes [11C]SCH 39166 less suitable as a radioligand for applied PET studies. Saturability of specific binding was demonstrated after IV injection of [11C]SCH 39166 with low specific radioactivity. Stereospecificity of binding was examined using the stereoisomer [11C]SCH 39165. D1-Receptor occupancy was demonstrated with [11C]SCH 39166 2 h after administration of single oral doses of unlabeled SCH 39166 to each of three healthy subjects (25, 100 and 400 mg). There was a substantial reduction of specific [11C]SCH 39166 uptake in the putamen after all doses. Single oral doses of 100 mg induced approximately 70% D1-dopamine receptor occupancy in the basal ganglia, which should be sufficient to investigate the antipsychotic potential of D1-dopamine receptor antagonism in clinical studies.

DL-tetrahydropalmatine-produced hypotension and bradycardia in rats through the inhibition of central nervous dopaminergic mechanisms

The effects of DL-tetrahydropalmatine (THP; a main active substance of the Chinese herb corydalis), haloperidol (a dopamine D2 receptor antagonist), apomorphine and amphetamine on cardiovascular function and striatal dopamine (DA) release were compared in rats under general anesthesia. Intravenous administration of THP (1-10 mg/kg) or haloperidol (0.5-1.25 mg/kg) produced hypotension, bradycardia and increased DA release in the striatum. On the other hand, amphetamine (0.5-1.25 mg/kg) produced hypertension, tachycardia and increased striatal DA release. However, intravenous injection of apomorphine (0.5-1.25 mg/kg) produced hypotension, bradycardia and decreased striatal DA release. In addition, the THP-induced hypotension was attenuated by pretreatment with spinal transection or amphetamine, while the THP-induced bradycardia was attenuated by pretreatment with bilateral vagotomy or amphetamine. Thus, it appears that THP acts through DA D2 receptor antagonism to induce hypotension and bradycardia in rats.

Lack of apparent antipsychotic effect of the D1-dopamine receptor antagonist SCH39166 in acutely ill schizophrenic patients

SCH 39166 is the first selective D1 dopamine receptor antagonist developed for the treatment of schizophrenic patients. To examine potential antipsychotic effect, tolerability and safety, SCH 39166 was given orally to 17 acutely ill drug free schizophrenic patients (DSMIIIR) in an open 4-week study. Doses were escalated from 10 to 100 mg b.i.d. according to a fixed schedule over 17 days and remained at 100 mg b.i.d. for another 11 days. The drug was withdrawn prematurely in ten patients because of deterioration or refusal to take SCH 39166. In the nine patients participating for more than 2 weeks, none had an apparent reduction of BPRS or CGI scores. Side effects were agitation, akathisia and emesis in single patients. After withdrawal of SCH 39166 of the patients improved when treated with classical neuroleptics or clozapine. The result of the study does not support the prediction that selective D1 dopamine receptor antagonism will produce antipsychotic effects in schizophrenia.

Two cases of mequitazine-induced photosensitivity reactions

Mequitazine is a phenothiazine derivative antihistamine. We experienced 2 cases of mequitazine-induced photosensitivity reaction in patients who took mequitazine for their dermatologic problems. Case no. 1 showed features of photoallergy such as 1-month incubation period, decreased MED to UVA, strong positive photopatch test result, cross reaction to chlorpromazine, and angry back phenomenon found in allergic contact dermatitis. In addition, an immediate erythematous macule was observed on the photopatch test site of mequitazine directly after UV exposure which was similar to the immediate erythema noted in chlorpromazine photoallergy. During the follow-up period of two months, there was transiently decreased MED to UVB, which became normalized after 1 month treatment with cyclophosphamide. In case no. 2, the pathogenic mechanism seemed to be persistent light reaction preceded by systemic photoallergy, as he had taken mequitazine for 6 months, and there were strong positive photopatch test results with immediate erythema reaction, cross-reaction to promethazine, decreased MED to both UVA and UVB, and persistence of the photosensitivity over a 3-year follow-up period after discontinuation of the mequitazine. Photopatch tests to 1% mequitazine with 5 J/cm2 of UVA in 30 normal subjects were all negative, which means that 1% concentration may be appropriate for the photopatch test. Mequitazine seemed to play a part similar to chlorpromazine, and absence of mequitazine-induced photosensitivity may be due to a relatively low dosage of the drug. However, dermatologists should be cautious about a photosensitivity reaction induced by mequitazine or other phenothiazine-derivative drugs.

[Psychiatric drugs as risk factor in fatal heat stroke]

Two men aged 33 and 31 years suffered a fatal heat stroke on a warm summer day. One of them used pimozide and clomipramine, the other zuclopenthixol, dexetimide, droperidol, promethazine and propranolol as psychiatric medication. Both of them had a body temperature > 42.3 degrees C, without perspiring. At first only a comatose situation with practically normal laboratory values existed; this was rapidly followed by massive liver damage, disseminated intravascular coagulation, anaemia, thrombopenia and acute renal failure. In spite of adequate and rapid treatment these complications were fatal. Both patients used medication with an antidopaminergic and anticholinergic (side) effect. The set point of the temperature regulation centre can be elevated by the antidopaminergic activity of antipsychotics. Use of anticholinergic medication can disturb the thermoregulation via inhibition of the parasympathicomimetically mediated sweat secretion. It is recommended to point out the danger of unusually high outdoor temperatures to patients using this medication.

Intravenous chlorpromazine vs intravenous metoclopramide in acute migraine headache

OBJECTIVE

To compare the efficacy of IV chlorpromazine with that of IV metoclopramide in the treatment for acute migraine headache in the ED.

METHODS

A prospective randomized double-blind trial was undertaken at two university-affiliated urban EDs with a combined annual census of more than 85,000 patients. Included in the study were patients presenting to the ED with a diagnosis of migraine headache. The subjects were randomized to receive 0.1 mg/kg/dose IV of either chlorpromazine (CPZ) or metoclopramide (MC), up to a total of three doses.

RESULTS

Ninety-one patients completed the protocol; 44 received MC and 47 received CPZ. The demographics of the two groups were similar. Both drugs provided, for the majority of patients, adequate pain relief as measured on a visual analog scale (VAS) completed every 15 minutes from T = 0 minutes to T = 45 minutes. The average pain relief over 45 minutes (delta VAS) for CPZ was 4.87 cm, vs 4.34 cm for MC (p = 0.35). There also was no statistically significant difference in blood pressure (BP) changes (delta BP < 2 mm Hg for both systolic and diastolic BPs, p = 0.47 and 0.33) or numbers of patients reporting adverse effects (AEs) (CPZ: 16 of 35; MC: 13 of 29, p = 0.43). There was no severe AE with either study drug.

CONCLUSIONS

Metoclopramide and chlorpromazine administered IV are both effective in the management of acute migraine headache. They are associated with similar minor side-effect profiles.