Torsion dystonia: a double-blind, prospective trial of high-dosage trihexyphenidyl

We studied trihexyphenidyl in the treatment of torsion dystonia in a prospective, double-blind crossover protocol. Thirty-one patients completed the protocol. Twenty-two (71%) had a clinically significant response. After a mean follow-up of 2.4 years, 68% of patients continued to take trihexyphenidyl, and 42% continued to show a considerable or dramatic benefit. The 30-mg dose used was generally well tolerated. High-dosage trihexyphenidyl therapy is effective in the management of torsion dystonia.

Botulinum toxin versus trihexyphenidyl in cervical dystonia: a prospective, randomized, double-blind controlled trial

BACKGROUND

Botulinum toxin type A (BTA) is replacing trihexyphenidyl as the treatment of choice for idiopathic cervical dystonia (ICD), but there has never been a direct comparative study.

METHODS

This trial compares the effectiveness of BTA with that of trihexyphenidyl in a prospective, randomized, double-blind design. Sixty-six consecutive patients with ICD were randomized to treatment with trihexyphenidyl tablets plus placebo injection or placebo tablets plus BTA injections. Tablets were administered daily according to a fixed schedule. Dysport or saline was injected under EMG guidance at study entry and again after 8 weeks. Patients were assessed for efficacy at baseline and after 12 weeks by different clinical rating scales.

RESULTS

Sixty-four patients completed the study, 32 in each group. Mean dose of BTA was 292 mouse units (first session) and 262 mouse units (second session). Mean dose of trihexyphenidyl was 16.25 mg. The changes on the Disability section of the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS-Disability) (primary outcome), Tsui Scale, and the General Health Perception Subscale were significantly in favor of BTA. More patients treated with BTA had an improvement of at least three points on the TWSTRS-Disability (14 versus 6) and on the Tsui Scale (23 versus 12). Adverse effects were significantly less frequent in the BTA group.

CONCLUSION

BTA is significantly more effective in the treatment of ICD, with less adverse effects.

Dopa-responsive dystonia: long-term treatment response and prognosis

We report observations on the treatment of 66 patients with presumed dopa-responsive dystonia (DRD). Forty-seven of these patients had hereditary disease; 19 had disease of sporadic occurrence. Initial diagnostic confusion with "cerebral palsy" or "spastic diplegia" existed in 16 patients. Several patients benefited from anticholinergic medications and a few from carbamazepine. Levodopa was the most effective treatment in all cases. In the majority, there was an excellent response, with continued long-term clinical stability on levodopa therapy for as long as 10 to 22 years. Four men with sporadic disease and 1 woman with a sister affected with adolescent-onset parkinsonism had similar initial treatment response, but developed "wearing-off" and a less satisfactory response to levodopa within the first few years of treatment. This indicates that some patients with clinical syndromes suggestive of DRD may not have an excellent prognosis on long-term levodopa treatment and may represent misclassified cases of childhood-onset parkinsonism.

Psychiatric symptoms during l-dopa therapy for Parkinson's disease and their relationship to physical disability

Fifty patients attending a neurological outpatient clinic for Parkinson's disease were assessed by standardized methods for both physical and psychiatric symptoms. The patients then received treatment with L-dopa with carbidopa or anticholinergic drugs and/or amantadine. During the following six-month period the subjects were assessed at intervals, both physically and psychiatrically. Forty patients were followed up for the full six-month period. The severity of physical signs and affective symptoms was shown to be significantly related at several stages of the investigation. Initially, the patients showed a high psychiatric morbidity. During treatment, 22 patients developed a depressive disorder, 12 or which had a history of previous depressive episodes. By contrast, of the 11 patients who showed very few affective symptoms during follow-up, none had a history of depression. Of the 22 patients with a depressive disorder, only two were in the anticholinergic/amantadine group, compared with nine and 11 in the other groups. L-dopa was not an effective antidepressant agent. The probable relevance of the findings of the study to the management of patients with Parkinson's disease is outlined.

Relationships between medication treatments and neuropsychological test performance in schizophrenia

Few investigations have assessed the neuropsychological effects of psychotropic medications on schizophrenic patients. In this study, 44 clinically stable schizophrenic inpatients were administered a battery of neuropsychological tests, and their performance was correlated with dosage of neuroleptic medication and benztropine. Neuroleptic dose was correlated with poorer performance on tests of psychomotor speed and attention, and with the number of perserverative errors on the Wisconsin Card Sort. Anticholinergic dose was associated with poorer verbal learning, verbal fluency, and motor speed. Both medication dosages were associated with poorer verbal recognition memory, but this association was strongly influenced by the performance of individuals on the highest medication doses. The findings, which were independent of clinical state and intelligence, indicate that higher doses of neuroleptic and anticholinergic medications are associated with poorer neuropsychological functioning in schizophrenia.

Single case study. Possible organophosphate-induced parkinsonism

A case of possible organophosphate-induced parkinsonism is presented. The patient was a crop duster with numerous episodes of acute organophosphate intoxication and chronic organophosphate exposure. The etiology of parkinsonism is discussed in terms of a balance hypothesis between cholinergic and dopaminergic neurotransmission in the striatum. A possible relationship between chronic organophosphate exposure and alterations in central cholinergic or dopaminergic activity is suggested. The course of this patient raises the possibility that agricultural workers may be at risk for the late development of parkinsonism.

Adverse effects of antiparkinson drug withdrawal

The authors conducted a double-blind, controlled study to test the behavioral, affective, and neurological effects of antiparkinson drug discontinuation. Patients were evaluated at baseline and at 2 and 4 weeks. Of 24 placebo patients 9 left the study early because of adverse effects; none of the 8 patients in the antiparkinsonian group did so. The placebo group had significantly more lower extremity movements, motor agitation, hallucinations, and physical complaints at 2 weeks and scored significantly higher in depression at 4 weeks. A sizable proportion of chronic, drug-treated schizophrenic patients appear to need antiparkinsonians for clinical stability.

Acute and long-term administration of anticholinergics in Parkinson's disease: specific effects on the subcortico-frontal syndrome

Parkinson's Disease (PD) is often associated with a subcortico-frontal syndrome (SCFS) that is mainly characterized by executive dysfunctions. The complete biochemistry of these dysfunctions remain misunderstood. Most studies have focused on the well-known nigro-striatal dopaminergic degenerations of PD, but a more satisfying understanding of the SCFS has come from the study of the cholinergic systems. We present here two new experiments carried out with long-term and acute anticholinergic treatments in PD. In the first experiment, the effects of a 2-week treatment with trihexyphenidyl were compared to those observed under placebo on a neuropsychological battery. Results showed that anticholinergic-induced deficits in PD were exclusively concerned with executive functions. In the second experiment, the effects of an acute subclinical dose of scopolamine were compared between normal controls and PD patients who were devoid of cognitive deficit on a subset of executive tasks. Results indicates that PD patients but not normal controls developed a transient SCFS for the duration of the drug action. In contrast to other populations with cholinergic depletions-such as Alzheimer's disease-cholinergic blockade in PD exacerbates specifically the SCFS. Such a discrepancy between these two neuropsychological profiles are discussed in terms of the specificity of the underlying cholinergic lesions.

Neuroleptic malignant syndrome associated with abrupt withdrawal of anticholinergic agents

Neuroleptic malignant syndrome (NMS) is a severe side-effect of neuroleptic treatment. It is usually related to hypodopaminergic activity. A young schizophrenic patient who developed a typical episode of NMS during abrupt withdrawal of long-acting neuroleptic combined with anticholinergic treatment is described. NMS appeared following combined neuroleptic/ anticholinergic withdrawal and responded to procyclidine administration. The appearance of NMS after discontinuation of antidopaminergic treatment seems to be in conflict with the hypodopaminergic theory of this adverse effect. It is suggested that simultaneous withdrawal of both anticholinergic and neuroleptic medications, mainly long-acting neuroleptics, seems to be a risk factor for NMS.

Psychotoxic effects of benzhexol hydrochloride (Artane)

Benzhexol hydrochloride (Artane, Pipanol, Trihexyphenidyl) was the first of a range of synthetic antispasmodic drugs to be made available for the symptomatic treatment of Parkinsonism. Selected as the most potent of a series of substituted piperidyl propanols examined pharmacologically by Cunningham et al. (1949), it was shown to have half the activity of atropine sulphate in inhibiting neurogenic spasm in isolated rabbit intestine. This activity was associated with advantageously reduced mydriatic, anti-sialogogic and vagal inhibitory properties in laboratory animals.

Disturbance of recent memory function in parkinsonian patients on anticholinergic therapy

Disruption of cholinergic neurotransmission may result in memory impairment. In this study the anticholinergic drug, trihexyphenidyl, at low doses when administered chronically for one month to Parkinson disease patients caused a decrease in performance on recent but not immediate memory tests. Awareness of possible deterioration of memory function of parkinsonian patients on anticholinergic medication is necessary.

Comparative trial of benzhexol, amantadine, and levodopa in the treatment of Parkinson's disease

Fourteen slightly disabled patients with Parkinsonism were treated separately with benzhexol, amantadine, and levodopa. Benzhexol and amantadine both gave a 15% reduction in functional disability and levodopa a 36% reduction. Benzhexol lessened the rigidity and improved the flexion of posture of Parkinson's disease, but had little or no effect on akinesia and tremor. Amantadine and levodopa caused improvement in all these symptoms. The combination of benzhexol and amantadine was as effective after four weeks of treatment as levodopa was after six months.

Increased anticholinergic challenge-induced memory impairment associated with the APOE-epsilon4 allele in the elderly: a controlled pilot study

The degree to which elderly adults experience cognitive impairments from centrally acting anticholinergic drugs is variable, but the cause of this variability is unknown. The present study examined the epsilon4 allele as a possible modulator of the effects of trihexyphenidyl hydrochloride (Artane( trade mark )), an anticholinergic drug, on memory functioning. Of the 24 cognitively intact, elderly participants (age range 62-76), 12 who possessed the epsilon4 allele, participated in a double-blind, randomized, placebo-controlled, crossover, three-way study. All participants were tested after receiving a single oral dose of trihexyphenidyl (1 or 2 mg) or placebo, with a 7-day washout period between sessions. Memory and psychomotor tests were administered at baseline, and at 1, 2.5, and 5 h post-treatment. Results showed that participants with the epsilon4 allele demonstrated significant impairments in delayed recall after both 1 and 2 mg doses of trihexyphenidyl while the non-epsilon4 group did not. Additionally, while acute administration of the 2 mg dose significantly impaired total recall in both epsilon4 and non-epsilon4 carriers, the epsilon4 carriers showed a more persistent impairment. These findings held when participants with the epsilon2 allele were excluded from the analyses. The epsilon4 groups did not differ with respect to psychomotor performance or plasma drug levels. These results provide evidence suggesting that the epsilon4 allele plays a significant role in increasing cognitive sensitivity to trihexyphenidyl and that a temporal component of memory consolidation may be especially vulnerable. A larger study is warranted to confirm these preliminary findings.

Recurrent heat-related illnesses during antipsychotic treatment

OBJECTIVE

To report a case of recurrent heat-related illnesses associated with the use of benzhexol, chlorpromazine, and zuclopenthixol decanoate.

CASE SUMMARY

During the summer of 2004, a 48-year-old man with a history of diabetes mellitus and schizophrenia was twice admitted to the hospital because of heat-related illnesses. On both occasions, he had been working under the sun in an open car park. His medications included benzhexol 2 mg twice daily, chlorpromazine 650 mg at bedtime, and zuclopenthixol decanoate intramuscular injection 600 mg every 4 weeks. In the first admission, the clinical diagnosis was heat stroke. He was discharged home on day 14, with precautionary advice against heat stroke. In the second admission, the clinical diagnosis was heat exhaustion. He was discharged home on day 4 and reminded of the precautions against heat stroke. An objective causality assessment revealed that the adverse event was possibly drug related in the first admission and probably drug related in the second admission.

DISCUSSION

Several drugs can impair thermoregulation during exercise or under conditions of environmental heat stress. Anticholinergic drugs or drugs with anticholinergic effects can inhibit sweating and reduce heat elimination. Neuroleptics (antipsychotics), such as phenothiazines, have combined anticholinergic and central thermoregulatory effects. The set point of the temperature regulation center can be elevated by the antidopaminergic effect of antipsychotics, such as phenothiazines and thioxanthenes.

CONCLUSIONS

Certain drugs may induce or worsen heat-related illnesses. During a heat wave, special attention should be given to those most at risk, and the importance of preventive measures should be emphasized.

Adverse effects of anticholinergic antiparkinsonian drugs in tardive dyskinesia. An investigation of mechanism

10 long-term schizophrenic patients with tardive dyskinesia were studied over 14 weeks and maintained on their usual neuroleptic medications while anticholinergic antiparkinson drugs were employed and then discontinued, and the cycle then repeated. Discontinuation of anticholinergic medications resulted in improvement in dyskinetic movements and vice versa. Estimation of haloperidol equivalents in serum at four times suggested that changes in severity of tardive dyskinesia were not caused by changes in blood levels of neuroleptics. Levels of pituitary hormones were also estimated at four times. Prolactin levels tended to diminish in men over the course of the experiment. Growth hormone and thyrotropin values were mainly stable. However, the growth hormone levels peaked during the final 'off anticholinergic' condition and thyrotropin levels were consistently elevated.

Pharmacokinetics of trihexyphenidyl after short-term and long-term administration to dystonic patients

Although trihexyphenidyl has been used effectively for many years in the treatment of Parkinson's disease, little is known about its pharmacokinetics. Using a sensitive radioreceptor assay for anticholinergic drugs, we assayed trihexyphenidyl in human serum and studied its pharmacokinetics following short-term and long-term administration to patients with dystonia. Previously untreated patients had a biphasic semilogarithmic plot of serum concentration-time consisting of an initial rapid distribution phase and a later slower elimination phase. Patients on long-term treatment showed only the slower elimination phase. Elimination followed first-order kinetics and was rapid, with a half-life of 3.7 +/- 0.4 (SEM) hours. There was no relationship between half-life and peak serum level, age, duration of therapy, or etiology or severity of dystonia. Although acute anticholinergic side effects paralleled the rise and fall of serum anticholinergic levels, the response of dystonia did not.

Treatment of neuroleptic malignant syndrome with subcutaneous apomorphine monotherapy

A 20-year-old psychiatric patient receiving haloperidol treatment developed acute-onset fever, rigidity, and mental changes. Subcutaneous apomorphine was given alone for treatment. The patient had rapid clinical improvement after the treatment. Serial blood examinations showed decline and subsequent normalization of the creatine phosphokinase levels.

Anticholinergic-induced chorea in the treatment of focal dystonia

The occurrence of chorea, induced by trihexyphenidyl (benzhexol hydrochloride) during the treatment of five adult patients who had focal or segmental dystonia, is described. The dose at which chorea appeared ranged from 15 to 60 mg/day (mean 31.7 mg/day). All but one patient had developed common adverse effects of this drug (dry mouth, blurred vision, and confusion) at lower doses (mean 21.8 mg per day). There was an inverse relationship between the age of the patient and the dose of trihexyphenidyl at which chorea developed.