Complete resolution of clozapine-induced sialorrhea with low dose trihexyphenidyl

Clozapine-induced sialorrhea (CIS) is a frequently occurring debilitating adverse effect. Although various treatment options exist, none has been proved to be distinctly superior to others. We report a case of CIS that responded to low dose of trihexyphenidyl (2 mg/day).

Interactions between neurons in the frontal cortex and hippocampus in cats trained to select reinforcements of different value in conditions of cholinergic deficiency

An operant food-related conditioned reflex was developed in six cats by the "active choice" protocol: short-latency pedal presses were followed by presentation of low-quality reinforcement (bread-meat mix), while long-latency pedal presses were followed by presentation of high-quality reinforcement (meat). Animals differed in terms of their food-procuring strategies, displaying "self-control," "ambivalence," or "impulsivity." Multineuron activity was recorded from the frontal cortex and hippocampus (field CA3). Cross-correlation analysis of interneuronal interactions within (local networks) and between (distributed networks) study structures showed that the numbers of interneuronal interactions in both local and distributed networks were maximal in animals with "self-control." On the background of systemic administration of the muscarinic cholinoreceptor blockers scopolamine and trihexyphenidyl, the numbers of interneuronal interactions decreased, while "common source" influences increased. This correlated with impairment of the reproduction of the selected strategy, primarily affecting the animals' self-controlled behavior. These results show that the "self-control" strategy is determined by the organization of local and distributed networks in the frontal cortex and hippocampus.

Sustained improvement of motor function in hemiparkinsonian rats chronically treated with low doses of caffeine or trihexyphenidyl

The effects of chronic oral treatment with low doses of caffeine (1-3 mg/kg) and trihexyphenidyl (0.1-0.2 mg/kg) were tested on hemiparkinsonian rats, which received the following treatments in a counterbalanced order: vehicle, caffeine, trihexyphenidyl, and caffeine plus trihexyphenidyl. Three preclinical models were used: the stepping test, the cylinder test, and the staircase test. Compared to pre-lesion values, the forepaw contralateral to the dopamine-denervated side showed impaired stepping, fewer wall contacts in the cylinder test, and fewer pellets retrieved in the staircase test. In the stepping test both doses of caffeine produced a complete recovery of motor function (100%), whereas the effect of trihexyphenidyl was less intense (77-80%). In this same test the maximal effect of drugs did not develop tolerance during 2-3 weeks, and was completely reversible after drug cessation. In the cylinder test only the wall contacts performed simultaneously with both forepaws were significantly increased by caffeine (3 mg/kg) and trihexyphenidyl (0.2 mg/kg), and this effect was also reversible. In the staircase test none of the treatments improved food pellet retrieval with the contralateral forepaw. Altogether, these results show that chronic treatment with caffeine, at doses similar to daily human consumption, produces a sustained improvement in the use of the contralateral forelimb in unilaterally 6-hydroxydopamine denervated rats, without the development of tolerance. Although the combined administration of caffeine plus trihexyphenidyl showed no synergism in these models, the results suggest that low doses of caffeine (1-3 mg/kg/day) could be of therapeutic value for the reversal of motor symptoms in parkinsonian patients.

[Interrelations between neurons of the frontal cortex and hippocampus under cholinergic deficit in choice behavior of cats]

Appetitive instrumental conditioned reflexes on light (CS+) were formed in six cats by the method of "active choice" of quality of reinforcement; bread-meat mixture was given after short-delay conditioned bar-press responses, and the delayed responses were rewarded by meat. The animals differed in choice behavior strategy: "self-control", "ambivalent", "impulsive". The multiunit activity in the frontal cortex and hippocampus (CA3) was recorded. Cross-correlation analysis was used for estimation of correlation of activities in neuronal pairs in the frontal cortex and hippocampus (distributed frontal-hippocampal networks) and pairs within the same structure (frontal and hippocampal local neuronal networks). It was shown that the number of cross-correlations between the discharges of neurons both in the local and distributed networks was significantly higher in "self-control" cats. Under conditions of systemic administration of antagonists of muscarinic central cholinoreceptors (trihexyphenidyl and scopolamine), the bar-press conditioning impaired, the number of direct interneuronal connections decreased, and the number of externally synchronized correlations ("common input") significantly increased. The results suggest that the local and distributed neural networks of the frontal cortex and hippocampus are involved in the system of brain structures that determine the behavioral strategy of "self control".

Trihexyphenidyl (Artane): a Brazilian study of its abuse

In Brazil, the medicinal misuse of trihexyphenidyl (Artane) has been observed among several segments of society. The present study was conducted in the city of São Paulo during 2002 to characterize this abuse. A sample of 21 users and 16 ex-users was interviewed using qualitative methodology; the subjects were single, unemployed, male polydrug users, who used trihexyphenidyl in order to attain states of mental alterations, mainly hallucinations and deliriums. Trihexyphenidyl is consumed in association with alcohol, other licit drugs (benzodiazepines), or illicit drugs, impairing cognitive functions such as memory, attention, and learning, intervening with some activities of users' daily life.

Assessment of the therapeutic and anticonvulsive efficacy of a drug combination consisting of trihexyphenidyle and HI-6 in soman-poisoned rats

1. The influence of two anticholinergic drugs (atropine, trihexyphenidyle) on the effectiveness of antidotal treatment to eliminate soman-induced lethal effects and convulsions was studied in rats. 2. The oxime HI-6 when combined with centrally acting anticholinergic drug trihexyphenidyle seems to be more efficacious in the elimination of acute toxic effects of soman than its combination with atropine. 3. The findings support the hypothesis that the choice of the anticholinergic drug is important for the effectiveness of antidotal mixture in the case of antidotal treatment of soman-induced acute poisoning.

Effect of methoxime combined with anticholinergic, anticonvulsant or anti-HCN drugs in tabun-poisoned mice

The effect of methoxime combined with a) atropine, b) benactyzine, c) atropine and natrium thiosulphate, d) atropine and diazepam on antidotal treatment effectiveness was studied in tabun-poisoned mice. In addition, the influence of pretreatment consisiting of pyridostigmine, benactyzine and trihexyphenidyle (PANPAL) administered 2 hours before tabun intoxication on the treatment effectivity of methoxime combined with e) atropine or f) benactyzine was tested. The most efficacious therapeutic mixture in non-pretreated mice was methoxime, atropine and diazepam. Natrium thiosulphate did not significantly increase neither decrease the antidotal treatment efficacy in comparison with methoxime and atropine alone. Pretreatment with PANPAL significantly decreased tabun toxicity (nearly 4 times in methoxime and benactyzine combination and more than 4 times in atropine and methoxime mixture). The present study demonstrates that the tabun toxicity in mice is more effectively reduced when PANPAL prophylactically is administered than in case of treatment with methoxime and cholinergic drug alone. We established that anticholinergic drug option in the therapeutic mixture of methoxime and anticholinergic drug did not cause the difference in the antidotal treatment effectivities.

A comparison of the neuroprotective efficacy of pharmacological pretreatment and antidotal treatment in soman-poisoned rats

1. To study the influence of pharmacological pretreatment (PANPAL or pyridostigmine combined with biperiden) and antidotal treatment (the oxime HI-6 plus atropine) on soman-induced neurotoxicity, male albino rats were poisoned with a lethal dose of soman (54 (g/kg i.m.; 100% of LD50 value) and observed at 24 hours and 7 days following soman challenge. The neurotoxicity of soman was evaluated using a Functional observational battery and an automatic measurement of motor activity. 2. Pharmacological pretreatment as well as antidotal treatment were able to eliminate some of soman-induced neurotoxic effects observed at 24 hours following soman poisoning. The combination of pharmacological pretreatment (PANPAL or pyridostigmine combined with biperiden) and antidotal treatment was found to be more effective in the elimination of soman-induced neurotoxicity in rats at 24 hours following soman challenge in comparison with the administration of pharmacological pretreatment or antidotal treatment alone. To compare both pharmacological pretreatments, the combination of pyridostigmine with biperiden seems to be more efficacious to eliminate soman-induced signs of neurotoxicity than PANPAL. 3. At 7 days following soman poisoning, the combination of pharmacological pretreatment involving pyridostigmine and biperiden with antidotal treatment was only able to completely eliminate soman-induced neurotoxic signs. 4. Thus, our findings confirm that the combination of pharmacological pretreatment and antidotal treatment is able not only to protect the experimental animals from the lethal effects of soman but also to eliminate most soman-induced signs of neurotoxicity in poisoned rats. The pharmacological pretreatment containing pyridostigmine and biperiden appears to be more efficacious to eliminate soman-induced neurotoxic sings than PANPAL.

Anticholinergic drugs: response of parkinsonism not responsive to levodopa

A 41 year old man with parkinsonism and pyramidal signs is described. He was non-responsive to levodopa and dopamine receptor agonists but dramatically responded to trihexyphenidyl. In this patient, brain MRI showed bilateral hyperintensities along the corticospinal tracts on T2 weighted images. PET studies showed a decrease in (18)F-6-fluorodopa uptake in the putamen contralateral to the more affected limbs and normal D(2) receptor binding in the putamen. The PET and MRI findings and responsiveness to antiparkinsonian agents suggested degeneration of nigrostriatal dopaminergic neurons, striatal output pathways, and corticospinal tracts.

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.

Carriers for skin delivery of trihexyphenidyl HCl: ethosomes vs. liposomes

The purpose of this work was to characterize a novel ethosomal carrier containing trihexyphenidyl HCl (THP) and to investigate the delivery of THP from ethosomes versus classic liposomes. THP-ethosomal systems were shown by electron microscopy to contain small, phospholipid vesicles. As the THP concentration was increased from 0 to 3%, the size of the vesicles decreased from 154 to 90 nm. This is most likely due to the surface activity of THP (critical micelle concentration of 5.9 mg/ml), as measured in this work. In addition, the ethosome zeta potential value increased as a function of THP concentration, from -4.5 to +10.4 when the THP concentration was increased from 0 to 3%. In contrast, THP liposomes were much larger and their charge was not affected by THP. When compared with standard liposomes, ethosomes had a higher entrapment capacity and a greater ability to deliver entrapped fluorescent probe to the deeper layers of skin. The flux of THP through nude mouse skin from THP ethosomes (0.21 mg/cm2 h) was 87, 51 and 4.5 times higher than from liposomes, phosphate buffer and hydroethanolic solution, respectively (p < 0.01). The quantity of THP remaining in the skin at the end of the 18-h experiment was statistically significantly greater from the ethosomal system than from liposomes or a control hydroethanolic solution. Our results indicate that the ethosomal THP system may be a promising candidate for transdermal delivery of THP.

[A case of amoxapine-induced tardive dystonia successfully treated with a low dose anti-cholinergic agent]

We report a 63-year-old man who presented with amoxapine-induced tardive dystonia. At 49 years of age, he developed depression and was administrated 50 mg amoxapine, 4 mg cloxazoram and 3 mg biperiden per day. The daily dose of amoxapine was gradually increased up to 150 mg at 58 years of age. At 61 years of age and after having been taking amoxapine for twelve years, he noticed a rotating left arm and muscle pain in his left shoulder and arm while walking. At 62 years of age, he stopped taking these three drugs. However, the dystonic movements and pain both continued to get worse. Neurological findings revealed no abnormality except for a dystonic posture and movements in the neck and bilateral arms while sitting, standing and walking. Positron emission tomography with C-11 raclopride revealed a mild decrease in the dopamine D 2 receptor numbers in the bilateral striatum. However, two dopamine agonists, pergolide and bromocriptine, worsened his dystonia. In contrast, the daily administration of 2 mg of trihexyphenidyl, an anti-cholinergic agent, markedly ameliorated the dystonia symptoms. As a result, the long-term co-administration of biperiden, an anti-cholinergic agent, may mask the toxicity of amoxapine, which may induce tardive dystonia.

Childhood head tremor

We report here four children (three girls, one boy) with head tremor followed longitudinally, ages 15 months to 11 years, with follow-up over 1 to 8 years. Each demonstrated onset of head tremor between the ages of 5 and 10 months. In each case head tremor was characterized by a predominant "yes-yes" or "no-no" movement of the head. In two of the children the movement was slightly skewed with chin movement toward the shoulder. Oscillations were at a frequency of about 1 to 2 Hz. They were accentuated when sitting upright without head support, increased at times of movement, and dissipated while lying flat or sleeping. The children were unable to voluntarily suppress the action and did not experience any sensation of movement. Three of the children had shuddering spells prior to onset of head tremor. Two children have developed mild dystonic posturing of the legs when intently concentrating. Their general and neurologic examinations were normal. Normal investigations included brain magnetic resonance imaging and computed tomography, urine amino acids and organic acids screening, serum lactate, erythrocyte sedimentation rate, antinuclear antibodies, and ceruloplasmin and copper levels. A family history of tremor was present in two children, maternal epilepsy in one child, and infantile shuddering occurred in the father of one child. Therapy included trials of selective and nonselective beta-adrenergic blockers, alpha-adrenergic agonists, anticholinergics, anticonvulsants, and amantadine. One child responded well to both timolol and trihexyphenidyl. A second child responded moderately to primidone. Two have not been treated. Two have had head tremor spontaneously remit. We conclude from this small series of children with head tremor that it can evolve from a prior history of shuddering spells, occurs in the context of a positive family history of tremor, and can be accompanied by the development of a mild dystonia. Therapeutic response is variable to multiple agents. Spontaneous remission occurs, suggesting a benign course.

Treatment of Meige's syndrome with ECT

A 62-year-old woman with Meige's syndrome failed to respond to several pharmacologic interventions. Her dystonias improved significantly after treatment with bilateral electroconvulsive therapy (ECT). However, the effect was not durable, lasting < or = 72 h. ECT is an effective treatment for many movement disorders including dystonias of differing etiologies. Its efficacy for Meige's syndrome is questionable.

Trihexyphenidyl in posthemorrhagic dystonia: motor and language effects

Trihexyphenidyl has been found to be an effective treatment for dystonic movement disorders, improving gross motor function in patients with axial and torsional dystonia, tremors, and myoclonus. In this report, improvements in fine motor control, language, and oral motor skills are described with trihexyphenidyl in an 8-year-old female who developed dystonia after spontaneous bilateral putamenal hemorrhages. No adverse side effects occurred. The mechanism of action of trihexyphenidyl is believed to be in the basal ganglia where it inhibits muscarinic cholinergic receptors and increases the turnover of dopamine.

Influence of ammonium chloride on the tissue distribution of anticholinergic drugs in rats

Ammonium chloride (NH4Cl) increases lysosomal pH and thereby abolishes intralysosomal accumulation of drugs. Its effect on the tissue distribution of biperiden and trihexyphenidyl in rats has been investigated. The tissue-plasma concentration ratios (Kp) of these drugs in various tissues were determined by infusion studies at steady-state in the presence or absence of NH4Cl. Treatment with NH4Cl reduced the Kp values for both drugs, causing the largest reduction in Kp in the lung (52.1 to 11.8 for biperiden and 59.5 to 18.9 for trihexyphenidyl; ratios of decrease 0.77 and 0.68, respectively), followed by the heart and kidneys, with relatively small reductions in the brain, gut, muscle and fat. Subcellular fractionation studies in the lung indicated that the subcellular fraction-plasma concentration ratio of each drug at the steady state (K(p,sf)) was reduced by treatment with NH4Cl, with the largest decrease in the post-nuclear fraction (ratio of decrease 0.82 for biperiden and 0.74 for trihexyphenidyl), followed by the nucleus, microsomes and supernatant, in that order. A strong correlation was found between the ratio of decrease in K(p,sf) after NH4Cl treatment and the specific activity of acid phosphatases, a marker of lysosomes, in each fraction (biperiden, r = 0.948; trihexyphenidyl, r = 0.945). These results suggest that acidic organelles contribute significantly to the distribution kinetics of anticholinergic drugs.

[The effect of pharmacologic prophylaxis with Panpal on acetylcholinesterase activity in the diaphragm and various parts of the brain in rats during treated and untreated Soman poisoning]

BACKGROUND

The pharmacological prophylaxis protecting the organism against organophosphorus compounds could increase the effect of antidotal treatment of poisoning with organophosphates.

METHODS AND RESULTS

The influence of the pharmacological prophylaxis with Panpal (pyridostigmine in combination with benaetyzine and trihexyphenidyle) on acetylcholinesterase activity in diaphragm and various parts of brain at 1 and 3 h following non-treated and treated (the oxime HI-6 in combination with atropine) soman poisoning was tested on male rats. While Panpal did not significantly influence the acetylcholinesterase activity in brain following non-treated as well as treated soman poisoning. Panpal increased so many-induced acetylcholinesterase inhibition following non-treated poisoning and decreased the reactivating effect of the oxime HI-6 following treated soman poisoning in diaphragm.

CONCLUSIONS

Our data confirm the importance of the combination of reversible acetylcholinesterase inhibitor pyridostigmine with anticholinergic drugs in the pharmacological prophylaxis of soman poisoning because of the elimination of consequences of pyridostigmine-induced increasing in acetylcholinesterase inhibition in the peripheral compartment.

Effect of Panpal pretreatment and antidotal treatment (HI-6 plus benactyzine) on respiratory and circulatory function in soman-poisoned rats

1 The effect of pharmacological pretreatment (pyridostigmine, benactyzine and trihexyphenidyle), designated Panpal, and antidotal treatment (the oxime HI-6 plus benactyzine) in soman poisoning was investigated in a rat model with on-line monitoring of respiratory and circulatory parameters. 2 Soman poisoning caused a high decrease in respiratory rate as well as minute respiratory volume and an increase in mean arterial pressure from 30-120 min following soman challenge. Soman at sublethal dose also significantly inhibited acetylcholinesterase activity in diaphragm and various brain parts. 3 Panpal pretreatment as well as antidotal treatment were effective in improving the respiratory and circulatory function disturbed by soman without the ability to increase significantly soman-inhibited acetylcholinesterase activity in all brain parts studied. 4 The efficacy of combined Panpal pretreatment and antidotal treatment against sublethal soman poisoning was not different from the efficacy of Panpal pretreatment or antidotal treatment alone. 5 The results of this investigation suggest that Panpal pretreatment as well as antidotal treatment are able to restore respiratory and circulatory function in soman-poisoned rats without significant reactivation of brain acetylcholinesterase.

Postencephalitic stereotyped involuntary movements responsive to L-Dopa

In 1954, at the age of 5 years, our patient had an encephalitic syndrome associated with a prolonged lethargic state. After this episode, he developed a severe parkinsonian syndrome that, after a few years, was associated with axial dystonia and stereotyped abnormal movements of the upper limbs. This complex and progressive extrapyramidal syndrome had many similarities to the encephalitis lethargica as described by von Economo. Results of cerebral computed tomography and magnetic resonance imaging were normal. Fluorodopa positron emission tomography showed a significant bilateral reduction of tracer accumulation in both putamen, similar to that observed in patients with idiopathic Parkinson's disease. However, in this patient, treatment with L-Dopa suppressed all akinetic, dystonic and dyskinetic symptoms. The effectiveness of L-Dopa was abolished by administration of a D2 antagonist and was fully reproduced by a D2 agonist. In conclusion, this patient presented a complex postencephalitic, extrapyramidal syndrome, with akinetic symptoms and involuntary movements. These symptoms appeared to be related to a limited lesion of the dopaminergic neurons of the zona compacta of the substantia nigra.

The influence of pharmacological pretreatment on efficacy of HI-6 oxime in combination with benactyzine in soman poisoning in rats

1. The influence of pharmacological pretreatment (pyridostigmine, benactyzine and trihexyphenidyle), designated PANPAL, on soman-induced cholinergic and stressogenic effects as well as on the efficacy of antidotal treatment (HI-6 plus obidoxime) in rats was studied. 2. PANPAL prophylaxis significantly decreased soman-induced cholinesterase inhibition in blood, brain and diaphragm as well as stressogenic effects of soman (an increase in plasma corticosterone level and liver tyrosine aminotransferase activity). 3. PANPAL pretreatment did not improve the efficacy of HI-6 in combination with benactyzine on soman-induced anticholinesterase and stressogenic effects. 4. These findings confirm that PANPAL prophylaxis can improve prognosis of soman poisoning especially by protection of cholinesterases.

Involvement of respiratory muscles in adult-onset dystonia: a clinical and electrophysiological study

Involvement of respiratory muscles is unusual in dystonia, but its occurrence may be underestimated either because it is not conspicuous or because it is improperly imputed to another cause. Three patients who had adult-onset dystonia and who were exhibiting respiratory problems were examined clinically and electrophysiologically. In the three patients the onset was focal-cervical in two and blepharospasm in one. The respiratory problems appeared later. The first patient had involuntary deep and loud inspirations combined with spasms of axial dystonia, the second complained of breathing arrests, and the third had deep inspirations mainly on speaking or reading aloud, thus causing broken speech. Electromyographic findings, including of the diaphragm, were quite consistent with a respiratory involvement in these three cases of dystonia. Assuming that respiratory troubles could be in the first sign of a focal dystonia, electrophysiological studies of respiratory muscles could be used to confirm this.

[Antiparkinson drugs in neuroleptic treatment: comparative study of progressive and abrupt withdrawal]

The systematic and long term association of anti-parkinsonian drugs to neuroleptics is questioned by many authors because of their side effects and their toxicomanogenous risks whereas their efficiency in extrapyramidal effects of prophylaxis is not certain. This work aims at evaluating the interest of prescribing long term parkinsonian drug in association with neuroleptics. The study centered on 101 psychotic patients treated with neuroleptics, and followed on an ambulatory bases. 97% of this patients systematically received antiparkinsonian drugs. Extrapyramidal symptoms of varied intensity have noted for 61% of patients. The authors have compared, in double blind, the effects of the progressive and abrupt withdrawal of anti-parkinsonian drugs for 37 patients among the 101. These patients have been regularly treated for at least 6 months by neuroleptics (fluphenazine or pipothiazine) in association with trihexyphenidyle. They were randomly divided into 3 groups, and statified by sex and type of neuroleptic. For group I, composed of 13 patients, trihexyphenidyle is abruptly withdrawn and replaced by a placebo. For group II, composed of 11 patients, withdrawal is progressive for 2 weeks, trihexyphenidyle being replaced by a placebo. Group III, composed of 13 patients, is a sample group which went on receiving trihexyphenidyle. The results of this study showed that within the brutal withdrawal group (group I), 10 patients over 13 needed trihexyphenidyle again, whereas only 3 patients over 11 needed it in the progressive withdrawal group (group II). In the sample group (group III), one patient over 13 showed extrapyramidal symptoms, necessitating his leaving school. The global chi 2 is significant with p < 0.001.(ABSTRACT TRUNCATED AT 250 WORDS)

"Apraxia of lid opening," a focal eyelid dystonia: clinical study of 32 patients

We have seen 32 patients with "apraxia of lid opening" (ALO) in the following clinical settings: as an isolated condition (3 patients), idiopathic blepharospasm (BSP, 20 patients, including 4 familial cases), progressive supranuclear palsy (PSP, 7 patients), and dystonic parkinsonian syndrome (2 patients). Twenty-nine patients treated with botulinum toxin into the orbicularis oculi muscle were rated before and after treatment and 83% of the patients improved on a clinical scale. Best results were obtained with injections directed toward the junction of the preseptal and pretarsal parts of the palpebral orbicularis oculi. Several patients also improved on anticholinergic drugs. Besides medical treatment, lid crutches, in conjunction with botulinum toxin injections, were useful in some patients. ALO is not a true apraxia; it constitutes an eyelid dystonia as shown by its clinical and electrophysiological features as well as pharmacological reactions and is encountered in a clinical spectrum ranging from an isolated form to predominant BSP. It was an important cause of treatment failures in botulinum toxin-treated BSP but by modifying our injection strategy and by adding anticholinergic drugs and also lid crutches, we obtained a good functional benefit.

Focal dystonia and speech impairment responding to anticholinergic therapy

Focal dystonia of the right hand and speech impairment as a result of a circumscribed left-sided anterior thalamic lesion is reported in a 9-year-old girl with borderline normal psychomotor development. Both focal dystonia and speech impairment improved during anticholinergic treatment and worsened after drug withdrawal.

A component analysis of the generation and release of isometric force in Parkinson's disease

Paradigms of isometric force control allow study of the generation and release of movement in the absence of complications due to disordered visuomotor coordination. The onset and release of isometric force in Parkinson's disease (PD) was studied, using computerised determinants of latency of response and rate of force generation and release. Components of isometric force control were related to measures of cognitive, affective and clinical motor disability. The effects of treatment were determined by longitudinal study of de novo patients. Patients with PD showed impairment in latency and rate of force change for movement release as well as onset. Rate of force change correlated with depression, clinical motor disability and memory quotient but latency showed no correlation with any of these measures. Treatment improved rate of force release, in concert with clinical motor disability, but not latency. These results suggest dissociations between latency and rate of force change that may be linked to different neurochemical deficits. Further, they demonstrate akinetic deficits in force release that argue against the "neural energy hypothesis" of akinesia.

Myoclonic dystonia

Myoclonic dystonia is a rare disorder that occurs in an hereditary and a sporadic form. The autosomal-dominantly inherited form is responsive to alcohol but not to other drugs. The sporadic form has been relatively resistant to drug treatment. We report a young man with myoclonic dystonia who displayed only little response to alcohol but improved significantly with a combination of sodium valproate for myoclonus and trihexiphenidyl hydrochloride for dystonia. His rehabilitation, however, was confounded by public authorities who thought the patient's appearance was indicative of drug use.

Effects of trihexyphenidyl on plasma chlorpromazine in young schizophrenics

This study investigated the effects of trihexyphenidyl on chlorpromazine (CPZ) plasma levels and clinical state in 20 relatively young schizophrenic patients diagnosed using the DSM-III. Spontaneous changes in CPZ plasma levels over time were also examined. Trihexyphenidyl significantly increased CPZ plasma levels (average 41%) but did not produce clinical change. The trihexphenidyl-induced increase in CPZ plasma levels was independent of CPZ oral dosage and of CPZ plasma levels. Chlorpromazine plasma levels decreased non significantly (about 13%) over the four weeks following steady state, but there was marked inter-subject variability, and CPZ levels rose in some subjects. Although identical CPZ doses produced widely variable plasma levels, CPZ plasma levels correlated significantly with oral dose. The views that antiparkinsonian drugs interfere with neuroleptic efficacy, and do so by lowering neuroleptic plasma levels, are questioned.

[Parkinson syndrome after administration of acetylcholine into the caudate nuclei]

Rats with the Parkinsonian syndrome induced by administration of acetyl choline and proserine into the rostral part of both caudate nuclei manifest an increased electrical activity (EA) in this part. Tremor, oligokinesia and rigidity are characterized by the appearance of paroxysmal EA with high amplitude of slow and rapid waves. The data obtained allow to conclude that neuropathophysiological basis of the Parkinsonian syndrome is the formation of the generator of pathologically enhanced excitation (GPEE) in the caudate nuclei. Some peculiarities of the GPEE activity in tremor and akinetic rigidity syndromes were observed. Intrarostral administration of dopamine or intraperitoneal administration of cyclodol resulted in the inhibition of GPEE and disappearance of clinical manifestations of Parkinsonian syndrome.

Pharmacokinetic evaluation of a sustained-release formulation of trihexyphenidyl in healthy volunteers

Twenty-four male subjects were randomized to receive two oral dosage forms of trihexyphenidyl HCl (alpha-cyclohexyl-alpha-phenyl-1-piperidinepropanol HCl). The dosage regimens were (1) a 5-mg immediate release (IR) tablet given twice daily at time zero and 12 h later, and (2) two 5-mg sustained-release (SR) capsule formulations given daily. The number of adverse experiences following the SR formulation were approximately 50% of those for the IR formulation, the peak concentration (Cmax) after the SR formulation was significantly lower (p less than 0.05) than that after the first dose of the IR formulation, and the time to reach Cmax (tmax) was significantly longer after the SR formulation (p less than 0.05). The SR formulation maintained serum concentrations above 50, 60, and 70% of Cmax values for average time periods of 11.7, 9.4, and 5.9 h, respectively, compared with values of 1.8, 1.2, and 0.9 h after the IR formulation; the differences were all significant (p less than 0.05). The mean elimination half-life (t1/2) was similar (p greater than 0.05) after the SR (10.1 h) and IR (8.7 h) formulations. The statistical power of the study was 98.1% to detect a 20% difference in the area under the curve from time zero to time infinity (AUC0----infinity) between formulations. Although the AUC0----infinity after the SR formulation was statistically smaller (p less than 0.05) than after the IR tablet, the difference was less than 20%. Therefore, the SR formulation was bioequivalent to the IR tablet formulation of trihexyphenidyl.

Effects of 4 weeks treatment with chlorpromazine and/or trihexyphenidyl on the pituitary-gonadal axis in male paranoid schizophrenics

Serum prolactin (PRL), luteinizing hormone (LH) and testosterone (T) levels were estimated in a group of 30 male paranoid schizophrenics before and after 4 weeks treatment with chlorpromazine and/or trihexyphenidyl, and in a group of 14 healthy male individuals. After treatment with chlorpromazine (100 mg t.i.d., p.o.), 10 patients presented a significant increase in serum PRL values and a significant decrease in serum T values. A significant increase in serum PRL values was also found in 10 patients who were treated with chlorpromazine (100 mg t.i.d., p.o.) plus trihexyphenidyl (5 mg t.i.d., p.o.). No significant difference in any of the investigated endocrine parameters was detected in 10 patients after 4 weeks administration of trihexyphenidyl (5 mg t.i.d., p.o.). Following chlorpromazine treatment with or without concomitant administration of trihexyphenidyl, 20 patients showed a significant increase in serum PRL levels and a significant decrease in serum LH and T levels.

Effects of chronic treatment with trihexyphenidyl and carbamazepine alone or in combination with haloperidol on substance P content in rat brain: a possible implication of substance P in affective disorders

To assess the roles of substance P in neurologic or psychiatric illnesses, effects of acute or chronic (40- or 80-day dietary) treatment with trihexyphenidyl and carbamazepine alone or in combination with haloperidol on substance P content were investigated in the rat brain. Either acute or chronic trihexyphenidyl administration did not alter substance P content when administered alone and did not prevent the haloperidol-induced substance P decrease in the striatum and substantia nigra when coadministered with haloperidol. Chronic dietary carbamazepine administration dose-dependently increased substance P content in the striatum and substantia nigra, but not in the raphe area, in a haloperidol-reversible manner. Carbamazepine also dose-dependently increased gamma-aminobutyric acid levels in the substantia nigra without altering the striatal dopamine turnover rate. The lack of effect of trihexyphenidyl, an anticholinergic drug used to treat antipsychotic drug-induced extrapyramidal (Parkinson) syndromes, suggests that antipsychotic drug-induced reduction in substance P content is not involved in the extrapyramidal side effects. Since the effects of carbamazepine on substance P content are identical with previously described effects of lithium, an alteration in substance P neurotransmission may be one of the neurochemical bases of common clinical and behavioral effects of carbamazepine and lithium on affective disorders.

[Akinetic mutism from recurrent hydrocephalus: successful treatment with levodopa, bromocriptine and trihexyphenidyl]

A case of akinetic mutism was reported with reference to a marked improvement by levodopa, bromocriptine and trihexyphenidyl. A 39-year-old male, first seen on February 2, 1981, had an occipitalgia, accompanied by nausea and vomiting. For several months before this consultation, the patient had suffered from asthenopia. Brain CT scan and cerebral angiogram demonstrated internal hydrocephalus due to aqueduct stenosis of unknown etiology. After a ventriculoperitoneal shunt operation on February 20, 1981, he completely recovered. Two years and a half after the shunt insertion he had no difficulty in his daily life. He reentered the hospital on December 21, 1983, because of personality change, mental deterioration and bradykinesia. Brain CT scan showed recurrent hydrocephalus resulting from shunt blockage. Following the shunt revision, hydrocephalus was resolved. Nevertheless, the patient did not return to his previous state. And he became bed-ridden, incontinent of urine, and unable to take fluids or foods, following which he went into a state of akinetic mutism. Other neurological findings were as follows: upward gaze palsy, impaired convergence, convergence nystagmus, plastic rigidity of neck and all four limbs, and diffuse hyperreflexia with right Babinski's sign. Abnormal involuntary movement was not seen. On March 27, 1984, levodopa therapy was instituted and on April 2, trihexyphenidyl was combined with levodopa. Shortly after administration of levodopa and trihexyphenidyl, akinetic mutism began to improve, but upward gaze palsy was not affected. He began to speak and could walk unassisted by the end of July.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

Pharmacological modification of DDT-induced tremor and hyperthermia in rats: distributional factors

Pretreatment of rats with hydantoin (75 mg/kg, PO, an anticonvulsant), trihexyphenidyl (10 mg/kg, SC, a muscarinic cholinergic antagonist), or piperonyl butoxide (500 mg/kg, PO, a metabolic inhibitor) had no effect on the whole blood or brain tissue levels of orally administered DDT (75 mg/kg) or its metabolites DDD and DDE. Hydantoin and piperonyl butoxide decreased DDT-induced tremor and hyperthermia due to DDT when measured 12 h after DDT exposure, while trihexyphenidyl augmented some components of DDT-induced tremor. Additional experiments found that pretreatment with piperonyl butoxide increased tremor due to permethrin exposure (120 mg/kg, PO), while having no effect on tremor due to chlordecone administration (60 mg/kg, IP). Pretreatment with ellipticine (30 mg/kg, IP, a metabolic inhibitor) also decreased tremor 12 h after DDT exposure. The effects of piperonyl butoxide and ellipticine on DDT-induced tremor are postulated to occur through direct actions of these compounds on nerve or muscle tissue. Hydantoin-induced attenuation of DDT-induced neurotoxicity may be due to the ability of hydantoin to block repetitive firing of nerves by binding to the inactivation gates of sodium.

The treatment of severe dystonia in children and adults

Twenty-three children (aged less than 18 years) and 17 adults with severe widespread dystonia were treated with high doses of benzhexol (up to 130 mg daily introduced slowly over many weeks). Children tolerated higher doses (median 30 mg/day) than adults (median 20 mg/day). 52% of the children gained useful benefit, many (43%) without unwanted side effects. Such an approach was less successful in adults; 41% gained benefit, but only 35% had no side effects. Twelve adults with severe axial dystonia, and two children with life-threatening generalised dystonia were treated with a combination of a low constant dose of tetrabenazine to which were added pimozide and benzhexol as necessary. The dose of tetrabenazine was aimed at 75 mg daily; pimozide was increased (6 to 25 mg/day) until the dystonia was relieved or Parkinsonism and other side-effects prevented further increments; if necessary benzhexol (6 to 30 mg/day) then was added to control side-effects and to provide additional benefit. 75% of the adults with severe axial dystonia, and one of the two children with life threatening generalised dystonia gained useful benefit from this regime. It is concluded that high dose benzhexol is the present first treatment of choice for children with severe dystonia, and is worth a try in adults but with less expectation of success. When benzhexol treatment alone fails in adults with severe disabling axial dystonia, or in children with life-threatening generalised dystonia, combined therapy with tetrabenazine, pimozide and benzhexol may give valuable symptomatic relief.

Mental impairment in Parkinson's disease. The role of anticholinergic drugs

The trial has been carried out on 33 treated Parkinsonian patients and 14 healthy controls. A series of psychometric tests were employed in order to show a possible intellectual deterioration in Parkinsonian patients. Bender's test showed greater motor-perceptive deterioration in Parkinsonian patients respect to control, the Wechsler-Bellevue Intelligence Scale evidenced in patients significant deterioration of mnesic and psychomotor capacity. When considering drug treatments patients undergoing combined treatment or anti-cholinergics alone obtained worse results in all tests made whilst patients on L-Dopa alone obtained the best results.