Randomized trials of dichlorphenamide in the periodic paralyses. Working Group on Periodic Paralysis. Improvement of muscle strength in familial hypokalaemic periodic paralysis with acetazolamide. Treatment with oral 3,4 diaminopyridine improves leg strength in multiple sclerosis patients: results of a randomized, double-blind, placebo-controlled, crossover trial. Quantitative assessment of sustained-release 4-aminopyridine for symptomatic treatment of multiple sclerosis. 3,4-Diaminopyridine in the treatment of Lambert-Eaton myasthenic syndrome. Ketazolam treatment for spasticity: double-blind study of a new drug. Efficacy and tolerability of acetazolamide in migraine prophylaxis: a randomised placebo-controlled trial. Double-blind, placebo-controlled, crossover trial of D-cycloserine adjuvant therapy for treatment-resistant schizophrenia. [Comparative double-blind study of the effectiveness and tolerance of baclofen, tetrazepam and tizanidine in spastic movement disorders of the lower extremities].
Although the carbonic anhydrase inhibitors have been used in the treatment of the primary periodic paralyses (PPs), their efficacy has not been demonstrated in double-blind, placebo-controlled trials. Therefore, we tested the efficacy of dichlorphenamide (DCP; Daranide), a potent carbonic anhydrase inhibitor, in the treatment of episodic weakness in the primary PPs. We performed two multicenter, randomized, double-blind, placebo-controlled crossover trials, one involving 42 subjects with hypokalemic periodic paralysis (HypoPP) and the other involving 31 subjects with potassium-sensitive periodic paralysis (PSPP). In each trial, two 8-week treatment periods were separated by an active washout period of at least 9 weeks. The primary outcome variable in the HypoPP trial was the occurrence of an intolerable increase in attack severity or frequency (end point). The primary outcome variable in the PSPP trial was the number of attacks per week. In the HypoPP trial, there were 13 subjects who exhibited a preference (in terms of the end point) for either DCP or placebo, and 11 of these preferred DCP. In the PSPP trial, DCP significantly reduced attack rates relative to placebo. DCP also significantly reduced attack rates relative to placebo in the HypoPP subjects. We conclude that DCP is effective in the prevention of episodic weakness in both HypoPP and PSPP. A double blind cross-over study of eight patients with familial hypokalaemic periodic paralysis was made to assess the influence of acetazolamide on muscle strength. All patients had a reduced interictal muscle fibre conduction velocity. Five patients had no attacks at the time of the study. One patient withdrew from the study because of an adverse reaction. The muscle strength of 11 muscle groups was measured with a hand-held dynamometer. The sum of force improved significantly in the seven patients (mean increase: 17%, p less than 0.05; 95% confidence interval: 7.2-26.8%). Endurance tests showed an improvement in the performance of 30 full kneebends. Surface EMG measurement showed no change in the muscle fibre conduction velocity or power spectra during treatment. The integrated EMG showed a (non significant) mean increase of 21%. To examine the efficacy and toxicity of oral 3,4 diaminopyridine (DAP) in dosages up to 100 mg/day, 36 patients with multiple sclerosis (MS) enrolled in a randomized, double-blind, placebo-controlled, crossover trial. The primary outcome measure was improvement of a prospectively defined neurologic deficit, which was leg weakness in 34 patients. Secondary outcome measures included the patient's subjective response, scored manual motor testing (MMT) of leg strength, scored leg strength from videotaped motor testing (VMT), quadriceps and hamstrings strength (QMT) measured by isometric dynamometry, neuropsychological testing (NPT), ambulation index (AI), and Expanded Disability Status Scale (EDSS) score. Paresthesias and abdominal pain were common and were dose limiting in eight patients. Three patients had episodes of confusion, and one patient had a seizure while on DAP. Eight patients withdrew from the study, leaving 28 evaluable patients for the efficacy analysis. The prospectively defined neurologic deficit improved in 24 patients-22 on DAP and 2 on placebo (p = 0.0005). All improvements were in leg weakness. Subjective response and measures of leg strength and function (MMT, VMT, QMT, and AI) improved on DAP compared with placebo. Neither NPT nor EDSS scores improved. DAP treatment can induce improvements in leg strength in MS patients, but toxicity is limiting in many patients. To evaluate the efficacy of 4-aminopyridine sustained release (4AP SR) (fampridine, EL-970) using quantitative measures of motor function in multiple sclerosis (MS) patients.
                In vitro, 4AP improves conduction through demyelinated axons. A previous multicenter trial of 4AP SR using the Expanded Disability Status Scale (EDSS) as the primary outcome was unable to establish clinical efficacy.
                Ten MS patients with stable motor deficits (EDSS 6.0-7.5) were given 4AP SR 17.5 mg bid and placebo for 1 week each in a double-blind, placebo-controlled, crossover trial. Time to walk 8 meters, time to climb four stairs, maximum voluntary isometric contraction measured quantitatively (MVICT), manual muscle testing (MMT), grip strength, EDSS, and the patient's global impression were measured.
                Timed gait was improved on 4AP SR compared with placebo in 9 of 10 subjects (p = 0.02). Timed stair climbing, MVICT, MMT, grip strength, and EDSS showed nonsignificant improvements on 4AP SR. Based on their global impressions, seven subjects preferred 4AP SR over placebo; only one preferred placebo. There were no serious side effects.
                4AP SR improved motor function in MS patients. The quantitative outcomes used in this study permit more sensitive evaluation of the therapeutic effect and promise to be useful in future trials of symptomatic treatments for MS. Lambert-Eaton myasthenic syndrome is characterized by muscle weakness, hyporeflexia, and autonomic dysfunction, which result from impaired release of acetylcholine from cholinergic nerve terminals. It is frequently associated with cancer, it is autoimmune-mediated, and treatment has been unsatisfactory. 3,4-Diaminopyridine enhances the release of acetylcholine. In this prospective, double-blind, placebo-controlled crossover study of 12 patients with Lambert-Eaton myasthenic syndrome (7 of whom had cancer), 3,4-diaminopyridine in doses up to 100 mg per day was effective in treating both the motor and the autonomic deficits of the syndrome. Muscle strength increased from an average of 70 percent of normal to 81 percent of normal in the upper extremities, and from 45 to 65 percent of normal in the lower extremities. The amplitudes of compound-muscle-action potentials nearly doubled, increasing from an average of 2.9 mV to 5.0 mV in the arm and from 1.6 mV to 3.1 mV in the leg. Autonomic symptoms were relieved. One patient had a seizure after 10 months of treatment, but other side effects from the drug were minimal and dose-related. We conclude that 3,4-diaminopyridine, either alone or in conjunction with other therapies, may be useful in the treatment of Lambert-Eaton myasthenic syndrome. A minor tranquilizer, ketazolam, was tested in a double-blind, randomized, crossover study of 50 patients for its effects in neurologic spasticity. The drug was compared with diazepam (widely accepted as an effective antispasticity agent) and a placebo. The patients with spasticity were almost all cases of multiple sclerosis (24) or stroke (24). Thirty-nine patients completed the study. There was not statistically significant superiority of either diazepam or ketazolam, but both relieved symptoms significantly better than the placebo, as measured clinically and by electromyographic recording of deep tendon reflexes. Ketazolam is a relatively safe and clinically effective antispasticity agent (especially for patients with multiple sclerosis). The well-known "big 3"--dantrolene sodium, baclofen, and diazepam--produce large and small problems in many individual cases; hence, ketazolam now offers a safe and clinically useful alternative. Familial hemiplegic migraine and episodic ataxia type 2 (EA2) are allelic disorders with distinct types of mutations in the CACNA1A gene. EA2 attacks are remarkably sensitive to acetazolamide, a carbonic anhydrase inhibitor. The effectiveness of acetazolamide in migraine prophylaxis is unknown.
                To evaluate the efficacy and the tolerability of acetazolamide in migraine prophylaxis.
                We compared daily oral 500 mg acetazolamide and placebo in patients with migraine in a multicentre, double-blind, randomised trial of 12 weeks duration after a run-in period of 4 weeks without treatment. Frequency of attacks at the last trial period of 4 weeks was the primary efficacy criterion. Secondary efficacy criteria were the frequency of attacks per 4 weeks, the severity and duration of attacks, the number of hours with migraine as well as the number of responders with more than 50% reduction in attack frequency.
                53 patients had been enrolled when the study was prematurely stopped because of a high number of withdrawals (34%), primarily linked to acetazolamide related side effects. Considering the primary and secondary efficacy criteria, among the 53 included patients (27 in the placebo group and 26 in the acetazolamide group), no difference between the 2 study groups could be demonstrated. The most frequent adverse events related to acetazolamide were paresthesias and asthenia.
                In this trial, migraine sufferers poorly tolerated acetazolamide given in an oral dose of 500 mg daily. No obvious prophylactic beneficial effect of acetazolamide appeared on migraine attacks. Dysfunction of N-methyl-D-aspartate (NMDA) receptor-mediated glutamatergic neurotransmission may be relevant to the pathogenesis of negative symptoms in schizophrenia. The tuberculostatic compound D-cycloserine (DCS) acts as a partial agonist at the strychnine-insensitive glycine regulatory site on the NMDA receptor complex. Dose-finding trials suggest that DCS doses of 50-100 mg/d may be beneficial in the treatment of negative symptoms in schizophrenia. Nine treatment-resistant chronic schizophrenic patients participated in a double-blind, placebo-controlled, adjuvant treatment trial with 50 mg/d DCS. Between treatment-groups differences in symptom changes were not significant. However, a significant (p<0.05) reduction in negative symptoms was registered during treatment with DCS but not placebo. Greater reductions were registered in patients with lower baseline serum glycine levels (p<0.008). No side effects were registered. These preliminary findings indicate a potential role of DCS in the treatment of negative symptoms in schizophrenia. However, the degree of symptom reduction may be modest, at least among treatment-resistant inpatients. In a double-blind comparative study, the therapeutic efficacy and safety of three centrally effective antispasmodics (Tetrazepam, Baclofen and Tizanidine) in patients suffering from multiple sclerosis with spastic motor disturbances of the lower extremities was to be examined. 47 patients of either sex at the age of 23 until 63 were allocated to one of the three therapies by means of minimization. The duration of treatment was limited to 35 days at a maximum. The dosage was optimized corresponding to the clinical symptoms. The antispasmodic efficacy and safety of the above-mentioned substances was investigated with well-established parameters and methods. The typical laboratory parameters were determined at the beginning and at the end of the study. -With reference to cloni, spasms and the muscular tonus, no systematic differences were found between the treatment groups. A previously existing clonus could not be altered decisively by the administration of the three antispasmodics, whereas the muscular tonus could comparably be decreased with all therapeutic measures. Statistically significant differences between the treatment groups were not observed. The patients of all three groups recorded a subjective sensation of relief with reference to the symptoms of spasms by the medication. As to the residual urinary volume, no relevant differences and alterations were determinated in the course of the treatment as well. With reference to undesired side effects quantitative and qualitative differences could be established, in which Tetrazepam showed the most favourable benefit/risk ratio.
The largest included study that met our inclusion criteria suggested that DCP was effective in the prevention of episodic weakness in both hypokalemic and hyperkalemic periodic paralyses. The other two studies provide some evidence that either acetazolamide or pinacidil may improve muscle strength. However we still lack sufficient evidence to provide full guidelines for the treatment of people with periodic paralysis.