Treatment of myotonia with antiarrhythmic drugs. A comparative study of disopyramide and procainamide in the treatment of myotonia in myotonic dystrophy. Nifedipine in the treatment of myotonia in myotonic dystrophy. The treatment of myotonia: evaluation of chronic oral taurine therapy. A pilot controlled study of the use of imipramine to reduce myotonia. Therapy of myotonia. A double-blind evaluation of diphenylhydantoin, procainamide, and placebo. The treatment of myotonia: a controlled clinical trial. Pravastatin in acute ischaemic syndromes: results of a randomised placebo-controlled trial.
The effects of disopyramide, phenytoin, mexiletine, and tocainide were compared in 30 patients with myotonic disorders. The severity of myotonia was assessed by clinical and electromyographic criteria at the end of each treatment phase lasting four weeks. Mexiletine (MXT) and tocainide (TCD) were found to be the most potent antimyotonic agents. The antimyotonic efficacy of MXT and TCD is explained by their fast-blocking effect on voltage-dependent sodium channels in the muscle membrane. The benefits of myotonia control with pharmacological agents must be weight against the risk of therapy in the individual patient. Because of the risks of hematologic problems, TCD is not recommended by us for the treatment of myotonia. Ten patients with myotonic dystrophy were allocated at random to treatment with disopyramide and procainamide in a cross-over trial. Disopyramide was found to be at least as effective as procainamide in the relief of myotonia; and two patients who could not tolerate procainamide both tolerated disopyramide. Abnormal calcium transport may be implicated in the membrane defect in myotonic dystrophy. A single blind crossover trial of placebo (t.i.d.), nifedipine 10 mg (t.i.d.) and nifedipine 20 mg (t.i.d.), was performed in 10 patients with myotonic dystrophy. The severity of myotonia was assessed by measuring finger extension time after maximum voluntary finger flexion. A significant improvement in myotonia, after nifedipine, was recorded by this technique and supported by a subjective improvement in 50% of patients and clinical improvement of greater than 20% in five patients. Initial grip strength and muscle fatiguability measured by grip strength ergometry were not significantly altered. A double-blind, single crossover study of chronic oral taurine administration versus placebo was conducted on nine patients with dystrophia myotonica. The severity of myotonia was assessed by clinical and electromyographic criteria and by testing the sensitivity of myotonic muscles to the intra-arterial infusion of potassium chloride. Confirming the antimyotonic effect of acute parenteral taurine, chronic treatment induced significant improvement of myotonia and a decreased sensitivity to the arterial potassium load as well as an enhancement of electrolyte movements across the membrane of the studied muscles. No significant side effects were noted. It has been hypothesized that myotonic dystrophy is caused by a generalized disorder of membrane aminergic and petidergic receptors. A single uncontrolled study has suggested that the affective symptomatology and muscular disability of this disorder might be improved by tricyclic antidepressant treatment. In the present study, 12 adult patients with myotonic dystrophy (age range 18-55 yr) were treated with imipramine and placebo in a double-blind crossover paradigm. Both grip and percussion myotonia were significantly improved by imipramine treatment independent of change in depressive symptomatology. Serum drug levels revealed nonlinear elimination kinetics for imipramine in this patient population. nan nan Therapy with individual 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) has been shown conclusively to diminish coronary event rates and mortality in both primary and secondary prevention. To date, scant attention has been paid to whether initiation of such regimens in the hospital phase of acute coronary syndromes might confer cardioprotective benefits. The purpose of this study was to determine the safety and tolerability of early initiation of statin therapy in patients with acute coronary syndromes. In this randomised, double-blind, three-month, pilot study, 100 patients with acute myocardial infarction or unstable angina and low-density lipoprotein cholesterol > 3.5 mmol/l were randomly assigned to pravastatin 40 mg daily or placebo initiated within 48 hours of hospital admission. Pravastatin proved safe and well tolerated in these patients, who were well matched at baseline. No statistically significant differences in death, MI and drug-related adverse events were observed in the pravastatin group compared with control subjects. This pilot study shows that therapy with pravastatin early after an acute coronary event is safe and well tolerated. Larger, long-term studies are needed to confirm these findings.
Due to insufficient good quality data and lack of randomised studies, it is impossible to determine whether drug treatment is safe and effective in the treatment of myotonia. Larger, well-designed randomised controlled trials are needed to assess the efficacy and tolerability of drug treatment for myotonia.