Digitalis clinical effects

Calcium is contraindicated in patients with hypercalcemia or ventricular fibrillation and in patients taking digitalis. Calcium is used cautiously in patients with cardiac disease. Hypercalcemia may occur when calcium is administered with the thiazide diuretics. When calcium is administered with atenolol there is a decrease in Hie effect of atenolol, possibly resulting in decreased beta blockade. There is an increased risk of digitalis toxicity when digitalis preparations are administered with calcium. The clinical effect of verapamil may be decreased when the drug is administered with calcium. Concurrent ingestion of spinach or cereal may decrease file absorption of calcium supplements. 

Pharmaceuticals of plant origin also form part of rational drug therapy in science-oriented medicine. They are used in the treatment of certain defined diseases and complaints. The more carefully the various pharmacological characteristics of phytogenic remedies are elucidated, the more reliably their clinical effects can be evaluated (e. g. digitalis, rauwolfia, hyo-scyamine, senna). This is also true of the phytotherapeutic preparations used in hepatology. 

Digitalis has effects on sex hormones. It causes increased serum concentrations of follicle-stimulating hormone (FSH) and estrogen and reduced concentrations of luteinizing hormone (LH) and testosterone (89-92). These effects are probably not related to any direct estrogen-like structure of digitalis (despite structural similarities), but rather to an effect involving the synthesis or release of sex hormones. There are three possible clinical outcomes of these effects. 

Propranolol has been studied most carefully in experiments and in clinics. It is used for ventricular tachycardia, arrhythmia caused by digitalis drug overdose, or as a result of thy-rotoxosis or excess catecholamine activity. Despite the fact that there are a number of )8-adrenoblockers, propranolol is considered the first choice of drugs although other blockers of calcium blockers can be just as effective. 

Clinically, tachyarrhythmias associated with digitalis excess (including supraventricular and ventricular extrasystoles) and ventricular tachycardia have been suppressed by propranolol. Although propranolol is highly effective in the treatment of digitalis-induced arrhythmias, phenytoin and Udocaine are preferred. 

D. Chemical Use Classes. This includes the toxicology aspects of the development of new chemicals for commercial use. In some of these use classes, toxicity, at least to some organisms, is a desirable trait in others, it is an undesirable side effect. Use classes are not composed entirely of synthetic chemicals many natural products are isolated and used for commercial and other purposes and must be subjected to the same toxicity testing as that required for synthetic chemicals. Examples of such natural products include the insecticide, pyrethrin, the clinical drug, digitalis, and the drug of abuse, cocaine. 

Withering was unaware that dropsy was caused by cardiac insufficiency. In common with his time, he believed that the kidney was responsible for dropsy (peripheral fluid accumulation) and was therefore the site of action of Digitalis in the condition. Nevertheless, his clinical observations were precise Let the medicine therefore be given in doses, and at the intervals mentioned above let it be continued until it either acts on the kidneys, the stomach, the pulse or the bowels let it be stopped upon the first appearance of any one of these effects, and I will maintain that the patient will not suffer from its exhibition, nor the practitioner be disappointed in any reasonable expectation. ... 

Although the first-pass effect is a major source of species variation in systemic availability of orally administered drugs that undergo extensive hepatic metabolism, another important source of variation is metabolism by ruminal microorganisms. Some drugs (nitroxynil, chloramphenicol, digitalis glycosides) are metabolized in the rumen to such an extent that parenteral administration is required for clinical efficacy. 

Margolis JR, Strauss HC, Miller HC, Gilbert M, Wallace AG. Digitalis and the sick sinus syndrome. Clinical and electro-physiologic documentation of severe toxic effect on sinus node function. Circulation 1975 52(l) 162-9. 

It is noteworthy that calcium inhibitory compounds with the ability to inhibit %a+ possess the most potent antiarrhythmic activity against both experimental and clinical arrhythmias (126). For example, nifedipine exerts minimal, if any, antiarrhythmic effect against ischemic induced arrhythmias in intact animals (6, 87, 131). Diltiazem and perhexiline, on the other hand, demonstrate variable antiarrhythmic effects dependent upon their dose and the mechanism responsible for arrhythmia production (ischemia, hypoxia, digitalis, aconitine) (102, 126, 151, 152). Only verapamil, which has been investigated in the largest number of experimental and clinical trials, has demonstrated consistent antiarrhythmic activity against cardiac arrhythmias regardless of cause (155) ... 

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