Digoxin adverse reaction

Digoxin adverse reactions are dose-dependent and occur at doses higher than those needed to achieve a therapeutic effect. Cardiac adverse reactions accounted for approximately 50%, Gl disturbances for approximately 25%, and CNS and other toxicity for approximately 25% of these adverse reactions. However, available evidence suggests that the incidence and severity of digoxin toxicity has decreased substantially in recent years. 

Adverse reactions to digoxin include anorexia, vomiting, diarrhea, dizziness, headaches, visual disturbances, and cardiac arrhythmias. Allergic reaction such as urticaria, skin emptions, fever, and edema have been reported (87). 

Because some patients are more sensitive to side effects with digoxin, the dosage is selected carefully and adjusted as the clinical condition indicates. Adverse reactions were more common and severe in past years before careful attention to weight, renal function, and the concurrent administration of certain medications was given. The incidence and severity of digoxin toxicity has decreased significantly in recent years. 

Monitoring a patient s pulse rate is second nature when the patient is in an acute caretadlity. However, when the patient goes home with digoxin, he or she will need to monitor the pulse rate to prevent possible adverse reactions. The nurse teaches the patient to perform the following steps ... 

Aminosalicylic acid may affect isoniazid, digoxin, and vitamin B- 2-Adverse Reactions... 

Etodolac This drug has effects similar to those of the other NSAIDs. Gastrointestinal problems may be less common. However, other adverse effects such as fluid retention and abnormal kidney and liver function have been reported. Etodolac may increase the serum levels and thus raise the risk of adverse reactions caused by digoxin, lithium, methotrexate, and enhance the nephrotoxicity of cyclosporine. 

Despite these technical advances, adverse reactions still occur frequently with digoxin, phenytoin, and many other drugs for which drug concentration measurements are routinely available. The persistence in contemporary practice of dose-related toxicity with these drugs most likely reflects inadequate understanding of basic pharmacokinetic principles. This is illustrated by the following case history (5) ... 

Of 603 adults aged 79 years, of whom 59% were women and 18% African-American, 376 patients (62%) were discharged taking digoxin, and 223 (37%) had no indication for its use, based on the absence of left ventricular systolic dysfunction or atrial fibrillation (20). After adjustment for various factors, prior digoxin use (OR =11 95% Cl = 5.7, 23) and pulse over 100/minute (OR = 2.33 95% Cl = 1.1, 4.9) were associated with inappropriate digoxin use. Unfortunately, the authors did not report the frequency of adverse effects, and it is not therefore clear whether patients in whom digoxin is used inappropriately are more or less likely to suffer adverse reactions. 

Secondary side effect An adverse reaction that is an indirect consequence of a drug s action but is nevertheless predictable (e.g., lowered potassium with diuretics, nausea with Digoxin, dry mouth with antidepressants). 

An 86-year-old man taking fiirosemide, digoxin, domperidone and sustained-release theophylline developed signs of theophylline toxicity when amiodarone 600 mg daily was given. After 9 days his serum theophylline levels had doubled, from about 16.8 to 35 mg/L. The toxicity disappeared when the theophylline was stopped. The reason for this adverse reaction is not understood but it has been suggested that amiodarone may reduce the metabolism of the theophylline by the liver. This is an isolated case and its general importance is uncertain. More study is needed. 

Metoclopramide Metoclopramide causes release of acetylcholine from cholinergic nerve terminals and can cause cholinergic adverse reactions, including bradydysrhyth-mias. In one case a patient had 22 episodes of bradycardia/asystole after taking metoclopramide and digoxin for several weeks. 

Some examples of this approach are the linkage of adverse outcomes of inappropriate anticoagulation (stroke, myocardial infarct, or death widiin 6 days) to the measurement of prothrombin times and the linkage of adverse effects of digoxin therapy (death or hospitalization caused by insufficiency, overdose, or drug reaction) with the measurement of digoxmd ... 

One in 10 admissions to acute geriatric units was caused or partly caused by adverse dmg reactions. The dmgs involved most commonly were benzodiazepines, warfarin, digoxin and nonsteroid anti-inflammatories (Denham and Barnet, 1998). Tamblyn (1996), in his review article, cited reports of adverse events causing 5-23% of hospitalizations, nearly 2% of ambulatory visits and 1 in 1000 deaths in the general population. These rates increase in the elderly. Errors in... 

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