digoxin and Dizziness

A 20-day, nonrandomized, open-label, placebo-controlled study was performed to investigate whether concomitant administration of tamsulosin (0.8 mg) affects the pharmacokinetic and safety profile of intravenous digoxin (0.5 mg) in healthy subjects. Ten healthy subjects aged 21-39 years received a single oral dose of placebo on study days 1-8 and tamsulosin on days 9-18. Tamsulosin was initiated at 0.4 mg/day and the dose was increased to 0.8 mg/day from day 11. On days 2 and 15, subjects received a single intravenous dose of digoxin (0.5 mg). Safety monitoring was carried out throughout the study. Following digoxin administration, blood was drawn and urine collected over a 96-h period for pharmacokinetic determinations. Plasma tamsulosin concentrations were measured at regular intervals after dosing on day 15. The digoxin pharmacokinetic parameters with and without concomitant tamsulosin were compared. No significant difference was observed, and no irregularity was found in the plasma tamsulosin concentration data. Six subjects experienced adverse events while receiving placebo and seven while on tamsulosin. The most frequent adverse event was mild dizziness reported by four subjects. Moderate chest pain was reported in two subjects, but this was not considered to be related to the administration of the study medications. Some significant changes in vital signs were observed; however, none was accompanied by symptoms of medical concern. These changes were not temporally related to the administration of study drugs. Thus, concurrent administration of digoxin with tamsulosin did not produce any change in the pharmacokinetics of digoxin and the safety profile was acceptable. As reflected in the prescribing information for tamsulosin, no adjustment in tamsulosin dosing is required when it is administered concomitantly with digoxin.

Topics: Administration, Oral; Adrenergic alpha-Antagonists; Adult; Anti-Arrhythmia Agents; Digoxin; Dizziness; Female; Humans; Infusions, Intravenous; Male; Placebos; Sulfonamides; Tamsulosin

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Topics: Adult; Baroreflex; Blood Pressure; Cardiotonic Agents; Cholinesterase Inhibitors; Digoxin; Dizziness; Female; Heart Rate; Humans; Hypovolemia; Outcome Assessment, Health Care; Patient Positioning; Postural Orthostatic Tachycardia Syndrome; Pyridostigmine Bromide; Sympathetic Nervous System

Topics: Adult; Atrioventricular Block; Bradycardia; Comfrey; Digitalis; Digoxin; Dizziness; Electrocardiography; Humans; Male; Nausea; Phytotherapy; Plant Leaves; Vision Disorders; Vomiting

Topics: Aged; Anti-Arrhythmia Agents; Atrial Fibrillation; Digoxin; Dizziness; Electrocardiography; Humans; Immunoglobulin Fab Fragments; Kidney Failure, Chronic; Male; Muscle Weakness; Vision Disorders

Thirty-two patients with atrial fibrillation and normal ventricular rates who complained of dizziness or loss of consciousness underwent 24-hour ambulatory electrocardiographic monitoring. A control group of 25 patients in atrial fibrillation but without symptoms of dizziness or loss of consciousness was likewise investigated. All patients remained in atrial fibrillation; periods of ventricular standstill (mean, 2.9; range, 1.8-8.0) were present in 31 symptomatic patients but in only three of the control patients (mean, 1.9 s; range, 1.7-2.4). Twenty-three symptomatic patients with pauses greater than or equal to 2.0 s received a demand pacemaker. Following pacing, nineteen became completely asymptomatic; four patients continued to have dizziness but three of these, who also experienced syncope, no longer did so (mean follow-up, 13 months; range, 6-30). It is suggested that ventricular standstill may commonly occur in patients with controlled atrial fibrillation who complain of dizziness or syncope and that the majority will benefit from permanent cardiac pacing.

Topics: Adrenergic beta-Antagonists; Adult; Aged; Aged, 80 and over; Atrial Fibrillation; Chronic Disease; Combined Modality Therapy; Digoxin; Dizziness; Electrocardiography; Female; Heart Block; Heart Ventricles; Humans; Male; Middle Aged; Monitoring, Physiologic; Pacemaker, Artificial; Syncope