Orion Mite (Digoxin)

Digoxin is employed in cardiovascular conditions that affect heart contractility or rhythm.

• Heart failure: enhances myocardial contractility and reduces symptoms of congestion.
• Atrial fibrillation: slows ventricular response rate to improve rate control.
• Atrial flutter: assists in controlling ventricular rate during rhythm disturbances.

• Digoxin inhibits the Na⁺/K⁺‑ATPase pump in cardiac myocytes, leading to an increase in intracellular sodium. This alteration reduces the activity of the sodium‑calcium exchanger, causing calcium accumulation inside the cells, which strengthens myocardial contraction. Additionally, digoxin stimulates vagal tone, producing a modest reduction in heart rate and atrioventricular conduction, aiding rhythm control.

Adverse reactions to digoxin may vary in frequency and severity.

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Vomiting: occasional emesis, especially after dose changes.
• Diarrhea: loose stools without abdominal pain.
• Fatigue: generalized tiredness or weakness.
• Blurred vision: transient visual disturbances.
• Headache: mild to moderate cephalic pain.

Serious or Rare Side Effects

• Cardiac arrhythmias: potentially life‑threatening rhythm disturbances.
• Severe bradycardia: markedly reduced heart rate requiring intervention.
• Heart block: impairment of atrioventricular conduction.
• Hyperkalemia: elevated serum potassium, especially with renal impairment.
• Visual halos: yellow‑green color perception changes.
• Allergic reactions: rash, pruritus, or anaphylaxis.

Safe use of digoxin requires careful monitoring and patient assessment.

• Serum level monitoring: check digoxin concentration regularly to avoid toxicity.
• Renal function adjustment: reduce dose in patients with impaired kidney function.
• Electrolyte balance: correct hypokalemia or hypermagnesemia before initiating therapy.
• Contraindication in ventricular arrhythmia: avoid use in patients with pre‑existing ventricular tachyarrhythmias.
• Pregnancy caution: use only if potential benefit justifies potential risk to the fetus.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Digoxin interacts with several medicines that can alter its plasma concentration or cardiac effects.

Major Interactions (Avoid)

• Amiodarone: markedly increases digoxin levels, raising toxicity risk.
• Quinidine: elevates serum digoxin concentrations.
• Verapamil: enhances digoxin effect and may precipitate bradycardia.
• Spironolactone: raises digoxin levels, especially in renal impairment.
• Erythromycin: can increase digoxin exposure.

Moderate Interactions (Monitor Closely)

• Thiazide diuretics: may cause hypokalemia, enhancing digoxin toxicity.
• ACE inhibitors: can affect renal function, influencing digoxin clearance.
• Beta‑blockers: additive effects on heart rate and conduction.
• Diltiazem: moderate increase in digoxin concentration.
• NSAIDs: may reduce renal clearance of digoxin.