LANOXICAPS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LANOXICAPS (LANOXICAPS).
Inhibition of Na+/K+-ATPase pump, leading to increased intracellular sodium and calcium, positive inotropy, and increased vagal tone.
| Metabolism | Primarily renal excretion as unchanged drug; minor hepatic metabolism via CYP3A4 and glucuronidation. |
| Excretion | Digitoxin is primarily excreted via the kidneys (approx. 70-80%) as unchanged drug and metabolites; the remainder undergoes biliary/fecal elimination (approx. 20-30%). |
| Half-life | Terminal elimination half-life is approximately 5-7 days (120-168 hours) in patients with normal renal function; prolonged in renal impairment, necessitating dose adjustment. |
| Protein binding | Digitoxin is approximately 90-97% bound to serum proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 0.6 L/kg, indicating extensive tissue binding and distribution; the large Vd reflects accumulation in tissues like myocardium and skeletal muscle. |
| Bioavailability | Oral bioavailability is virtually 100% (90-100%) for Lanoxicaps (digitoxin), with consistent absorption from the gastrointestinal tract. |
| Onset of Action | Oral: Onset of action occurs within 0.5-2 hours; peak effect is achieved in 2-6 hours. Intravenous: Onset within 15-30 minutes; peak effect in 1-4 hours. |
| Duration of Action | Duration of action is 3-7 days after oral administration due to slow elimination; clinical effects may persist for several days after discontinuation. |
| Molecular Weight | 781 |
0.125-0.25 mg orally daily, initially 0.25 mg daily in divided doses 3-4 times daily, maintenance 0.125-0.25 mg daily.
| Dosage form | CAPSULE |
| Renal impairment | For eGFR <50 mL/min, reduce dose by 50% or extend dosing interval: eGFR 35-50 mL/min: 0.125 mg every 24-48 hours; eGFR 10-34 mL/min: 0.125 mg every 48-72 hours; eGFR <10 mL/min: 0.125 mg every 72-96 hours. |
| Liver impairment | Severe hepatic impairment (Child-Pugh class C) requires dose reduction by 50-75%; monitor digoxin levels. Avoid in fulminant hepatitis. |
| Pediatric use | Neonates: 4-6 mcg/kg/day; Infants: 6-10 mcg/kg/day; Children 1-5 years: 10-15 mcg/kg/day; Children 6-12 years: 8-10 mcg/kg/day; Adolescents: 3-5 mcg/kg/day. All doses given orally. |
| Geriatric use | Start at lower dose (0.0625-0.125 mg daily) due to reduced renal function and lean body mass; monitor serum creatinine and digoxin levels. |
| 1st trimester | Use only if clearly needed. Fetal bradycardia and low birth weight are reported. |
| 2nd trimester | Use only if clearly needed. Fetal bradycardia and low birth weight are reported. |
| 3rd trimester | Use only if clearly needed. Fetal bradycardia and low birth weight are reported. |
Clinical note
Comprehensive clinical and safety monograph for LANOXICAPS (LANOXICAPS).
| Placental transfer | Crosses placenta; fetal serum concentrations may be similar to maternal. |
| Breastfeeding | Excreted into breast milk in low amounts; not expected to cause adverse effects in infants. Monitor infant for bradycardia, poor feeding, and weight gain. |
| Lactation Rating |
■ FDA Black Box Warning
Toxicity: Narrow therapeutic index; monitor serum levels; avoid in patients with ventricular fibrillation or outflow obstruction.
| Serious Effects |
Hypersensitivity to digitalis glycosidesVentricular fibrillationWolff-Parkinson-White syndrome with atrial fibrillationSecond- or third-degree AV block (in absence of pacemaker)Idiopathic hypertrophic subaortic stenosis
| Precautions | Monitor for digitalis toxicity (anorexia, nausea, visual disturbances, arrhythmias). Adjust dose in renal impairment, hypokalemia, hypomagnesemia, hypercalcemia, and hypothyroidism. |
| Food/Dietary | High-fiber foods (bran, oats) and certain foods containing pectin can reduce digoxin absorption; take Lanoxicaps on an empty stomach or at least 1 hour before or 2 hours after meals. St. John's Wort may decrease digoxin levels. Avoid licorice root, which can cause hypokalemia and increase toxicity. Consistent dietary potassium intake is important; avoid potassium supplements unless directed. |
Loading safety data…
| L2 |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: digitalis glycosides cross placenta; animal studies show fetotoxicity, but no adequate human data. Second/third trimester: risk of fetal bradycardia, low birth weight; therapeutic levels near toxic for fetus. Use only if maternal benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal digoxin levels (therapeutic range 0.5–2 ng/mL), ECG for arrhythmias, renal function, electrolytes (K+, Mg2+, Ca2+). Fetal: heart rate monitoring (avoid bradycardia), serial ultrasound for growth restriction. |
| Fertility Effects | No direct adverse effects on human fertility reported. In animal studies, high doses caused decreased spermatogenesis and ovarian dysfunction, but clinical significance unknown. |
| Clinical Pearls | Lanoxicaps (digoxin) has a high bioavailability (90-100%) compared to standard digoxin tablets; adjust dose when switching formulations to avoid toxicity. Monitor renal function and electrolytes (especially potassium, magnesium, calcium) closely; hypokalemia increases digoxin toxicity risk. Digoxin toxicity can present with arrhythmias (e.g., bidirectional ventricular tachycardia, atrial tachycardia with block) and visual disturbances (yellow-green halos). Use digoxin-specific Fab fragments for life-threatening toxicity. Therapeutic drug monitoring: draw levels at least 6-8 hours after dose; target 0.5-0.9 ng/mL for heart failure, 0.8-2.0 ng/mL for atrial fibrillation. |
| Patient Advice | Take exactly as prescribed; do not miss doses or double up. If a dose is missed, skip it unless close to next dose. · Do not switch between Lanoxicaps and standard digoxin tablets without your doctor's approval due to different absorption. · Report symptoms of toxicity: nausea, vomiting, diarrhea, confusion, visual changes (blurred vision, yellow-green halos), or irregular heartbeat. · Keep regular appointments for blood tests to monitor digoxin levels, kidney function, and electrolytes. · Avoid over-the-counter medications, especially antacids, kaolin-pectin, and some laxatives, which can affect absorption. · Maintain consistent dietary intake of potassium-rich foods (bananas, oranges) and avoid extreme changes in diet. |