Digoxin capsules

Digoxin injection is frequently used to achieve rapid digitalization, with conversion to digoxin tablets or capsules for maintenance therapy. If patients are switched from IV to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Pharmacology). 

Capsules - A single initial dose of 400 to 600 meg (0.4 to 0.6 mg) digoxin oapsules usually produoes a deteetable effeet in 0.5 to 2 hours that beoomes maximal in 2 to 6 hours. Additional doses of 100 to 300 meg (0.1 to 0.3 mg) may be given oautiously at 6- to 8-hour intervals until elinieal evidenoe of an adequate effeet is noted. The usual amount of the oapsules that a 70 kg patient requires to aohieve 8 to 12 meg/kg peak body stores is 600 to 1000 meg (0.6 to 1 mg). 

Capsules Because of the more complete absorption of digoxin from soft capsules, recommended oral doses are only 80% of those for tablets and elixir. Because the significance of the higher peak serum concentrations associated with once daily capsules is not established, divided daily dosing is presently recommended for the following ... 

Usual Digoxin Solution-Filled Capsule Daily Maintenance Dose Requirements (meg)... 

Usual Digitalizing and Maintenance Dosages for Digoxin Capsules in Children with Normal Renal Function Based on Lean Body Weight ... 

IV digitalizing doses are the same as digitalizing doses of digoxin capsules. Divided daily dosing is recommended for children younger than 10 years of age. 

Absorption - Following oral administration, peak serum concentrations of digoxin occur at 1 to 3 hours. Absorption of digoxin from the tablets has been demonstrated to be 60% to 80% complete compared with an identical IV dose of digoxin (absolute bioavailability) or capsules (relative bioavailability). 

Digoxin capsules (Lanoxicaps) have greater bioavailability than digoxin tablets. 

Brown DD, Schmid J, Long RA, Hull JH. A steady-state evaluation of the effects of propantheline bromide and cholestyramine on the bioavailability of digoxin when administered as tablets or capsules. J Clin Pharmacol 1985 25(5) 360-4. 

Johnson, B.F. Mcauley, P.V. Smith, P.M. French, J.A.G. The effects of storage upon in vitro and in vivo characteristics of soft gelatin capsules containing digoxin. J. Pharm. Pharmacol. 1977, 29, 576-578. 

Mallis, G.I. Schmidt, D.H. Lindenbaum, J. Superior bioavailability of digoxin solution in capsules. Clin. Pharmacol Ther. 1975, 18, 761-768. 

Lindenbaum, J. Greater bioavailability of digoxin solution in capsules studies in the postprandial state. Clin. Pharmacol. Ther. 1977, 21, 278-282. 

A mixture of PEG 400, propylene glycol, and 8% ethanol solubilizes 50, 100 or 200 pg of digoxin in Lanoxicap soft gelatin capsules. The absolute oral bioavailability of digoxin from the Lanoxicap soft gelatin capsules is 90-100%, compared to 60-80% for the tablets. The dose of digoxin is 50-350 pg per day, which is one to three capsules. 

Maenpaa H, Manninen V, Heinonen OP (1987) Comparison of the digoxin marker with capsule counting and compliance questionnaire methods for measuring compliance to medication in a clinical trial. Eur Heart J 8 (suppl I) 39 3. 

Other bioavailability studies have not found a significant interaction between digoxin capsules and aluminium/magnesium hydroxide. ... 

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