Digoxin absorption

Diarrheal conditions may decrease drug absorption as a result of reduced intestinal residence time. The absorption of several drugs was decreased in response to lactose- and saline-induced diarrhea [145]. Digoxin absorption from tablets was impaired in one subject who developed chronic diarrhea as a result of x-ray treatment [146]. Abdominal radiation or the underlying disease has been shown to reduce digoxin and clorazepate absorption [147]. A dosage form that provides rapid drug dissolution (e.g., solution) may partially resolve this problem. 

WJ Jusko, DR Conti, A Molson, P Kuritzky, J Giller, R Schultz. Digoxin absorption from tablets and elixir the effect of radiation-induced malabsorption. J Am Med Assoc 230 1554-1555, 1974. 

Salphati L and Benet LZ (1998) Effects of Ketoconazole on Digoxin Absorption and Disposition in Rat. Pharmacology 56 pp 308-313. 

Kaolin-pectin [P] Decreased gastrointestinal digoxin absorption. 

Liu S, Tam D, Chen X, et al. P-glycoprotein and an unstirred water layer barring digoxin absorption in the vascularly perfused rat small intestine preparation induction studies with pregnenolone-16alpha-carbonitrile. Drug Metab Dispos 2006 34 1468-1479. 

Su SF, Huang JD. Inhibition of the intestinal digoxin absorption and exsorption by quinidine. Drug Metab Dispos 1996 24(2) 142-147. 

STATINS CARDIAC GLYCOSIDES High-dose (80 mg) atorvastatin may t digoxin levels Atorvastatin inhibits intestinal P-gp, which t digoxin absorption Watch for digoxin toxicity... 

In addition to enzyme induction, phenytoin can reduce digoxin absorption. 

In 12 healthy young adults the phosphodiesterase inhibitor cilomilast 15 mg bd for 5 days had no effect on the steady-state pharmacokinetics of digoxin, apart from a small reduction in the maximal concentration and a small increase in the time to peak (253). This was consistent with a small effect on the rate of digoxin absorption. 

Salphati L, Benet LZ. Effects of ketoconazole on digoxin absorption and disposition in rat. Pharmacology 1998 56(6) 308-13. 

The authors speculated that cisapride reduced digoxin absorption by accelerating bowel transit time. 

Digoxin is nearly completely absorbed from the gut. In some patients, absorption may be deaeased due to digoxin inactivation by gut bacteria (i.e., Eubacterium lentum) Digoxin absorption is reduced by concomitant administration of antacids, cholestyramine, kaolin/pectin, tetracycline, and neomycin. Radiation malabsorption and gastrointestinal motility drugs such as metoclopramide can also reduce absorption. ... 

Decrease gastronintestinal transit time, decreasing digoxin absorption Increases serum digoxin levels decrease digoxin dose by 50%... 

Yacobi A (1981). The assessment of intersubject variability in digoxin absorption in man from two oral dosage forms. / Clin Pharmacol 21 301-310. 

Digoxin Metoclopramide Propantheline Reduced digoxin absorption Increased digoxin absorption (due to changes in gut motility)... 

Other studies describe reductions in digoxin absorption of 11% with aluminium hydroxide, 15% with bismuth carbonate and light magnesium carbonate, and 99.5% with magnesium trisilicate. ... 

Woods MN, Ingelfinger JA. Lack of effect of bran on digoxin absorption. CUn Pharmacol Ther( 919)26, 21-3. 

Mouser B, Nykamp D, Murphy JE, Krissman PH. Effect of cimetidine on oral digoxin absorption. DICP Ann Pharmacother ( 990) 24, 286-8. 

Jordaens L, Hoegaerts J, Belpaire F. Non-interaction of cimetidine with digoxin absorption, ActaClinBelg 9Z )36, 109-10. 

Steady-state studies reflect the every-day situation much more elosely than single-dose studies, and the one cited above indieates that the total reduetion in digoxin absorption is small (15%). This is unlikely to be of clinical importance. However, if an interaction does occur the effects can seemingly be minimised by separating the dosages by 2 hours. 

Johnson BF, Bustrack JA, Urbach DR, Hull JH, Marwaha R. Effect of m etoclopran ide on digoxin absorption from tablets and capsules. Clin Pharmacol Ther (1984) 36, 724-30. 

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