Kaolin Digoxin

Which of the following best describes the mechanism of kaolin-pectin s interaction with digoxin ... 

The answer is d. (Hardman, pp 816-818.) Digoxin levels can be reduced by 25% with concomitant use of kaolin-pectin by an unknown mechanism that decreases GI absorption. 

The absorption of some drugs may also be reduced if they are given with adsorbents such as charcoal or kaolin, or anionic exchange resins such as colestyramine or colestipol. The absorption of propranolol, digoxin, warfarin, tricyclic antidepressants, ciclosporin and levothyroxine is reduced by colestyramine. 

Kaolin-pectin [P] Decreased gastrointestinal digoxin absorption. 

DIGOXIN ANTIDIARRHOEALS -KAOLIN Possibly l levels of digoxin 1 absorption Separate doses by at least 2 hours... 

Kaolin can reduce the absorption and efficacy of other drugs, notably drugs acting on the heart, such as digoxin and beta-blockers. 

The adsorbent properties of kaolin may influence the absorption of other orally administered drugs. Drugs rraortedly affected by kaolin include amoxicillin ampicillin cimeti-dine digoxin lincomycin phenytoin and tetracycline. 

Albert KS, Ayres JW, Di Santo AR, et al. Influence of kaolin-pectin suspension on digoxin bioavailability. J Pharm Sci 1978 67 1582-1586. 

Drug Interactions - Absorption half-life of the antibiotic, clindamycin, was prolonged in human subjects when a kaolin-pectin antidiarrheal suspension was coadministered, although the extent of absorption remained the same. On the other hand, both the rate and the extent of absorption of digoxin were lower when it was coadministered with the same kaolin-pectin suspension. Physical absorption and alterations in gut transit time appeared to partly explain the findings. 

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. ... 

Brown DD, Juhl RP, Lewis K, Schrott M, Bartels B. Decreased bioavailability of digoxin due to antacids and kaolin-pectiiL NEnglJMed (1976) 295,1034-7. 

Albert KS, Elliott WJ, Abbott RD, Gilbertson TJ, Data JL. Influence of kaolin-pectin suspension on steady-state plasma digoxin levels. J Clin Pharmacol (1981) 21, 449-55. 

Allen MD, Greenblatt DJ, Harmatz JS, Smith TW. Effect of magnesium aluminum hydroxide and kaolin-pectin on absorption of digoxin from tablets and capsules. J Clin Pharmacol (1981) 21,26-30. 

Plasma digoxin levels can be reduced by kaolin-pectin, but the reduction is small and probably of minimal clinical importance. 

The concurrent use of kaolin-pectin suspension and digoxin reduced the peak plasma digoxin levels of 7 patients by 36%, while the AUCq 24 was reduced by 15%. Conversely, when two doses of kaolin-peetin were taken, the first 2 hours before and the other 2 hours after the digoxin, no significant changes were seen. ... 

Two single-dose studies have found 42% and 62% reductions in the bioavailability of digoxin caused by kaolin-pectin. Another study found an interaction with digoxin tablets but not with digoxin capsules. ... 

Not understood. The digoxin may possibly become adsorbed onto the kaolin so that less is available for absorption. Another possibility is that the kaolin reduces the motility of the gut, which normally increases mixing and brings the digoxin into contact with the absorbing surface. 

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