Effect of Magnesium—Aluminum Hydroxide and Kaolin—Pectin on Absorption of Digoxin from Tablets and Capsules

Abstract

Twelve healthy fasting volunteers received two 0.2-mg digoxin capsules or tablets with 60 ml water, 60 ml Maalox, or 60 ml Kaopectate in a randomized, single-dose, six-way crossover study. Concentrations of digoxin in multiple plasma samples and in all urine collected during the 24 hours after each dose were determined by radioimmunoassay. Compared to the water treatment, administration of both tablets and capsules with Maalox or Kaopectate reduced the peak digoxin plasma concentrations but did not significantly influence the time of peak concentration. Neither Maalox nor Kaopectate influenced the area under the 24-hour plasma concentration--time curve for either tablets or capsules. However, 24-hour urinary recovery of digoxin from tablets tended to be reduced by Maalox and Kaopectate; this was not the case with capsules. Digoxin capsules may have an advantage over currently available tablets in clinical situations requiring digoxin coadministration with nonabsorbable gastrointestinal preparations.

Adverse Effects of Drugs Used in the Management of Constipation and Diarrhoea

“…Kaolin-pectin reduces absorbtion of some drugs, such as digoxin (Allen et al 1981;Brown & Juh11976) and some antibiotics (Salim et al 1983), although this may not be clinically significant.…”

Drug Interactions Involving Digitalis Glycosides

“…Since physical adsorption underlies this interaction, the relative times of drug administration are critical in determining the extent to which digoxin absorption will be impaired. As with liquid antacids, concurrently administered kaolin-pectin causes less reduction in digoxin bioavailability when digoxin capsules are used instead of tablets (Allen et al, 1981). As with liquid antacids, concurrently administered kaolin-pectin causes less reduction in digoxin bioavailability when digoxin capsules are used instead of tablets (Allen et al, 1981).…”

Drug Interactions and Adverse Reactions

“…Aminoglycoside antibiotics vancomycin possible nephrotoxicity and ototoxicity (possibly additive) [60] antihistamine, H 2blockers decreased cimetidine, ranitidine and nizatidine effect (decreased absorption) [61] benzodiazepines decreased oral clorazepate effect (decreased absorption) [62] Antacids -adrenergic blockers decreased oral effect (decreased absorption) [63] cephalosporins possible decreased effect (decreased absorption) [64] corticosteroids decreased oral corticosteroid effect (decreased absorption) [65] digoxin decreased digoxin effect (possible decreased absorption) [66] hypoglycaemics possible hypoglycaemia (increased absorption and accelerated insulin response) [67] quinidine possible quinidine toxicity (decreased renal excretion) [68] quinine possible quinine toxicity (decreased renal excretion) [69] tetracyclines decreased oral tetracycline effect (decreased absorption) [70] vitamin C possible aluminium toxicity (possibly increased absorption) [71] vitamin D possible bone toxicity with aluminium compounds (increased deposition of aluminium in bone, possibly due to increased absorption) [72] Antifungals (griseofulvin) decreased anticoagulant effect (mechanism not established) [73] antihistamine, H 2blockers increased anticoagulant effect (decreased metabolism) [74] barbiturates decreased anticoagulant effect (increased metabolism) [75] Anticoagulants, oral carbamazepine decreased anticoagulant effect (increased metabolism) [76] Drug interactions and adverse reactions 317 chloral hydrate increased anticoagulant effect (displacement from binding) [77] cholestyramine decreased anticoagulant effect (binding of drug in intestine) [78] disulfiram increased anticoagulant effect (decreased metabolism) [79] fluoroquinolones increased anticoagulant effect (mechanism not established) [80] glutethimide decreased anticoagulant effect (increased metabolism) [81] macrolide antibiotics increased anticoagulant effect (possibly decreased metabolism) [82] nalidixic acid increased anticoagulant effect (displacement from binding) [83] NSAIDs increased bleeding risk (inhibition of platelets, other mechanisms) [84] phenytoin phenytoin toxicity (decreased metabolism) …”