Prevention of amlodipine absorption by activated charcoal: effect of delay in charcoal administration |
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Authors: | Kari Laine,Kari T. Kivistö ,Into Laakso,Pertti J. Neuvonen |
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Affiliation: | Department of Pharmacology and Clinical Pharmacology, University of Turku, Turku, Finland;Department of clinical Pharmacology, University of Helsinki, Helsinki, Finland;Department of Pharmacy, University of Helsinki, Helsinki, Finland |
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Abstract: | Aims The purpose of this study was to investigate the effect of activated charcoal on the absorption of amlodipine, with special reference to delayed charcoal administration. Methods Thirty-two healthy volunteers, eight subjects in four parallel groups, ingested 10 mg of amlodipine on an empty stomach. Activated charcoal (25 g in 300 ml of water) was ingested either immediately afterwards or 2 h or 6 h after amlodipine, or amlodipine was ingested with 300 ml of water only (control). Plasma concentrations and the cumulative excretion of amlodipine into urine were measured by GC-MS for 96 h and 72 h, respectively. In addition, adsorption of amlodipine to charcoal was studied in vitro . Results Activated charcoal administered immediately after amlodipine reduced the amlodipine AUC(0,96 h) and the 72-h urinary excretion by 99% ( P <0.0005). After a delay of 2 h in charcoal administration the AUC(0,96 h) was reduced by 49% ( P =0.001), but after a delay of 6 h the reduction was 15% only ( P =NS). At a charcoal: drug ratio of 5:1, about 90% of amlodipine was adsorbed by charcoal in vitro; at ratios of 10:1 and 20:1, adsorption was practically complete. Conclusions Activated charcoal almost completely prevented amlodipine absorption when administered immediately after amlodipine ingestion. Charcoal also markedly reduced amlodipine absorption when given 2 h after amlodipine; in amlodipine overdose, administration of charcoal may be beneficial even later. We conclude that administration of activated charcoal is the method choice to prevent absorption of amlodipine in amlodipine overdose. |
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Keywords: | amlodipine absorption charcoal poisoning |
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