Grapefruit juice consumption, effect

In a pharmacokinetic study, grapefruit juice had little effect on the absorption of levothyroxine, suggesting a clinically relevant interaction is unlikely. However, there is one case of unexplained hypothyroidism in a patient taking levothyroxine, which resolved when grapefruit juice consumption was reduced. 

Fig. 18.6. Midazolam administration with and without grapefruit juice (CFJ) treatment [41]. Midazolam (15 mg tablet) was administered to eight male subjects (average body weight 82 kg) before and after consumption of two glasses (200 mL each) of CFJ, 1 h before drug administration. QMPRPIus was used to estimate human effective permeability (12 x 10 4 cm s 1), pure aqueous water...

Lilja JJ, Kivisto KT, Backman JT, Neuvonen PJ. Effect of grapefruit juice dose on grapefruit juice-triazolam interaction repeated consumption prolongs triazolam half-life. Eur J Clin Pharmacol 2000 56(5) 411-415. 

Lilja JJ, Neuvonen M, Neuvonen PJ. Effects of regular consumption of grapefruit juice on the pharmacokinetics of simvastatin. Br J Clin Pharmacol 2004 58(l) 56-60. 

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