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Indian Journal of Dermatology, Venereology and Leprology
Medknow Publications on behalf of The Indian Association of Dermatologists, Venereologists and Leprologists (IADVL)
ISSN: 0378-6323 EISSN: 0973-3922
Vol. 69, Num. 5, 2003, pp. 363
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Untitled Document
Indian Journal of Dermatology, Venerelogy & Leprology, Vol 69, No.
5 ,Sept-Oct, 2003, pp. 363
Letters to Editor
Grapefruit juice vs. grape juice
M. J. Cyriac
Department of Dermatology and Venereology, Medical College,
Kottayam, India. E-mail: drmjcyriac@hotmail.com
Code Number: dv03065
Sir,
While reading the article `Drugs
in dermatological practice: Relationship to food'1 I saw that
it is advised not to take cyclosporin with grape juice. I would like to point
out that it is grapefruit juice and not grape juice which produces elevated
serum concentrations of cyclosporin.2 In fact many western hospitals
have removed grapefruit juice from their inpatient menus to avoid the risk
of drug interactions.
Grapefruit (Citrus X paradisi) is a citrus fruit which inhibits the CYP3A4
pathway in the small intestinal wall when either fresh or frozen grapefruit
is eaten or grapefruit juice is drunk.3 This inhibition may be due
to Bergamottin, a furocoumarin compound or due to other flavonoids present
in it. This results in elevation of serum concentrations of all drugs which
are metabolized via the CYP3A4 pathway including cyclosporine, felodipine,
nifedipine, saquinavir, midazolam, triazolam, terazosin, ethinyloestradiol,17-beta
oestradiol, prednisone, lovastatin, simvastatin etc. Absence of 6,7-Dihydrobergamottin
in orange juice probably accounts for the absence of CYP inhibitory effects.4 Pronounced
elevation of the maximal plasma concentrations are seen with drugs that have
high first pass metabolism (metabolism of a drug during its passage from the
site of absorption into the systemic circulation- at the small intestinal wall
and in the liver in case of orally administered drugs). In fact, this inhibitory
effect of grapefruit juice on the metabolism of cyclosporin may be used to
achieve therapeutic plasma concentrations of the drug at lower dosage levels
than usual, but this is not recommended as the effect varies with different
batches of grapefruit.
References
- Smitha Prabhu, SD Shenoi. Drugs in dermatological practice:
Relationship to food. Indian J Dermatol Venereol Leprol 2003;69:305-6
- Shapiro
LE, Shear NH. Drug Interactions. In: Wolverton SE, editor. Comprehensive
Dermatological Drug Therapy. WB Saunders; 2001. p. 848-71.
- Roller L. Drugs
and grapefruit
juice(letter). Clin Pharmacol Ther 1998;1:87.
- Hollander AA, van der Woude
FJ, Cohen AF. Effect of grapefruit juice on blood cyclosporin concentration
(letter). Lancet 1995;346:123.
Copyright 2003 - Indian Journal of Dermatology, Venereology & Leprology.
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