melatonin/caffeine interaction

[Guest guest]

I was just checking interactions of my meds (thinking of adding a new

one) and ran across this tidbit. (checkmymeds.com)

> Oral caffeine may significantly increase the bioavailability of

> melatonin. The proposed mechanism is inhibition of CYP450 1A2

> first-pass metabolism. After administration of melatonin 6 mg and

> caffeine 200 mg orally (approximately equivalent to 1 large cup of

> coffee) to 12 healthy subjects, the mean peak plasma concentration

> (Cmax) of melatonin increased by 137% and the area under the

> concentration-time curve (AUC) increased by 120%. The metabolic

> inhibition was greater in nonsmokers (n=6) than in smokers (n=6). The

> greatest effect was seen in subjects with the *1F/*1F genotype (n=7),

> whose melatonin Cmax increased by 202%. The half-life did not change

> significantly. The clinical significance of this interaction is unknown.

sol