Caffeine Estrogens

A large number of molecules have provided experimental evidence of neuroprotection in in vitro and in vivo models of Parkinson s disease and many of these putative neuroprotective substances are now the objects of clinical trials. Recently, a team of experts has identified potential neuroprotective agents to be tested in pilot studies [4]. Twelve compounds have been considered for clinical trials caffeine, coenzyme Q 10, creatine, estrogen, GPI1485, GM-1 ganglioside, minocycline, nicotine, pramipexole, ropinirol, rasagiline, and selegiline (for individual discussion see [4]). 

Del Rio, G., Menozzi, R., Zizzo, G., Avogaro, A., Marrano, P. and Velardo, A., Increased cardiovascular response to caffeine in perimenopausal women before and during estrogen therapy. Eur J Endocrinol 135(5), 598-603, 1996. 

Drugs nitroglycerine, hydralazine, oral contraceptives, reserpine, theophylline, digitalis, estrogens, ergotamine, corticosteroids, or caffeine withdrawal... 

B. Pharmacokinetics. Caffeine is rapidly and completely absorbed orally with a volume of distribution of 0.7-0.8 L/kg. Its elimination half-life is approximately 4-6 hours but can range from 3 hours in healthy smokers to 10 hours in non-smokers after overdose the half-life may be as long as 15 hours. In infants less than 2-3 months old, metabolism is extremely slow and the half-life may exceed 24 hours. (See also Table 11-59.) Caffeine is metabolized in the liver by cytochrome P-450, primarily the CPY 1A2 isoenzyme, and is subject to several potential drug interactions, including inhibition by estrogens, cimeti-dine, norfloxacin, and alcohol. Tobacco (and marijhuana) smoking accelerates caffeine metabolism. 

Pollock BG, Wylie M, Stack JA, Sorisio DA, Thompson DS, Kirshner MA, Folan MM, Con-difer KA. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol (1999) 39, 936 0. 

Uncertain. Estrogens can inhibit the cytochrome P450 isoenzyme CYP1A2, by which caffeine is metabolised, which may explain its accumulation in the body. 

An established interaction that is probably of limited clinical importance. Women taking oral contraceptives containing estrogens or HRT who take caffeine-containing analgesics or drink caffeine-containing drinks (tea, coffee, cola drinks, etc.) may find the effects of caffeine, such as jitteriness and insomnia, increased and prolonged. 

In 1957 Carol published a short review on the application of infrared methods to pharmaceutical analysis. Among the substances for which infrared methods had been developed at that time he mentioned atropine, nitroglycerine, sodium A-lauroyl sarcosinate, phenobarbital, testosterone, and progesterone. Other substances for which analytical methods were given were penicillin G in the presence of penicillin F, K, or dihydro-F ethinyl testosterone aspirin, phenacetin, and caffeine and estrogenic substances, e.g., estrone, equilin, and estradiol-17-/J (cis). 

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