Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

History of development, composition, effectiveness, and side effects of first and second generation steroid contraceptive agents are briefly reviewed with special emphasis on advantages of third generation contraceptives, including triphasic hormonal contraceptives. Mechanism of action of triphasic contraceptives is based on the physiological biorhythm in the formation, secretion and blood levels of estrogens and gestagens during the menstrual cycle. The first phase (5 to 7 tablets) is characterized by high levels of estrogens and relatively low levels of gestagens. The second phase (5 to 10 tablets) is characterized by relatively high levels of estrogens and gestagens. And the third phase (7 to 10 tablets) is characterized by decreased levels of estrogens and significantly increased levels of gestagens. The most commonly used gestagens are levonorgestrel, norethindrone, and norethisterone. Ethinyl estradiol is the most commonly used estrogen. During various phases of the cycle the dosage of gestagens ranges from 0.03 to 1.00 mg and dosage of estrogen ranges from 0.3 to 0.4 mg. A single package of triphasic contraceptives contains 21 tablets. Duration of a cycle is 23-25 days with 7-day interval between the cycles. Hemorrhage during the first half of the cycle can be successfully treated with additional estrogens, while hemorrhage during the second half can be treated with gestagens. Side-effects of triphasic contraceptives include headache, dizziness, and irregular menstrual cycle. Triphasic contraceptives are specifically indicated to women older than 35 years of age, to smoking women, and to women with changes in lipid metabolism.
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PMID:[Triphasic hormonal contraceptives]. 267 94