(eth' in il) (es tra dye' ol)
P : Contraindicated in pregnancy
L : Contraindicated in lactation
|| See TERMINOLOGY & ABBREVIATIONS ||
|Indication & Dosage||Menopausal hormone replacement therapy
Adult: In menopausal women: 10-20 mcg daily in conjunction with a progestogen in women with uterus.
Adult: 10-50 mcg daily in a cyclical regimen.
Palliative treatment of breast carcinoma
Adult: In postmenopausal women: 0.1-1 mg tid.
Palliative treatment of prostatic carcinoma
Adult: 0.15-3 mg daily.
As part of combined oral contraceptive
Adult: As the oestrogenic component of combined oral contraceptive: 20-40 mcg/day.
|Administration||May be taken with
or without food.
|Contraindications||Uterine, liver and mammary carcinoma, thromboembolic disorders. Pregnancy, lactation, untreated endometriosis, jaundice, undiagnosed vag bleeding.|
|Special Precautions||Asthma; epilepsy; migraine; DM; cardiac or renal dysfunction; hepatic disease; familial defects of lipoprotein metabolism. Increased risk of endometrial cancer in unopposed oestrogen therapy. Increased risk of gallbladder disease in women on postmenopausal oestrogens. Large doses may increase CV risk, BP, risk of thrombophlebitis and pulmonary embolism.|
|Adverse Drug Reactions||Oedema, hypertension; dizziness; headache; thromboembolism; cholestatic jaundice; nausea,
vomiting; disturbance of menstrual cycle; fluid retention, discomfort in breast, wt gain/loss; increased appetite, increased tendency for vag candidiasis;
mental depression; alteration in libido; rashes; alopoecia, hirsutism; gynaecomastia and impotence.
Potentially Fatal: Endometrial cancer (prolonged use).
|Drug Interactions||CYP1A2 and CYP3A4 inducers such as aminoglutethimide, carbamazepine, phenobarbital, and rifampin may decrease the effects of estradiol.
May enhance the effects of hydrocortisone and prednisolone when used together. Altered anticoagulant effect when used with dicoumarol.
Potentially Fatal: Antibiotics (ampicillin, tetracycline, sulphonamides and chloramphenicol) can cause intermenstrual bleeding or failure of contraception. Reduced efficacy of antihypertensives or hypoglycaemic drugs.
|Food Interaction||Folic acid absorption may be decreased. Black cohosh, dong quai, red clover, saw palmetto, ginseng, St John's wort.|
|Lab Interference||Reduced response to metyrapone test.|
|Pregnancy Category (FDA)||Category X: Studies in animals or human beings have demonstrated foetal abnormalities or there is evidence of foetal risk based on human experience or both, and the risk of the use of the drug in pregnant women clearly outweighs any possible benefit. The drug is contraindicated in women who are or may become pregnant.|
|Pharmacology||Oestradiol is the major oestrogen in pre-menopausal women. Ethinylestradiol has similar actions as oestradiol. It is responsible for the
development and maintenance of female reproductive system and secondary sexual characteristics. It also inhibits anterior pituitary by negative feedback
effect and causes capillary dilation, fluid retention and protein anabolism.
Absorption: Rapidly and well absorbed from the GI tract. Systemic bioavailability: About 40%.
Distribution: Highly protein bound.
Metabolism: Hepatically metabolised.
Excretion: Urine and faeces.