ORAL CONTRACEPTIVEs

These are drugs taken orally to prevent conception. They are available in the following forms:

1. Combined regimen type
2. sequential regimen type
3. triphasic pill regimen

Combined regimen: involves the administration of pills containing combination of Estrogen and Progestogen. They are administered starting 5^th day of menustral cycle for 21 days.

They can also be classified as fixed dose combination (monophasic), biphasic and triphasic pills. Fixed dose combination: the commonest procedure is to administer one pill containing both an estrogen and progestin daily at bed time for 21 days. In biphasic and triphasic pills: these are combined oral contraceptive pills containing varying proportion of an estrogen and a progesterone designed to stimulate the normal pattern of menustral cycle.

Formulation:

1. low estrogen, low progesterone(0.03mg ethinylestradiol+0.15 mg norgestril
2. Low esterogen, high progestogen (0.03 mg ethinylestradiol + 1.5 mg norethindrone)
3. High estrogen, high progestrone (0.05 mg ethinylestradiol + 0.5 mg norgestril)

Mechanism: includes inhibition of release of FSH and LH, increase viscosity of cervical mucus endometrial changes, interfere with contraction of cervix, uterus and fallopian tube.