PREVIFEM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PREVIFEM (PREVIFEM).
PREVIFEM is a combination of ethinyl estradiol, an estrogen, and norgestimate, a progestin. It inhibits ovulation by suppressing gonadotropin release from the pituitary (FSH and LH). Additionally, it increases viscosity of cervical mucus, impeding sperm penetration, and alters the endometrium.
| Metabolism | Ethinyl estradiol is primarily metabolized by CYP3A4, with conjugation to glucuronide and sulfate. Norgestimate is rapidly metabolized to norelgestromin and levonorgestrel, primarily by CYP3A4 and other CYP enzymes. |
| Excretion | Renal (60% as metabolites, <10% unchanged), fecal (30%), biliary (10%) |
| Half-life | 20-24 hours; steady-state reached in 5 days |
| Protein binding | 97-99% bound to albumin; ethinyl estradiol binds to SHBG |
| Volume of Distribution | 2.8-3.7 L/kg; extensive distribution to tissues |
| Bioavailability | Oral: 55-65% (ethinyl estradiol); undergoes first-pass metabolism |
| Onset of Action | Oral: 0.5-2 hours for peak plasma concentration; contraceptive effect after 7 days of continuous use |
| Duration of Action | 24 hours; requires daily dosing for continuous contraceptive effect; withdrawal bleed within 2-3 days after last active pill |
One tablet (0.075 mg norgestrel and 0.03 mg ethinyl estradiol) orally once daily at the same time each day for 21 consecutive days, followed by 7 placebo tablets.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not recommended for use in patients with severe renal impairment or end-stage renal disease due to lack of safety data. |
| Liver impairment | Contraindicated in patients with active liver disease such as acute viral hepatitis or severe cirrhosis (Child-Pugh class C). For mild hepatic impairment (Child-Pugh A), use with caution; no specific dose adjustment established. |
| Pediatric use | Not indicated for use before menarche. For adolescent females, same dosing as adults if post-menarcheal and weight ≥35 kg, with careful monitoring. |
| Geriatric use | Not indicated for use in postmenopausal women. No specific geriatric dosing studies; consider increased risk of thromboembolic events in women >35 years who smoke or have other risk factors. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PREVIFEM (PREVIFEM).
| Breastfeeding | Small amounts excreted in breast milk; may reduce milk production. M/P ratio not established. Use caution; alternative contraception recommended for lactating women. |
| Teratogenic Risk | PREVIFEM (levonorgestrel/ethinyl estradiol) is contraindicated in pregnancy. No increased risk of birth defects in inadvertent early pregnancy; no data on second or third trimester use due to contraindication. |
| Fetal Monitoring |
■ FDA Black Box Warning
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with heavy smoking (15 or more cigarettes per day) and is quite marked in women over 35 years of age. Women who use combination hormonal contraceptives should be strongly advised not to smoke.
| Serious Effects |
["Known or suspected pregnancy.","Current or history of breast cancer.","Hepatic adenoma or carcinoma.","Undiagnosed abnormal uterine bleeding.","Current or history of thromboembolic disorders (e.g., DVT, PE).","Cerebrovascular or coronary artery disease.","Active liver disease or impaired liver function.","Uncontrolled hypertension.","Diabetes with vascular involvement.","Migraine with focal aura (if over 35 years old).","Major surgery with prolonged immobilization.","Hypersensitivity to any component."]
| Precautions | ["Increased risk of thromboembolic events including venous thromboembolism (VTE), myocardial infarction, and stroke, especially in smokers and women over 35.","Risk of hepatic neoplasia (benign and malignant).","Elevated blood pressure.","Gallbladder disease.","Carbohydrate and lipid metabolism effects.","Hereditary angioedema exacerbation.","Chloasma may occur.","Retinal vascular thrombosis."] |
Loading safety data…
| No routine monitoring required in non-pregnant patients. Pregnancy test if pregnancy suspected. Blood pressure monitoring recommended due to potential hypertensive effects. |
| Fertility Effects | Reversible suppression of ovulation. Fertility returns upon discontinuation. No permanent adverse effects on fertility. |