KARIVA
Clinical safety rating
cautionComprehensive clinical and safety monograph for KARIVA (KARIVA).
Combination of ethinyl estradiol (estrogen) and levonorgestrel (progestin) that inhibits gonadotropin release, suppressing ovulation, altering cervical mucus to impede sperm penetration, and changing endometrial receptivity.
| Metabolism | Hepatic via CYP3A4 for both ethinyl estradiol and levonorgestrel; undergoes conjugation (glucuronidation and sulfation). Ethinyl estradiol also undergoes oxidative metabolism. Levonorgestrel is reduced and conjugated. |
| Excretion | Approximately 55% renal (30% as unchanged drug, 25% as metabolites) and 45% fecal (via biliary elimination). |
| Half-life | Terminal elimination half-life is 4.5 hours; in renal impairment (CrCl <30 mL/min), half-life may extend to 8-10 hours, requiring dose adjustment. |
| Protein binding | 99% bound to albumin; minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.27 L/kg (range 0.2-0.5 L/kg); distribution into total body water and highly perfused tissues. |
| Bioavailability | Oral: 85-90% (complete absorption; first-pass metabolism reduces systemic availability to ~75% in elderly). |
| Onset of Action | Oral: 30-60 minutes (analgesic effect); peak effect at 2-3 hours. |
| Duration of Action | 3-4 hours for single dose; sustained pain relief up to 6 hours when administered with food. |
| Molecular Weight | Ethinylestradiol: 296.4 Da; Levonorgestrel: 312.4 Da |
One tablet (0.15 mg levonorgestrel/0.03 mg ethinyl estradiol) orally once daily at the same time each day for 21 days, followed by 7 days of placebo.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment or end-stage renal disease; use with caution and monitor for adverse effects. |
| Liver impairment | Contraindicated in acute hepatic disease or severe hepatic impairment (Child-Pugh class B or C). For mild hepatic impairment (Child-Pugh class A), no specific dosage adjustment is established; use with caution and monitor liver function. |
| Pediatric use | Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (one tablet daily as per 21/7 regimen). |
| Geriatric use | Not indicated for use after menopause. No specific elderly considerations as the drug is not used in this population. |
| 1st trimester | Avoid pregnancy. Use effective contraception. Contraindicated in pregnancy due to teratogenicity (similar to other vitamin A derivatives). Risk of major congenital malformations. |
| 2nd trimester | Contraindicated. Avoid use during pregnancy due to continued risk of fetal harm. |
| 3rd trimester | Contraindicated. Avoid use during pregnancy due to risk of fetal harm. |
Clinical note
Comprehensive clinical and safety monograph for KARIVA (KARIVA).
| Placental transfer | Kariva (a combination of ethinylestradiol and levonorgestrel) components cross the placenta. Evidence from studies shows transfer of synthetic hormones to fetal circulation. |
| Breastfeeding | Contraindicated during breastfeeding. Excreted in breast milk; potential for serious adverse effects in nursing infant. Do not breastfeed while using Kariva. |
| Lactation Rating | L5 - Contraindicated |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy due to known teratogenicity. First trimester exposure associated with cardiovascular defects, limb reduction defects, and neural tube defects. Second and third trimester use linked to fetal hepatic adenoma and female pseudohermaphroditism (due to progestogenic activity). |
| Fetal Monitoring | Pregnancy test before initiation. Monitor for signs of pregnancy during use. If pregnancy occurs, discontinue immediately and counsel regarding fetal risks. |
| Fertility Effects | May delay return to fertility after discontinuation; long-term use does not cause permanent infertility. No evidence of increased risk of infertility following cessation. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination hormonal contraceptive use. Risk increases with age (>35 years) and with number of cigarettes smoked. Women over 35 who smoke should not use Kariva.
| Serious Effects |
PregnancyBreastfeedingHistory of thrombophlebitis or thromboembolic disordersCerebrovascular or coronary artery diseaseKnown or suspected carcinoma of the breastCarcinoma of the endometrium or other known or suspected estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingCholestatic jaundice of pregnancy or jaundice with prior pill useHepatic adenoma or carcinomaKnown hypersensitivity to any component
| Precautions | Increased risk of thromboembolic disorders (e.g., DVT, PE, MI, stroke), Hepatic neoplasia (benign and malignant) reported, Elevated blood pressure, Gallbladder disease, Carbohydrate and lipid metabolism effects, Retinal thrombosis (discontinue if vision loss or proptosis occurs), Depression, Bleeding irregularities (breakthrough bleeding, amenorrhea), Liver function abnormalities (discontinue if jaundice develops), Chloasma (may persist) |
| Food/Dietary | No specific food interactions; however, grapefruit juice may increase estrogen levels (theoretical). Avoid high-fat meals as they may affect absorption. Consistent intake with food can reduce nausea. |
| Clinical Pearls | Kariva (desogestrel/ethinyl estradiol) is a monophasic oral contraceptive. It is effective for contraception but also used for acne and menstrual regulation. Breakthrough bleeding is common in first 3 cycles. Counsel on missed pill protocol. Check for contraindications: smoking >35, history of DVT/PE, migraine with aura, liver disease, breast cancer. Note that antibiotics (rifampin, griseofulvin) and anticonvulsants may reduce efficacy. |
| Patient Advice | Take one pill daily at the same time, preferably after an evening meal. · If you miss one pill, take it as soon as remembered; if missed two or more, use backup contraception. · Common side effects include nausea, breast tenderness, and spotting; these usually improve after 3 months. · Avoid smoking while taking this medication, especially if over 35 years old. · Inform your doctor before starting any new medications, including antibiotics and herbal supplements. · Kariva may decrease milk supply; not recommended if breastfeeding. |
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