PHILITH
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PHILITH (PHILITH).
PHILITH is a combined oral contraceptive containing ethinyl estradiol and drospirenone. Ethinyl estradiol suppresses gonadotropin release, while drospirenone is a progestin with antiandrogenic and antimineralocorticoid activity, inhibiting ovulation and altering cervical mucus.
| Metabolism | Ethinyl estradiol is metabolized primarily by CYP3A4, with sulfation and glucuronidation; drospirenone is metabolized by CYP3A4. |
| Excretion | Renal: 90% unchanged; biliary/fecal: 10% as metabolites. |
| Half-life | Terminal half-life 12 hours; clinically relevant for twice-daily dosing with steady state reached after 2-3 days. |
| Protein binding | 98% bound to albumin. |
| Volume of Distribution | 0.3 L/kg; suggests limited extravascular distribution. |
| Bioavailability | Oral: 80% (high first-pass metabolism). |
| Onset of Action | Oral: 30-60 minutes; Intravenous: 5-10 minutes. |
| Duration of Action | 8-12 hours; clinical effect correlates with plasma concentration. |
1 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | GFR 30-89 mL/min: no adjustment; GFR 15-29 mL/min: 0.5 mg once daily; GFR <15 mL/min: not recommended |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 0.5 mg once daily; Child-Pugh C: not recommended |
| Pediatric use | Not approved for use in children under 18 years |
| Geriatric use | No specific adjustment; monitor renal function and adjust per renal guidelines |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PHILITH (PHILITH).
| Breastfeeding | It is unknown whether PHILITH is excreted in human milk. Due to potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during therapy and for 2 weeks after last dose. M/P ratio is not available. |
| Teratogenic Risk | PHILITH is contraindicated in pregnancy. First trimester exposure carries high risk of neural tube defects, cardiac anomalies, and cleft palate based on animal studies and limited human data. Second and third trimester exposure may cause fetal growth restriction, oligohydramnios, and neonatal renal impairment. |
■ 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 oral contraceptives should be strongly advised not to smoke.
| Serious Effects |
["Pregnancy","Current or history of thrombophlebitis or venous thromboembolic disorders","Cerebrovascular or coronary artery disease","Known or suspected breast carcinoma or other estrogen-dependent neoplasia","Undiagnosed abnormal genital bleeding","Hepatic adenoma or carcinoma","Jaundice or cholestatic jaundice of pregnancy or prior pill use","Known hypersensitivity to any component","Smoking over age 35","Uncontrolled hypertension","Diabetes with vascular involvement","Migraine with focal aura","Severe renal insufficiency or adrenal insufficiency (due to drospirenone's antimineralocorticoid effect)"]
| Precautions | ["Increased risk of thromboembolic and thrombotic disorders (e.g., venous thromboembolism, stroke, myocardial infarction) especially in smokers over 35","Elevated blood pressure","Gallbladder disease","Carbohydrate and lipid metabolic effects","Hepatic neoplasia risk","Increased risk of pancreatitis due to hypertriglyceridemia","Chloasma (melasma) possibly persistent","Hereditary angioedema exacerbation in women with C1 esterase inhibitor deficiency","Impaired liver function"] |
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| Fetal Monitoring |
| Monitor maternal liver function tests, renal function, and complete blood count monthly. Perform fetal ultrasound for growth and anatomy at 18-20 weeks and growth scans every 4 weeks if exposure occurs. Monitor amniotic fluid index weekly in third trimester. |
| Fertility Effects | PHILITH may impair fertility in females by disrupting ovarian function based on animal studies. In males, reversible oligospermia or azoospermia has been reported. Contraception is recommended during treatment and for 6 months after discontinuation. |