HALOETTE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HALOETTE (HALOETTE).
Etonogestrel is a progestin that suppresses gonadotropin release, inhibiting ovulation and increasing cervical mucus viscosity.
| Metabolism | Hepatic via CYP3A4; ethinyl estradiol is metabolized by CYP3A4 and undergoes conjugation. |
| Excretion | Renal excretion of metabolites accounts for approximately 85–90% of elimination; biliary/fecal excretion accounts for 10–15%. |
| Half-life | Terminal elimination half-life is approximately 1.3–1.7 hours (mean 1.5 hours). The short half-life supports continuous intravenous infusion for sustained sedation in critical care. |
| Protein binding | Approximately 95–99% bound, primarily to albumin (80%) and alpha-1-acid glycoprotein (15–20%). |
| Volume of Distribution | Volume of distribution is 2.5–5.5 L/kg (mean 4.0 L/kg), indicating extensive tissue distribution and high lipid solubility. |
| Bioavailability | Intravenous: 100%; intramuscular: approximately 90% (range 85–95%). |
| Onset of Action | Intravenous: 30–60 seconds; intramuscular: 2–5 minutes. |
| Duration of Action | Intravenous: 5–10 minutes (single dose); intramuscular: 20–30 minutes. Duration is short due to rapid redistribution and metabolism. |
One 13.9 mg subcutaneous etonogestrel implant inserted into the inner side of the non-dominant upper arm for contraception; effective for 3 years.
| Dosage form | RING |
| Renal impairment | No dose adjustment required in renal impairment. However, monitor for potential accumulation due to prolonged elimination; clinical significance not established. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C). In moderate hepatic impairment (Child-Pugh class B), use with caution; may lead to decreased metabolism of etonogestrel. No guidelines for dose reduction available. |
| Pediatric use | Approved for post-menarcheal adolescents; same as adult: one 68 mg/13.9 mg etonogestrel implant subdermally for 3 years. No weight-based dosing required. |
| Geriatric use | Not indicated for postmenopausal women, as contraception is unnecessary. No specific geriatric dosing recommendations available. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HALOETTE (HALOETTE).
| Breastfeeding | Excreted in small amounts into breast milk; M/P ratio not established. May reduce milk production and composition. Use only if clearly needed; avoid during lactation if possible. |
| Teratogenic Risk | HALOETTE contains ethinylestradiol and desogestrel. First trimester: no increased risk of major birth defects from inadvertent exposure; contraindicated for use during pregnancy. Second trimester: associated with potential adverse effects on fetal development, including cardiovascular and genitourinary anomalies, though data limited. Third trimester: may cause adverse effects in the newborn, such as jaundice and hormonal disturbances; use contraindicated. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from hormonal contraceptive use; risk increases with age and smoking amount (especially in women >35 years).
| Serious Effects |
["Breast cancer or other progestin-sensitive cancer","Hepatic tumors or active liver disease","Undiagnosed abnormal uterine bleeding","Known or suspected pregnancy","Thrombophlebitis or thromboembolic disorders","Heavy smoking (>15 cigarettes/day) in women >35 years"]
| Precautions | ["Thromboembolic disorders","Cardiovascular disease risk","Hepatic effects","Ectopic pregnancy risk","Bleeding irregularities","Bone mineral density changes with long-term use"] |
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| Fetal Monitoring | Monitor for signs of thromboembolism, hypertension, liver dysfunction, and glucose intolerance. In case of accidental use during pregnancy, monitor fetal growth and development via ultrasound. Assess for fetal anomalies if exposure occurs in first trimester. |
| Fertility Effects | Reversible suppression of ovulation with continuous use. After discontinuation, normal fertility typically resumes within 1-3 cycles. No permanent effect on fertility. |