Levonorgestrel

# levonorgestrel ## Overview - **Classification**: Progestin, Contraceptive - **Mechanism**: Primarily prevents ovulation, thickens cervical mucus, and thins the endometrial lining, inhibiting sperm passage and implantation. ## Primary Indications 1. **Emergency Contraception (EC)**: Reduces risk of pregnancy after unprotected intercourse. 2. **Long-Acting Reversible Contraception (LARC)**: As a progestin-releasing intrauterine device (IUD). 3. **Heavy Menstrual Bleeding (HMB)**: As a progestin-releasing IUD. ## Adult Dosing ### Standard Dosing **Emergency Contraception (Plan B One-Step® or generic equivalent)** - **Dose**: **1.5 mg** (single dose) - **Frequency**: Once - **Route**: Oral - **Duration**: Taken within **72 hours** of unprotected intercourse, ideally sooner. May be effective up to 120 hours. **Long-Acting Reversible Contraception / Heavy Menstrual Bleeding (IUD)** - **Dose**: Hormonal IUDs (e.g., Mirena, Kyleena, Skyla, Liletta) contain **13.5 mg** to **52 mg** total, releasing varying microgram/day amounts. - **Frequency**: Single insertion for years of contraception. - **Route**: Intrauterine insertion - **Duration**: **3 to 8 years**, depending on the specific device. ### Dose Adjustments - **Renal Impairment**: No specific adjustment needed. - **Hepatic Impairment**: Use with caution. Not recommended for severe hepatic impairment or acute liver disease. - **Elderly Patients**: Not indicated for post-menopausal women. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: Not indicated. - **Special Notes**: Levonorgestrel contraception is not applicable in this age group. ### Infants (1-12 months) - **Dose**: Not indicated. - **Special Notes**: Levonorgestrel contraception is not applicable in this age group. ### Children (1-12 years) - **Dose**: Not indicated for contraception. - **Special Notes**: Levonorgestrel contraception (EC or IUD) is typically for post-menarcheal individuals. ### Adolescents (13-18 years) **Emergency Contraception** - **Dose**: **1.5 mg** (single dose) - **Frequency**: Once - **Maximum**: **1.5 mg** total dose - **Special Notes**: Dosing is the same as adults. Counseling on contraception and STIs is crucial. **Long-Acting Reversible Contraception (IUD)** - **Dose**: Adult IUD devices (e.g., Mirena, Kyleena, Skyla) are used. - **Maximum**: Refer to specific device for total levonorgestrel content. - **Special Notes**: May be used in nulliparous and adolescent individuals post-menarche. ## Safety Information ### Contraindications - **Absolute**: Known or suspected pregnancy, undiagnosed abnormal uterine bleeding. - **Absolute (IUD)**: Pelvic inflammatory disease (current/recurrent), postpartum endometritis/septic abortion (last 3 months), cervical/endometrial cancer, uterine anomalies. - **Absolute (Hormonal)**: Known or suspected breast cancer or other progestin-sensitive cancer, acute liver disease/tumor. ### Common Adverse Effects - **Emergency Contraception**: Nausea, abdominal pain, fatigue, headache, dizziness, menstrual changes (early/late period, spotting). - **IUD**: Altered bleeding patterns (spotting, irregular bleeding, amenorrhea), headache, abdominal/pelvic pain, ovarian cysts, acne, breast tenderness. ### Key Drug Interactions - **CYP3A4 Inducers (e.g., rifampin, phenytoin, carbamazepine, St. John's Wort)**: Decrease levonorgestrel levels, reducing contraceptive efficacy. - **Protease Inhibitors (e.g., ritonavir, efavirenz)**: May decrease levonorgestrel levels. Consider higher EC dose or non-hormonal EC. ## Monitoring & Follow-up - **Before Treatment (EC)**: Pregnancy test if indicated, assess timing of unprotected sex. - **Before Treatment (IUD)**: Pelvic exam, pregnancy test, STI screening, Pap test (if due), uterine sounding. - **During Treatment (EC)**: Counsel to seek medical attention if period is delayed >1 week or severe abdominal pain. - **During Treatment (IUD)**: Follow-up 4-6 weeks post-insertion, then annually. Monitor for changes in string length. - **Clinical Signs**: Persistent severe abdominal pain (rule out ectopic pregnancy, perforation), signs of infection (fever, discharge), missing strings, pregnancy symptoms. ## Clinical Pearls - 💡 **EC Efficacy**: Most effective when taken as soon as possible after unprotected sex. It is NOT an abortifacient. - 💡 **EC Repeated Use**: Not intended for routine contraception; less effective than continuous methods. - 💡 **IUD Counseling**: Inform patients about potential for irregular bleeding, especially in the first few months, and amenorrhea. - 💡 **IUD Strings**: Teach patients how to check IUD strings regularly to ensure proper placement. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.