Levonorgestrel
Mechanism :
Levonorgestrel is a totally synthetic and biologically active progestin that exhibits no significant estrogenic activity. At least two mechanisms of action are known, ovulation inhibition and thickening of the cervical mucus.
Indication :
Contraindications :
Contraindicated in active thrombophlebitis or thromboembolic disorders, undiagnosed abnormal genital bleeding, acute liver disease, benign or malignant liver tumors, known or suspected carcinoma of the breast, history of idiopathic intracranial hypertension, hypersensitivity to levonorgestrel or any of the components of the implants.
Dosing :
1.5 mg orally 1 tablet. Start as soon as possible after unprotected intercourse; maximum efficacy within 72 hours, moderate efficacy within 120 hours.
Adverse Effect :
Commonly seen adverse reactions are breast tenderness headache, skin disorders, weight gain, nausea, ovarian cysts, vaginal bleeding, vulvovaginitis.
Interaction :
Phenytoin, Phenobarbital, Carbamazepine or Oxcarbazepine: Levonorgestrel is less effective in patients taking these drugs.
Rifampicin: Known to decrease the effectiveness.
Hepatic Dose :
Avoid use of the levonorgestrel intrauterine systems for routine contraception if significant hepatic disease is present. For emergency contraception, use with caution.