Levonorgestrel
Generic Details
Generic Name
Levonorgestrel
Other Names
- Plan B
- Emergency Contraceptive Pill
Drug Class
- Progestin
Chemical Formula
C21H28O2
Molecular Weight
312.45 g/mol
Mechanism of Action
- Prevents ovulation
- Thickens cervical mucus to prevent sperm from reaching the egg
- Alters the endometrium preventing implantation
Indications
- Emergency contraception
- Birth control
Common Dosage Forms
- Tablet
- Implant
Typical Dosage
- 1.5mg tablet as a single dose for emergency contraception
Pediatric Dosage
Geriatric Dosage
Side Effects
- Nausea
- Vomiting
- Fatigue
- Headache
- Irregular bleeding
Contraindications
- Known or suspected pregnancy
- Severe liver disease
Pregnancy Category
- Not for use during pregnancy
Lactation Safety
- Considered compatible with breastfeeding
Drug Interactions
- Enzyme inducers may decrease effectiveness
Overdose Symptoms
- Nausea
- Vomiting
- Menstrual irregularities
Antidote for Overdose
No specific antidote
Storage Conditions
- Store at room temperature away from moisture and heat
Pharmacokinetics
- Absorption: Rapidly absorbed
- Distribution: Protein-bound
- Metabolism: Hepatic
- Excretion: Renal
Precautions
- History of ectopic pregnancy
- History of thromboembolic disorders
Warnings
- Not for use as a regular contraceptive method
- Does not protect against sexually transmitted infections
Others
- Available over-the-counter in many countries