Levonelle One Step (Levonorgestrel)

Levonorgestrel is used as an emergency contraceptive to prevent pregnancy after unprotected sexual intercourse.

• Unprotected intercourse: reduces the risk of pregnancy when administered promptly after the event.
• Contraceptive failure: offers a backup method following missed hormonal dose or condom break.
• Delayed ovulation: inhibits or delays ovulation to prevent fertilization.
• Prevention of implantation: may alter the endometrial lining to reduce the chance of implantation.
• Post‑coital contraception: provides an effective option within 72 hours after intercourse.

• Levonorgestrel binds to progesterone receptors in the hypothalamic‑pituitary‑ovarian axis, suppressing the luteinizing hormone surge and thereby inhibiting or delaying ovulation. It may also alter tubal motility and the endometrial lining, reducing the likelihood of fertilization and implantation. These actions occur without significant systemic estrogen exposure, making the effect rapid and transient. The drug’s high affinity for the progesterone receptor ensures effective suppression of the ovulatory process within hours of ingestion.

Levonorgestrel may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Nausea: mild stomach upset that usually resolves without treatment.
• Headache: transient headache that may be relieved with over‑the‑counter analgesics.
• Fatigue: temporary feeling of tiredness or low energy.
• Abdominal pain: mild cramps or discomfort in the lower abdomen.
• Menstrual changes: spotting, earlier or later onset of the next period.

Serious or Rare Side Effects

• Allergic reaction: rash, itching, swelling of face or throat requiring medical attention.
• Severe abdominal pain or persistent vomiting: may indicate a more serious condition and should be evaluated.
• Unusual vaginal bleeding: heavy or prolonged bleeding that is not typical for the menstrual cycle.

When using Levonelle One Step, certain precautions help ensure safety and effectiveness.

• Timing of administration: take as soon as possible after unprotected intercourse, preferably within 72 hours.
• Contraindications: avoid if you have a known hypersensitivity to levonorgestrel or any tablet excipients.
• Pregnancy status: not intended for use if you are already pregnant; a pregnancy test is not required before taking the tablet.
• Breastfeeding: consult a healthcare professional, as limited data are available on exposure through breast milk.
• Drug interactions: review concomitant medications that may reduce levonorgestrel efficacy, such as certain antibiotics or anticonvulsants.
• Store at ambient temperature: keep below 25 °C, retain in the original packaging, and protect from moisture.

Levonelle One Step may interact with other medicines, affecting its effectiveness or safety.

Major Interactions (Avoid)

• Rifampicin and other enzyme‑inducing antibiotics: these agents can markedly lower levonorgestrel plasma concentrations, reducing contraceptive efficacy.
• Antiepileptic drugs (phenytoin, carbamazepine, phenobarbital): enzyme induction by these medicines may diminish the effectiveness of emergency contraception.
• St. John’s wort: this herbal supplement induces hepatic enzymes and can decrease levonorgestrel activity.

Moderate Interactions (Monitor Closely)

• Hormonal contraceptives taken concurrently: combined use may lead to reduced overall contraceptive protection, so additional precautions are advised.
• Antifungal azoles (ketoconazole, itraconazole): these can increase levonorgestrel levels, potentially heightening side‑effect risk.
• Antiretroviral efavirenz: may lower levonorgestrel effectiveness, requiring consideration of alternative emergency contraception.