Levonorgestrel Emergency Pill

Levonorgestrel emergency contraceptive pills are a progestin-only oral method taken after unprotected intercourse. The dose is 1.5 mg as a single dose, as soon as possible and within 120 hours. They prevent up to 95% of expected pregnancies, with the highest effect when taken early. They are available in public, private and nongovernmental facilities and over the counter at pharmacies.

Formulations. One 1.5 mg tablet, or two 750 microgram tablets given together. Regular progestin-only pills are weaker and are not a substitute.

Mechanism. Levonorgestrel delays or inhibits ovulation and may slow ovum transport. It is effective only when taken before the luteinising hormone surge begins. It does not end an established pregnancy.

Pharmacokinetics. Absorption is rapid, with peak levels within about 2 hours. The half-life is about 24 hours. Metabolism is hepatic, so enzyme inducers lower exposure.

Effectiveness. About 8 pregnancies in 100 women follow one act of unprotected intercourse in the fertile phase. After levonorgestrel, 1 to 2 in 100 women become pregnant. Efficacy falls as the interval lengthens and as body weight rises.

Duration and return to fertility. The dose covers the episode treated. Fertility returns at once, and ovulation may occur later in the same cycle.

Levonorgestrel suits any patient at risk of pregnancy, including adolescents and those who cannot use ongoing hormonal methods. No examination, pregnancy test or laboratory test is needed for one recent episode.

Category 1. Breastfeeding, previous ectopic pregnancy, sexual assault, obesity, and enzyme inducers (rifampicin, rifabutin, phenytoin, phenobarbital, carbamazepine, efavirenz, nevirapine).

Category 2. Previous ischaemic heart disease, stroke or other thromboembolic disease, angina, migraine, and severe liver disease including jaundice. Give without delay.

Not indicated. Known pregnancy. Accidental use causes no known harm.

Interactions. Enzyme inducers, including St John's wort and griseofulvin, lower levonorgestrel levels. At higher body weight the effect is also lower. In both situations the copper IUD is more reliable, and ulipristal acetate is a further option. If neither can be given, a single dose of 3 mg (two 1.5 mg tablets together) is used, although evidence for this dose is limited.

Do not combine. Levonorgestrel and ulipristal acetate are not given together for the same episode, because a progestin reduces the effect of ulipristal acetate.

Counselling points for the clinician. Obtain consent, protect confidentiality and exclude coercion. Under 18 years give assent, with consent in line with the law. State plainly that the dose does not protect against sexually transmitted infections or HIV and does not protect for the rest of the cycle. Advise against use as a regular method.

Special groups.

• Breastfeeding: levonorgestrel is the oral option of choice.

• Postpartum: not needed before 4 weeks after birth.

• Postabortion: ovulation can return within 2 weeks, so the dose is appropriate after unprotected intercourse.

• Adolescents: no age limit applies.

Regimen.

• Drug and strength: levonorgestrel 1.5 mg total. Route: by mouth.

• Preferred: two 750 microgram tablets together as one dose. Alternative: one 750 microgram tablet, then a second 750 microgram tablet 12 hours later.

• Timing: as soon as possible, within 120 hours of unprotected intercourse.

• Frequency: one course for each episode. There is no grace window beyond 120 hours.

• Duration of protection: the episode treated only.

• Backup: condoms until menses, or until the next method takes effect.

Pregnancy exclusion. Pregnancy is reasonably excluded when there has been no unprotected intercourse since the last normal menses and menses are not overdue. A test is not required before one recent episode. If menses are more than 7 days late, test.

Vomiting. Within 2 hours of the dose, repeat it with an antiemetic. If vomiting continues, place the repeat tablets high in the vagina. After more than 2 hours, give nothing further.

Starting ongoing contraception after levonorgestrel.

• Combined and progestin-only pills: start the day after the dose, without waiting for menses. Backup 7 days for combined pills and 2 days for progestin-only pills.

• Injectable: same day with 7 days of backup, or within 7 days of the start of menses with no backup.

• Copper IUD: same day, no backup needed.

• Implant: within the first 7 days of the next menses, with condoms or pills until then.

• Condoms: start immediately.

Follow up. No routine visit is needed. Advise return for menses more than 7 days late, unusual bleeding or lower abdominal pain. Test 3 weeks after the episode if menses have not started.

Expected effects. Nausea, abdominal pain, fatigue, headache, dizziness and breast tenderness are common and short-lived. Menses may come earlier or later by a few days. Irregular spotting before the next menses is common.

Management.

• Mild nausea: reassure and advise food or milk.

• Severe nausea: ondansetron 4 mg by mouth as one dose, repeated once after 8 hours if needed. Maximum 12 mg in 24 hours, for no more than 2 days. Limit to 8 mg in 24 hours in severe liver disease. No kidney adjustment is needed. Avoid in congenital long QT syndrome. In pregnancy use only when the benefit is clear. Short courses are acceptable in breastfeeding.

• Headache: a mild analgesic if blood pressure is normal. Refer if blood pressure is high.

• Spotting: reassure if not pregnant and help the patient choose a regular method.

Failure and pregnancy. A pregnancy after the dose is not harmed by it. Assess for ectopic pregnancy when a positive test comes with pain or bleeding.

Repeated use. Repeat use is safe in most patients but shows a need for a regular method. Patients in category 3 or 4 for hormonal methods are better served by the copper IUD.

Referral and escalation. Refer for severe lower abdominal pain, fainting, heavy bleeding, persistent vomiting or a positive pregnancy test with pain or bleeding.