Basic product information

• Active ingredient: Levonorgestrel
• Type: Emergency contraceptive pill (ECP)
• Typical dose: Usually a single dose of 1.5 mg (or 2 tablets of 0.75 mg, depending on brand)
• Use: After unprotected sex or contraceptive failure (not ongoing birth control)

Brand names and tablet strengths may vary by pharmacy and stock. Always check the product label for the exact instructions supplied with your pack.

How Plan B works (mechanism of action)

Levonorgestrel is a synthetic progestogen. Plan B primarily works by delaying ovulation (the release of an egg) if taken before ovulation occurs.

• Delays or inhibits ovulation: If you take it in the pre-ovulatory window, it can reduce the likelihood of fertilisation.
• May affect sperm/egg transport: Levonorgestrel can also influence the conditions in the reproductive tract in a way that may reduce the chances of fertilisation.
• Does not reliably affect implantation: It is not designed to disrupt an established pregnancy.

Plan B is most effective when taken as early as possible after unprotected sex. Effectiveness tends to decline as time passes.

Pharmacokinetics (how the body processes levonorgestrel)

After taking the pill by mouth, levonorgestrel is absorbed and reaches peak levels in the bloodstream within a few hours. It is metabolised mainly in the liver and is eliminated through urine and bile/faecal routes.

• Absorption: Rapid oral absorption; peak blood concentration typically occurs within hours.
• Distribution: Binds to transport proteins in blood.
• Metabolism: Primarily hepatic metabolism.
• Elimination: Excreted as metabolites; the active effect for emergency contraception depends largely on timing relative to ovulation.

Because emergency contraception effectiveness depends on whether ovulation has already occurred, the “pharmacokinetic” timing matters less than the clock: take it promptly.

Typical use and when to take it

Plan B is used to reduce the risk of pregnancy after:

• Unprotected intercourse (no contraception)
• Contraceptive failure (e.g., condom broke, slipped, or was used incorrectly)
• Missed or late contraceptive pills (when applicable to your regimen)
• Incorrect timing of certain contraceptives
• Sex after contraception was stopped or delayed

Timing: take it as soon as possible

Plan B should be taken as soon as possible after unprotected sex. It is commonly indicated for use within up to 72 hours (3 days) after sex, though some guidance and brands may extend use up to 120 hours (5 days). Efficacy generally decreases over time.

If you are beyond the 72-hour mark, consider whether an alternative emergency contraceptive may suit you better (see “Alternative options” below).

If you vomit after taking it

If you vomit within a few hours of taking the dose, you may not have absorbed the full amount. Check the product instructions; often, you may need another dose. If unsure, contact a pharmacist.

Food interactions

Plan B can generally be taken with or without food. Food is not known to significantly reduce effectiveness.

• Take it in a way you can remember: Many people prefer taking it with a snack or meal to reduce nausea.
• If you have a sensitive stomach: Ginger tea, water, or an anti-nausea approach may help—ask a pharmacist for advice.

Alcohol and medicine interactions

Alcohol

Alcohol does not directly “cancel” levonorgestrel. However, heavy alcohol use can increase the likelihood of vomiting or forgetting whether you have taken the dose. If you choose to drink, keep it moderate and ensure you take the pill correctly.

Other medicines (important interactions)

Some medicines can reduce the effectiveness of levonorgestrel by increasing liver metabolism. This includes certain drugs that induce hepatic enzymes.

Examples of medicine classes that may interact include (not exhaustive):

• Some anti-seizure medicines (e.g., carbamazepine, phenytoin, phenobarbital, topiramate at higher doses)
• Rifampicin and some antibiotics used for tuberculosis
• Some HIV medications (enzyme inducers)
• St John’s wort (herbal supplement)
• Certain long-term hormone-modulating treatments

If you take any regular medicines or supplements, it’s wise to discuss with a pharmacist to confirm the best emergency contraception option for your situation.

Note on ongoing contraception: Plan B does not replace regular contraception. Continue or restart your usual method as advised.

Indications (who Plan B is for)

Plan B is indicated for emergency contraception after unprotected sex or contraception failure. It is for use by individuals who can become pregnant and who want to lower the risk of pregnancy from that specific episode.

It is also suitable for use regardless of age once available from the pharmacy supply, following the product’s instructions and any national pharmacy guidance in Australia.

Dosing (how to take Plan B)

The standard emergency dose of levonorgestrel is typically 1.5 mg total taken as a single dose. Some packs use two tablets of 0.75 mg taken together.

Starting regular contraception after Plan B

If you use hormonal contraception, ask a pharmacist about whether to continue it immediately or use backup (e.g., condoms) for a short period. In many cases, you can continue your method, but backup is commonly recommended until you are adequately protected again.

Plan B works for the recent exposure; it does not provide ongoing protection for future sex acts.

What to expect after taking Plan B

• Menstrual changes: Your next period may come earlier or later than expected, or be lighter/heavier.
• Nausea and dizziness: These can occur, usually mild and temporary.
• Headache, breast tenderness: Some people experience temporary hormonal side effects.
• Lower abdominal cramps: Possible but should not be severe.

If you experience severe pain, heavy bleeding, or symptoms that worry you, seek medical advice promptly.

Safety profile (tolerability and who should be cautious)

Levonorgestrel emergency contraception has a long history of use and is generally well tolerated. Most side effects are temporary.

Common side effects

• Nausea
• Fatigue
• Headache
• Lower abdominal pain or cramps
• Dizziness
• Breast tenderness
• Changes to menstrual bleeding patterns

Serious warning signs

Although uncommon, get urgent medical help if you have:

• Severe abdominal pain (especially one-sided) with or without fainting
• Very heavy bleeding (soaking through pads rapidly)
• Symptoms of allergy such as swelling of lips/face, trouble breathing, or widespread rash

Pregnancy considerations

Plan B is not intended to cause harm to an existing pregnancy. If you become pregnant, you should seek medical care. If your period is more than a week late, or if you have unusual bleeding, take a pregnancy test.

Breastfeeding

Levonorgestrel is generally considered compatible with breastfeeding, but if you are breastfeeding, a pharmacist can provide guidance on timing and reassurance based on the product you receive.

Adolescents

Emergency contraception can be used by adolescents as appropriate. A pharmacist can provide supportive information about side effects and follow-up.

Practical use tips (getting the best outcome)

• Don’t wait for symptoms: Take Plan B as soon as possible after unprotected sex.
• Plan ahead: Keep a reminder on your phone or store the emergency medicine location for quick access.
• Check timing window: If you are near or beyond 72 hours, ask a pharmacist about the most suitable option.
• Use backup contraception: After taking Plan B, use condoms or avoid unprotected sex until your regular method is reliable.
• Track your period: If your period is more than 7 days late, take a pregnancy test.
• Know when to test: Pregnancy tests are most reliable from the time of a missed period, or about 3 weeks after the unprotected sex if unsure.

If you had more than one episode

If multiple episodes of unprotected sex occurred in the same cycle, emergency contraception may be relevant for each exposure, but timing and effectiveness vary. If you are unsure, ask a pharmacist for tailored advice.

Alternative options for emergency contraception

Depending on timing, body weight, and medicine interactions, other emergency contraception options may be considered. The most appropriate choice can vary from person to person.

Ulipristal acetate (ER contraception pill)

• Often used up to 120 hours (5 days) after unprotected sex.
• May be more effective than levonorgestrel closer to ovulation for some individuals.

Copper intrauterine device (Cu-IUD)

• Highly effective and can be inserted by a clinician.
• May also provide ongoing contraception afterward if desired.

When to consider alternatives

• If you are beyond 72 hours and want the best possible effectiveness.
• If you take enzyme-inducing medicines or supplements that may reduce levonorgestrel effectiveness.
• If you have concerns about timing relative to ovulation.

A pharmacist can help you weigh options based on how long ago the unprotected sex occurred and your circumstances.

Market and legal context for Australia

In Australia, emergency contraception is available through pharmacies. Access pathways can differ depending on the product and the circumstances, including age and local service protocols.

• Pharmacy supply: Many emergency contraception products may be obtained from a pharmacy setting.
• Privacy: Pharmacies generally support discreet counselling and purchase.
• Clinical guidance: Health professionals use national and clinical guidance to advise on timing, interactions, and follow-up.

This page aims to provide general information to support safe decision-making and correct use. Always refer to the pack instructions and seek professional advice if you have questions.

Recent guidance and updates (what matters most)

Guidance in Australia and internationally consistently emphasises:

• Take it as soon as possible: Earlier use generally improves effectiveness.
• Consider other options if timing is later: If you are near or after 72 hours, ask about the most effective method available to you.
• Be mindful of interactions: Enzyme-inducing medicines and herbal supplements can reduce effectiveness.
• Follow-up testing: Take a pregnancy test if your period is late or if you have ongoing symptoms.

Specific recommendations can depend on product availability and patient factors. A pharmacist can confirm the best approach for your situation.

Delivery and availability

Online pharmacy ordering may make emergency contraception more accessible, especially outside business hours. Delivery options can vary by state/region and by the courier service available at the time of order.

• Availability: Stock levels can change, particularly for emergency contraception products.
• Dispatch times: Many online pharmacies dispatch promptly after the order is confirmed.
• Delivery timing: Estimated delivery times are typically shown at checkout.
• Packaging: Products are usually shipped in discreet packaging where possible.

If you need it urgently, choose the fastest available delivery option. Also check the product label for the correct timing window.

FAQ about Plan B (levonorgestrel) in Australia

1) Is Plan B the same as the morning-after pill?

Yes. Plan B is one brand of an emergency contraception pill containing levonorgestrel. Emergency contraception is sometimes called the “morning-after pill,” though it can be taken later than the morning.

2) How effective is Plan B?

Effectiveness is highest when taken as soon as possible. It reduces the chance of pregnancy, but no emergency contraception method is 100% effective. If you are beyond the recommended timing window or have risk factors such as certain drug interactions, consider speaking to a pharmacist about alternatives.

3) Can I take Plan B more than once?

You can take emergency contraception more than once if needed, but it is not intended for repeated use as ongoing contraception. Frequent use may cause menstrual disruption. If you find yourself needing it often, consider talking to a healthcare professional about longer-term, more reliable contraception.

4) Will Plan B stop a pregnancy that has already started?

Plan B is designed to prevent or delay ovulation. It is not an abortion method and is not intended to end an established pregnancy. If pregnancy occurs, medical advice is recommended.

5) When should I do a pregnancy test?

If your period is more than 7 days late, take a pregnancy test. Alternatively, you can test around 3 weeks after the unprotected sex for more reliable results.

6) What if I’m not sure when ovulation is?

Ovulation timing can be difficult to predict. Because emergency contraception works best before ovulation, it’s generally recommended to take Plan B as soon as possible. If there are concerns about timing, drug interactions, or longer time since exposure, ask a pharmacist about the most effective available option.

7) Does Plan B affect my next period?

Yes, Plan B can change your next period. It may arrive early or late, or be lighter or heavier. If it’s significantly late or you have unusual symptoms, take a pregnancy test or consult a clinician.

8) Can I take Plan B with my regular medication?

Many medicines can be taken alongside levonorgestrel without issue, but some can reduce effectiveness. If you take enzyme-inducing medicines (such as certain anti-seizure medicines or rifampicin) or herbal products like St John’s wort, ask a pharmacist for guidance.

9) Can I breastfeed after taking Plan B?

Levonorgestrel emergency contraception is generally considered compatible with breastfeeding. If you have concerns, speak to a pharmacist for advice based on your situation.

10) Does Plan B protect me if I have sex again?

No. Plan B only addresses the risk from the unprotected sex episode around the time you take it. Use reliable contraception (e.g., condoms) for future sex until you are protected again.

When to seek medical advice

Consider contacting a clinician or pharmacy urgently if you experience:

• Severe or worsening abdominal pain
• Very heavy bleeding
• Fainting, signs of an allergic reaction, or trouble breathing
• Your period is more than 7 days late or you have a positive pregnancy test
• You have repeated episodes of unprotected sex and want a plan for ongoing prevention

Pharmacists can provide guidance about timing, side effects, and interactions and can help you decide whether an alternative emergency contraception option is more suitable.