Common use

Plan B is a widely recognized emergency contraception product containing levonorgestrel, a synthetic hormone closely related to progesterone. Levonorgestrel is the active racemic isomer of norgestrel and is approximately twice as potent in its contraceptive action. This morning after pill works through several mechanisms to provide effective pregnancy prevention. It alters the consistency of cervical mucus, making it more difficult for sperm cells to reach the uterus. It also modifies the uterine lining, which reduces the likelihood of a fertilized egg successfully implanting in the uterine wall. Additionally, levonorgestrel may suppress or delay ovulation, further reducing the chance of fertilization. When you buy Plan B online or at a pharmacy, you are obtaining a trusted emergency birth control method that has been used by millions of women worldwide. Plan B generic versions contain the same active ingredient — levonorgestrel — and offer the same level of protection. This contraceptive pill is specifically designed to prevent pregnancy when taken within 72 hours (3 days) after unprotected intercourse or when a regular contraceptive method has failed. It is important to understand that emergency contraception is not intended as a routine birth control method but serves as a critical backup option when other methods were not used or proved unreliable.



Dosage and direction

Take Plan B (levonorgestrel) orally with a glass of water. The standard regimen involves two tablets administered as follows: the first tablet should be taken as soon as possible after unprotected intercourse, ideally within the first 24 hours but no later than 72 hours. The sooner you take the first dose, the more effective this emergency contraception will be — studies show that effectiveness decreases with each passing hour. The second tablet should be taken exactly 12 hours after the first dose, and no later than 16 hours after the initial tablet. If vomiting occurs within three hours of taking either tablet, an additional replacement tablet should be taken to ensure adequate absorption of the medication. A levonorgestrel tablet of 0.75 mg may be taken on any day of your menstrual cycle, provided that your most recent period was normal and on schedule. Some single-dose formulations of this morning after pill contain 1.5 mg of levonorgestrel in one tablet, which is taken as a single dose. After using Plan B or any emergency birth control product, you should resume using your regular birth control method or use a local barrier contraceptive such as a condom for the remainder of your cycle. It is essential to follow up with a healthcare provider if your period is delayed by more than one week after the expected date.



Precautions

Repeated use of levonorgestrel as emergency contraception during the same menstrual cycle is strongly discouraged, as it may cause significant disruption to your menstrual pattern and hormonal balance. This morning after pill is not designed to replace regular, ongoing birth control and should only be used in genuine emergency situations. It is important to understand that even when taken correctly, emergency contraception may sometimes fail to prevent pregnancy — no method provides a 100% guarantee. Women who are breastfeeding should be aware that levonorgestrel is excreted into breast milk. To minimize potential effects on a nursing infant, take the tablets immediately after breastfeeding and consider avoiding breastfeeding for several hours following each dose. Before you buy levonorgestrel or any Plan B generic product, inform your doctor if you have any of the following conditions: a bleeding disorder or blood-clotting abnormality, diabetes mellitus, any active vaginal infection, a history of or current sexually transmitted disease, pelvic inflammatory disease or other pelvic infections, cardiovascular disease including heart disease or high blood pressure, or any heart valve disorder. Women over the age of 35 who smoke should exercise particular caution and discuss the risks and benefits with their healthcare provider. Additionally, body weight may influence the effectiveness of this contraceptive pill — some studies suggest reduced efficacy in women weighing over 75 kg (165 lbs), although it may still provide some level of pregnancy prevention.



Contraindications

Do not take Plan B (levonorgestrel) if you are already pregnant or suspect that you may be pregnant. This emergency contraception product will not terminate an existing pregnancy — it works only to prevent a new pregnancy from being established. The medication is contraindicated in patients with abnormal vaginal bleeding that has not been evaluated by a healthcare professional, as well as in women with an untreated or uncontrolled pelvic infection. You should not use this emergency birth control if you have experienced a serious pelvic infection following a pregnancy or abortion within the past three months. Other contraindications include uterine fibroid tumors of significant size, a history of pelvic inflammatory disease (PID) — particularly in women who have not had children — and past or present breast cancer or any estrogen- or progesterone-dependent malignancy. Women with active liver disease, liver tumors (whether benign or malignant), cervical cancer, or uterine cancer should not use levonorgestrel for emergency contraception. A recent abnormal Pap smear that has not been further evaluated is also a contraindication. Patients with significantly decreased immune function due to conditions such as leukemia, HIV/AIDS, or immunosuppression from IV drug use should consult their physician before considering this contraceptive pill. If any of these conditions apply to you, speak with your doctor about alternative pregnancy prevention options.



Side effects

As with any medication, Plan B (levonorgestrel) may cause side effects in some users. The most commonly reported adverse reactions associated with this morning after pill include nausea, which affects a significant proportion of women who take emergency contraception. Irregular or unexpected vaginal bleeding and spotting between periods are also frequently observed. Some women experience a delay in their next menstrual period by more than 7 days — if your period is delayed by more than one week, you should take a pregnancy test to rule out the possibility that the emergency birth control was unsuccessful. Other common side effects include dizziness, headache, and lower abdominal pain or cramping. Vomiting may occur, particularly within the first few hours after taking the tablet. Breast tenderness or a feeling of tension in the mammary glands is another frequently reported symptom. General fatigue and tiredness are also common in the days following use. Less common side effects may include diarrhea, changes in appetite, mood changes, and mild skin reactions. Most of these side effects are temporary and typically resolve within a few days. However, if you experience severe abdominal pain, heavy or prolonged bleeding, or signs of an allergic reaction such as difficulty breathing, swelling of the face or throat, or a severe rash, seek immediate medical attention. If side effects persist or worsen, contact your healthcare provider promptly.



Drug interaction

Several medications can interact with levonorgestrel and may significantly reduce the effectiveness of this emergency contraception. Drugs that induce liver enzymes accelerate the metabolism of levonorgestrel, potentially lowering its blood concentration below the level needed for effective pregnancy prevention. These include barbiturates (such as phenobarbital), primidone, phenytoin, and carbamazepine — all commonly used anticonvulsant medications. Herbal preparations containing St. John's wort (Hypericum perforatum) are also known to reduce the effectiveness of this morning after pill and should be avoided when using Plan B. The antibiotic rifampicin and the related drug rifabutin, used in the treatment of tuberculosis, are potent enzyme inducers that can substantially decrease levonorgestrel levels. The antiviral medication ritonavir, commonly used in HIV treatment, and the antifungal drug griseofulvin may similarly reduce the efficacy of this contraceptive pill. If you are taking any of these medications and need emergency birth control, consult your healthcare provider about potential dose adjustments or alternative emergency contraception methods. Conversely, products containing levonorgestrel may increase the blood levels and potential toxicity of cyclosporine, an immunosuppressant drug. Always inform your doctor or pharmacist about all medications, supplements, and herbal products you are currently taking before you buy Plan B online or use any levonorgestrel-based product.



Missed dose

The concept of a missed dose does not apply to Plan B in the traditional sense, as this emergency contraception is taken on an as-needed basis rather than on a regular schedule. However, timing is critical for maximum effectiveness. If you forget to take the second tablet within the recommended 12-hour window, take it as soon as you remember, provided no more than 16 hours have elapsed since the first dose. If more than 16 hours have passed, contact your healthcare provider for guidance. Remember that the effectiveness of this morning after pill decreases significantly with every hour of delay, so prompt administration is essential for optimal pregnancy prevention.



Overdose

In the event of a suspected overdose of levonorgestrel, symptoms may include severe nausea, vomiting, and vaginal bleeding or withdrawal bleeding. While a significant overdose of this emergency contraception is unlikely to be life-threatening, it may cause considerable discomfort and hormonal disruption. There is no specific antidote for levonorgestrel overdose. If you suspect that you or someone else has taken more than the recommended dose, contact your doctor, local poison control center, or emergency medical services immediately. Supportive care and symptom management are the standard treatment approaches. Do not attempt to self-treat an overdose situation.



Storage

Store Plan B (levonorgestrel) at controlled room temperature between 20-25°C (68-77°F). Brief excursions to temperatures between 15-30°C (59-86°F) are permitted but should be minimized. Keep the tablets in their original packaging until ready to use to protect them from environmental factors. Store away from excessive moisture, direct heat, and prolonged sunlight exposure, as these conditions may degrade the active ingredient and reduce effectiveness. Do not store this emergency contraception in a bathroom or other humid environment. Keep all medications, including this contraceptive pill, out of the reach and sight of children. Do not use Plan B after the expiration date printed on the packaging. If you buy Plan B online, ensure the product arrives in intact, sealed packaging and verify the expiration date before use. Dispose of expired or unused medication responsibly according to local guidelines — do not flush tablets or discard them in household waste unless specifically instructed to do so.



Disclaimer

This website provides only general informational content about medications, including Plan B (levonorgestrel) and other emergency contraception products. The information presented here does not cover every possible use, direction, precaution, drug interaction, or adverse effect. Nothing on this site should be interpreted as medical advice, and the content should not be used for self-diagnosis or self-treatment. When you buy levonorgestrel or any morning after pill, always consult with a qualified healthcare professional who can evaluate your individual medical history and circumstances. Any specific instructions regarding dosage, timing, or suitability for a particular patient must be discussed with and approved by your personal healthcare adviser or attending physician. We make every effort to ensure accuracy but disclaim responsibility for any errors or omissions this information may contain. We are not liable for any direct, indirect, incidental, special, or consequential damages resulting from the use of information on this site or from any decisions made based on this content, including consequences of self-treatment with any emergency birth control product.