How Effective Is Plan B?
When taken correctly, Plan B is up to 89% effective. Here’s what you need to know about when to take the pill and what makes it less effective.
levonorgestrel
Used for Emergency Contraceptive
Used for Emergency Contraceptive
Levonorgestrel (Plan B One-Step) works well to prevent pregnancy up to 72 hours after unprotected sex, but it won't stop a pregnancy that has already started and won't protect you from sexually transmitted infections (STIs).
What is Levonorgestrel (Plan B One-Step)?
What is Levonorgestrel (Plan B One-Step) used for?
- Emergency contraception
How Levonorgestrel (Plan B One-Step) works
Levonorgestrel (Plan B One-Step) is a progestin. It works to prevent pregnancy by temporarily stopping your ovaries from releasing an egg, by making it difficult for sperm to enter the uterus, and by preventing a fertilized egg from implanting in your uterus.
Drug facts
| Common Brands | Plan B One-Step, Take Action, My Choice, Next Choice, Aftera |
|---|---|
| Drug Class | Emergency contraceptive |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Over-the-counter |
Side effects of Levonorgestrel (Plan B One-Step)
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Next period is heavier than usual (31%)
- Nausea (14%)
- Lower stomach pain (13%)
- Tiredness (13%)
- Headache (10%)
Less Common Side Effects
- Dizziness
- Breast tenderness
- Next period is late by up to 7 days
Levonorgestrel (Plan B One-Step) serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Severe, unexplainable pelvic pain along with unusual vaginal bleeding (possible sign of an ectopic pregnancy)
The following Levonorgestrel (Plan B One-Step) side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
Get your GoodRx coupon
$50.20
GoodRx discount
$12.27
Pros and cons of Levonorgestrel (Plan B One-Step)
Pros
- Works with a single pill
- Anyone of any age can buy it
- Has mild and quick-passing side effects for most people
- Available over-the-counter with affordable generics available
Cons
- Can cause breakthrough bleeding or a late period
- Must be taken within 3 days of unprotected sex to work
- Won't stop an unwanted pregnancy that's already started
- Doesn't protect against HIV or other sexually transmitted infections (STIs)
Pharmacist tips for Levonorgestrel (Plan B One-Step)
- You can take levonorgestrel (Plan B One-Step) with or without food at any time. Nausea is a possible side effect, so if you tend to be sensitive to medications, taking this medication with food can help lessen the nausea.
- You must take levonorgestrel (Plan B One-Step) within 72 hours (3 days) from the time you have unprotected sex. The sooner you take it afterwards, the better it will work.
- If you vomit within 2 hours of taking levonorgestrel (Plan B One-Step), contact your healthcare provider. You might have to take another dose of this medication.
- You don't need a prescription to purchase levonorgestrel (Plan B One-Step), and there are no age restrictions to buy it. It should be located in the family planning section of the pharmacy or store you're buying it from.
- You can take levonorgestrel (Plan B One-Step) if you're breastfeeding. This medication is not known to be harmful to your baby, but some people do notice a temporary drop in milk supply after taking it.
- Levonorgestrel (Plan B One-Step) doesn't replace regular birth control. Birth control pills, patches, vaginal rings, the depo shot, IUDs, and the implant are all more effective than this medication. Consider other reliable options instead of using levonorgestrel (Plan B One-Step) as your only method of contraception.
- Levonorgestrel (Plan B One-Step) doesn't protect you from HIV or other sexually transmitted infections (STIs). Only abstinence and condoms can help prevent you from getting STIs. Talk to your provider right away if this is a concern for you.
Risks and warnings for Levonorgestrel (Plan B One-Step)
Levonorgestrel (Plan B One-Step) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Ectopic pregnancy
Ectopic pregnancies happen when a fertilized egg implants somewhere other than your uterus. They are very rare, but can be life-threatening and sometimes need to be treated with surgery. Progestin-only contraception, including levonorgestrel (Plan B One-Step), slightly raise your risk of ectopic pregnancies. Because levonorgestrel (Plan B One-Step) is only a single pill, your risk of this problem should stay low. If you experience unexplained or severe pelvic pain along with unusual vaginal bleeding between when you took this medication and your next period, let your provider know. If you do become pregnant after taking levonorgestrel (Plan B One-Step), make sure you tell your provider you took this medication so they can check to make sure it is not an ectopic pregnancy.
Don't take if already pregnant
- Risk factors: Pregnant
Levonorgestrel (Plan B One-Step) only helps prevent a pregnancy after unprotected sex. It doesn't stop a pregnancy that has already started. If you want to terminate a pregnancy, please speak with your provider. This is not a safe or good option for ending a pregnancy.
Sexually transmitted infections
Most birth control options, including emergency contraception like levonorgestrel (Plan B One-Step), don't protect against sexually transmitted infections (STIs), such as HIV. Condoms must be used to help protect you. Please tell your provider if you have had barrier-free sex and are worried about whether you might have gotten an STI.
Levonorgestrel (Plan B One-Step) dosage
The average cost for 1 tablet of 1.5mg of Levonorgestrel (Plan B One-Step) is $12.27 with a free GoodRx coupon. This is 51.08% off the average retail price of $25.08. 
Tablet
Tablet| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 1.5mg | 1 tablet | $12.27 | $12.27 |
Typical dosage for Levonorgestrel (Plan B One-Step)
A package of levonorgestrel (Plan B One-Step) contains a single tablet. Take the tablet within 72 hours of unprotected sex. The sooner after sex you take it, the more effective it will be.
How much does Levonorgestrel (Plan B One-Step) cost?
To access savings, use a GoodRx coupon and pay just a fraction of the retail price.
What are alternatives to Levonorgestrel (Plan B One-Step)?
There are a number of medications that your doctor can prescribe in place of Levonorgestrel (Plan B One-Step). Compare a few possible alternatives below.
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Levonorgestrel (Plan B One-Step) images
