Plan B is a preparation applied for an emergency contraception. The main component – levonorgestrel
Indications for use
Mechanism of action
When administered orally in the recommended dosage, Plan B suppresses ovulation and fertilization if sexual intercourse takes place in the preovulatory period, when the level of fertilization is greatest. It can also cause changes in the endometrium, which prevent a fertilized egg’s implantation. It magnifies the viscosity of the cervical secretion, which prevents the spermatozoa attachment. Plan B is ineffective if an attachment has already occurred.
Mode of application and dosage
Plan B should be applied within 24 – 48 hours after sexual intercourse. It is 95% effective if it is taken within 24 hours after unprotected sexual intercourse. Effectiveness drops to 89% if taken for 3 days.
Hypersensitivity to Plan B pill is a contraindication to its application.
In addition, Plan B is forbidden to be taken if you have the following conditions:
- liver disease;
- anamnesis of breast cancer;
- undiagnosed vaginal bleeding;
- liver failure;
- severe arterial disease;
- Mammary glands tenderness;
- Irregular and spotting bleeding;
- Lower abdomen pain;
- Temporary disruption of the normal menstrual cycle;
- Unexpected hemorrhages;
These side effects were fixed earlier, but not on a constant basis. Some of these side effects can occur extremely rarely but have incredibly serious consequences. If any side effects are found, contact your doctor immediately especially in case of observing side effects for a long time.
With the simultaneous use of drugs – inducers of liver microsomal enzymes, there is an acceleration of the levonorgestrel metabolism.
The following drugs may decrease the effectiveness of Plan B: amprenavir, lansoprazole, nevirapine, oxcarbazepine, tacrolimus, topiramate, tretinoin, barbiturates (including primidone), phenobarbital, phenytoin and carbamazepine, drugs containing St. John’s wort (Hypericum perforatum), rifampicin, ritonavir, ampicillin, tetracycline, rifabutin, griseofulvin, efavirenz. Levonorgestrel reduces the effectiveness of hypoglycemic and anticoagulant (coumarin derivatives) drugs.
Plan B can reduce the effectiveness of vaginal injury by competing with the progesterone receptor. Therefore, a simultaneous use of drugs containing levonorgestrel, ulipristal acetate is not recommended.
Levonorgestrel and pregnancy
Plan B should not be taken during pregnancy. If the pregnancy has developed on the background of its reception, then, based on the available data, the side effect of this preparation on the fetus is not expected.
This birth control drug penetrates into the breast milk. After taking it, breastfeeding should be arrested within 24 hours.