Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Norlevo (Levonorgestrel). If you are concerned about side effects, discuss the risks and benefits of Norlevo (Levonorgestrel) with your doctor.

The following side effects have been reported by at least 1% of people taking Norlevo (Levonorgestrel). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• breast tenderness
• Diarrhea
• dizziness
• fatigue
• headache
• irregular, altered, or heavier menstrual bleeding
• migraine
• nausea
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• cramping or severe abdominal pain before your next normal period
• itching
• painful menstruation
• skin rash
• vaginal discharge
• very heavy vaginal bleeding

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Norlevo (Levonorgestrel).

Do not take Norlevo (Levonorgestrel) if you:

• are allergic to Norlevo (Levonorgestrel) or any ingredients of Norlevo (Levonorgestrel)
• are or may be pregnant
• have undiagnosed abnormal vaginal bleeding

There may be an interaction between Norlevo (Levonorgestrel) and any of the following:

• acitretin
• antibiotics (ampicillin, cotrimoxazole, Tetracycline, clarithromycin)
• Apixaban
• Aprepitant
• barbiturates (e.g., pentobarbital, Phenobarbital)
• Bosentan
• cannabis
• Carbamazepine
• Cholestyramine
• Colestipol
• Clobazam
• Cobicistat
• Cyclosporine
• dabigatran
• Dabrafenib
• darunavir
• Deferasirox
• diabetes medications (e.g., Canagliflozin, Glyburide, insulin, Metformin, Rosiglitazone)
• Edoxaban
• efavirenz
• Eslicarbazepine
• Exenatide
• fosaprepitant
• fosphenytoin
• Heparin
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• Isotretinoin
• Lamotrigine
• low-molecular-weight heparins (e.g., Dalteparin, Enoxaparin, Tinzaparin)
• lumacaftor and Ivacaftor
• mifepristone
• Modafinil
• mycophenolate
• nevirapine
• Octreotide
• Oxcarbazepine
• Perampanel
• Phenytoin
• primidone
• rifampin
• rifabutin
• Rivaroxaban
• St. John's wort
• Sarilumab
• Selegiline
• siltuximab
• thalidomide
• Tocilizumab
• Topiramate
• Tranexamic acid
• Triazolam
• tretinoin
• Ulipristal
• Voriconazole
• Warfarin

Because only one tablet of Norlevo (Levonorgestrel) is taken, the effects of these medications on how the  Norlevo (Levonorgestrel) works is likely to be minimal. If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Norlevo (Levonorgestrel). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, decongestants, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Norlevo (Levonorgestrel).

Decreased effectiveness: This medication may be less  effective for women who weigh more than 165 pounds (75 kg) . Regardless of body weight, Norlevo (Levonorgestrel) should be taken as soon after unprotected intercourse as possible to ensure the most reliable outcome. If you weigh more than 165 pounds, you may wish to contact your doctor or pharmacist for advice about emergency contraception.

Diabetes: Although few women have experienced loss of blood glucose control when taking progestin-only pills, women with diabetes should monitor their blood glucose carefully after taking Norlevo (Levonorgestrel).

Liver problems: The safety of using Norlevo (Levonorgestrel) has not been established for people with liver disease. If you have liver disease, discuss with your doctor whether any special monitoring is needed.

Migraine: After taking a dose of Norlevo (Levonorgestrel), you may experience a severe headache or a migraine.

Sexually transmitted infections: This medication does not protect against sexually transmitted infections, including HIV or AIDS. For protection against these infections, latex condoms should be used.

Pregnancy: Norlevo (Levonorgestrel) should not be used during pregnancy. It will not terminate a pregnancy that has already been established.

Breast-feeding: Small amounts of progestin pass into the breast milk of women taking progestin-only pills. No adverse effects have been found with taking Norlevo (Levonorgestrel) while breast-feeding, either in the quality and quantity of milk or in the growth and development of the infant.