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 Seasonale. If you are concerned about side effects, discuss the risks and benefits of Seasonale with your doctor.

The following side effects have been reported by at least 1% of people taking Seasonale. 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.

• back pain
• bleeding or spotting between menstrual periods
• breast tenderness
• contact lens discomfort
• diarrhea
• gas
• nausea
• vomiting
• weight gain

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

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

• amenorrhea (lack of a period)
• breast lumps
• darkening of the skin (particularly on the face)
• dizziness
• flu-like symptoms
• fluid retention (unusual swelling of extremities)
• headache (severe)
• loss of scalp hair
• nervousness
• pain or tenderness in the abdomen (stomach area)
• trouble sleeping
• upper respiratory tract infections (e.g., colds, Bronchitis, runny or stuffy nose, sore throat)
• vaginal infections

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a blood clot in blood vessels (e.g., sudden loss of vision or change in vision, pain in the chest, groin, or leg [especially with swelling in the calf of the leg], sudden or unexplained shortness of breath)
• signs of Depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
• significant increases in blood pressure
• signs of an allergic reaction (e.g., shortness of breath or difficulty breathing; Hives; swelling of the eyes, mouth, lips, or throat)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• signs of a stroke (e.g., headache, loss of coordination, slurred speech, weakness, numbness, or unexplained pain in the arm or leg)
• sudden partial or complete loss of vision

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 Seasonale.

Active tablets
Each pink, round, film-coated, biconvex, unscored tablet, debossed with "S" on one side and "62" on the other side, contains 0.15 mg of levonorgestrel and 0.03 mg of ethinyl estradiol. Nonmedicinal ingredients: anhydrous lactose, FD&C Blue No. 1, FD&C Red No. 40, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, and titanium dioxide.

Inactive tablets
Each white, round, biconvex, unscored tablet, debossed with "S" on one side and "197" on the other side, contains no active ingredients. Nonmedicinal ingredients: anhydrous lactose, hydroxypropyl methylcellulose, magnesium stearate, and microcrystalline cellulose.

Levonorgestrel - ethinyl estradiol (extended cycle) should not be taken by anyone who:

• is allergic to levonorgestrel, ethinyl estradiol, or to any of the ingredients of the medication
• is or may be pregnant
• has active liver disease
• has any eye lesion resulting from blood vessel disease of the eye, such as partial or complete loss of vision or defects in visual fields
• has, has had, or may have Breast Cancer
• has heart valve disease with complications
• has or has had a Heart Attack or heart disease (e.g., Angina pectoris)
• has or has had benign or malignant liver tumours
• has or has had cerebrovascular disorders (e.g., Stroke or "mini-stroke" [transient ischemic attacks, or TIAs])
• has or has had jaundice (yellowing of skin or whites of the eyes) during pregnancy or while on hormonal medications (e.g., birth control pills)
• has or has had migraine Headaches
• has or has had Thrombophlebitis or thromboembolic (blood clotting) disorders
• has or may have an endometrium (lining of the uterus) tumour, or other suspected or diagnosed estrogen-dependent tumours
• has risk factors for developing Blood Clots, including:
• Diabetes with complications
• heavy smoking (more than 15 cigarettes per day) and over the age of 35
• high blood cholesterol or triglyceride levels
• known abnormalities of the blood clotting system that increases the risk for developing blood clots
• prolonged bed rest
• recent or scheduled major surgery
• severe high blood pressure
• has undiagnosed abnormal vaginal bleeding
• have or have had pancreatitis with high triglycerides

There may be an interaction between levonorgestrel - ethinyl estradiol (extended cycle) and any of the following:

• Acetaminophen
• acetylsalicylic acid (Asa)
• acitretin
• Adapalene
• alcohol
• Amiodarone
• Anastrozole
• antacids
• antibiotics (e.g., ampicillin, chloramphenicol, cotrimoxazole, Metronidazole, neomycin, Nitrofurantoin, penicillin, rifampin, sulfonamides, tetracyclines)
• Apixaban
• Aprepitant
• Aripiprazole
• Atorvastatin
• "azole" antifungals (e.g., itraconazole, ketoconazole, Voriconazole)
• barbiturates (e.g., butalbital, pentobarbital, Phenobarbital)
• benzodiazepines (e.g., Diazepam, Lorazepam, Oxazepam)
• boceprevir
• Bosentan
• caffeine
• Celecoxib
• chloral hydrate
• cholesterol-lowering medications (e.g., Cholestyramine, Colestipol, clofibrate)
• Clomipramine
• Clonidine
• Clozapine
• conivaptan
• corticosteroids (e.g., Dexamethasone, Prednisone, Hydrocortisone)
• Cyclosporine
• Cyclobenzaprine
• dabigatran
• Dabrafenib
• Dacarbazine
• Deferasirox
• dofetilide
• dehydroepiandrosterone
• other estrogens (estradiol, conjugated/equine, esterified, Estropipate
• Exenatide
• Flunarizine
• Flutamide
• Heparin
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delavirdine, efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• hyaluronidase 
• Hydrocodone
• Isotretinoin
• lidocaine
• Lomitapide
• low molecular weight heparins (e.g., Dalteparin, Enoxaparin, Tinzaparin)
• medications for diabetes
• medications that are used to treat high blood pressure
• Mexiletine
• mifepristone
• Mirtazapine
• Mitotane
• Modafinil
• mycophenolate
• nefazodone
• Olanzapine
• penicillin
• Perampanel
• Pimozide
• phenothiazines (e.g., Chlorpromazine)
• Prucalopride
• Rasagiline
• rifabutin
• rifampin
• Rivaroxaban
• Rufinamide
• Ropinirole
• St. John's wort
• seizure medications (e.g., Clobazam, Ethosuximide, felbamate, Levetiracetam, phenobarbital, Phenytoin, primidone, Topiramate, Valproic acid, zonisamide)
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Duloxetine, Fluoxetine, Paroxetine, Sertraline)
• Selegiline
• siltuximab
• sulfonamides (e.g., co-trimoxazole, sulfisoxazole, sulfamethoxazole)
• tetracyclines
• thalidomide
• theophyllines (e.g., Aminophylline, Oxtriphylline, Theophylline)
• Thyroid replacements (e.g., dessicated thyroid, Levothyroxine)
• Tizanidine
• Tocilizumab
• Tranexamic acid
• tretinoin
• Ulipristal
• vitamin C
• Venlafaxine
• Warfarin
• Zopiclone

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 Seasonale. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, 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 Seasonale.

Blood clots: Blood clots are the most common serious side effects of birth control pills. Developing blood clots is especially high during the first year a woman ever uses a hormonal contraceptive. Clots can occur in many parts of the body (brain, eyes, heart, legs, or lungs). If you notice any of the following signs or symptoms that may suggest a potential clot, notify your doctor immediately.

• crushing chest pain or heaviness may indicate a possible heart attack
• pain or swelling in the calf may suggest a possible blood clot in the leg
• sharp pain in the chest, coughing blood, or sudden shortness of breath may indicate a possible blood clot in the lung
• sudden partial or complete loss of vision may indicate a blood clot in the eye
• sudden severe or worsening headache, vomiting, dizziness or fainting, disturbances of vision or speech, or weakness or numbness in an arm or leg may suggest a stroke

People with a blood clot or history of blood clot should not use Seasonale (See "Who should NOT take Seasonale?").

Blood pressure: People with high blood pressure should discuss with their doctor how Seasonale may affect their medical condition, and whether any special monitoring is needed. The use of Seasonale is not recommended in people with severe or uncontrolled high blood pressure.

Breast cancer: The chance of having breast cancer diagnosed may be slightly higher in women who use birth control pills, especially if you started using them at a younger age. You should have regular breast examinations by your doctor and examine your own breasts regularly. Women who currently have or have had breast cancer should not use birth control pills because the hormones in the pills may stimulate the cancer to grow. People who have or have had breast cancer should not use Seasonale (See "Who should NOT take Seasonale?").

Cervical cancer: Some studies have found an increase of cancer of the cervix in women who use birth control pills. This finding may be related to other factors other than the use of birth control pills. However, there is insufficient evidence to rule out the possibility that birth control pills may cause such cancers.

Cholesterol: Blood cholesterol or triglyceride levels may increase while taking Seasonale. People with cholesterol problems should discuss with their doctor how Seasonale may affect their medical condition, and whether any special monitoring is needed.

Cigarette smoking: Cigarette smoking increases the risk of serious heart disease and death. Birth control pills increase this risk, especially with increasing age (over 35 years of age). All women are urged not to smoke while taking Seasonale.

Diabetes: Birth control pills can affect blood sugar. People with diabetes or those with a family history of diabetes should discuss with their doctor how Seasonale may affect their medical condition, and whether any special monitoring is needed.

Emotional problems: Women with a history of emotional problems, especially depression, may be more likely to have a recurrence of their condition while taking birth control pills. If you notice your condition worsen while on Seasonale, consult your doctor.

Eye problems: Women who are taking birth control pills may experience fluid buildup in the cornea of the eye, which can lead to visual disturbances and changes in tolerance to contact lenses, especially the rigid type. Disturbances usually do not occur with soft contact lenses. If you experience visual changes or difficulty wearing your contact lenses, consult your doctor.

Fibroids: Seasonale may worsen fibroids, causing sudden enlargement, pain, or tenderness. If you notice these effects, contact your doctor.

Gallbladder disease: Women who use birth control pills have a greater risk of developing gallbladder disease. If you notice severe pain in the abdomen (stomach area), Fever, or yellowing of skin or eyes (jaundice), contact your doctor immediately.

Heart diseases: Women at high risk for heart disease such as those with diabetes, high blood pressure, abnormal cholesterol levels, or a family history of these conditions should discuss with their doctor how Seasonale may affect their medical condition, and whether any special monitoring is needed.

Liver disease: Though rare, birth control pills can cause liver problems. If you develop yellowing of the eyes or skin, fever, fatigue, loss of appetite, dark urine, or light-coloured stools, stop taking the medication and contact your doctor.

Liver tumours: The short- and long-term use of birth control pills has been linked to the growth of liver tumours. Contact your doctor immediately if you notice yellowing of your skin or whites of your eyes, fever, fatigue, loss of appetite, dark urine, or pale stools. Stop taking the medication and talk to your doctor. People who have or have had liver tumours should not use birth control pills (See "Who should NOT take Seasonale?").

Migraine and headaches: The onset or worsening of a migraine or the development of new types of recurrent, persistent, or severe headaches should be reported to your doctor.

Regular checkups: Physical examinations and follow-up visits with your doctor should be done 3 months after starting Seasonale and then yearly thereafter.

Return to fertility: After stopping birth control therapy, you should delay getting pregnant until at least one normal spontaneous menstrual cycle has occurred in order to date the pregnancy. An alternative birth control method should be used during this time. If you do not menstruate for 6 months or more after stopping birth control pills, notify your doctor.

Sexually transmitted infections (STIs): Birth control pills do not protect against STIs, including HIV/AIDS. For protection against these diseases, use latex condoms in combination with birth control pills.

Pregnancy: Do not take birth control pills if you are pregnant. If you become pregnant while taking birth control pills, contact your doctor immediately.

Breast-feeding: The hormonal components of Seasonale passes into breast milk and may reduce the quantity and quality of breast milk. The use of Seasonale is not recommended for breast-feeding women.

Children and adolescents: The safety and effectiveness of using Seasonale have not been established for children and adolescents under 18 years of age. The use of Seasonale is not recommended before menarche (first menstrual period).

Seniors: The use of birth control pills is not recommended for postmenopausal women.