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

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

Common Side Effects

• burping
• changed sense of taste
• constipation
• diarrhea
• dizziness or lightheadedness when rising from a lying or sitting position
• fatigue
• gas
• hair loss
• headache
• heartburn
• hemorrhoids
• injection site reactions (e.g., itching, redness, swelling, pain)
• nausea
• stomach ache and/or bloating
• vomiting
• weakness

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.

Serious Side Effects Requiring Prompt Medical Attention

• changes in mood
• delayed stomach emptying
• fast heartbeat
• feeling faint
• severe constipation (e.g., stomach ache, bloating, vomiting)
• signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of low blood glucose (e.g., anxiety, blurred vision, confusion, difficulty concentrating, difficulty speaking, dizziness, drowsiness, fast heartbeat, feeling jittery, headache, hunger, irritability, nausea, nervousness, numbness or tingling of the lips or tongue, sweating, tiredness, trembling, weakness)
• symptoms of a bowel obstruction (e.g., feeling of fullness or swelling in the belly, constipation, feeling gassy, unable to pass gas, severe belly pain, vomiting)
• symptoms of appendicitis (e.g., sudden pain in the middle or lower right abdomen, chills, fever, nausea, vomiting)
• symptoms of gallstones (e.g., intermittent, severe, dull pain in the upper right part of the abdomen, nausea, vomiting, intolerance of fatty or greasy foods)
• symptoms of kidney injury (e.g., swelling legs, ankles and feet, shortness of breath, confusion, fatigue, no urine production)
• vision changes caused by diabetic retinopathy (e.g., blurred or changing vision, floaters, changes in colour vision)

Immediate Medical Attention Required

• severe hypoglycemia (e.g., disorientation, loss of consciousness, seizures)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• symptoms of a serious allergic reaction (e.g., swelling of the face or throat, difficulty breathing, wheezing, or itchy skin rash)
• thoughts of suicide or self-harm

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 this medication.

Solution for Injection Multi-Use Pen

0.25 mg

Each prefilled pen contains 1 mg of Wegovy (Semaglutide) in 1.5 mL, delivering 4 doses of 0.25 mg. Nonmedicinal ingredients: disodium phosphate dihydrate, propylene glycol, phenol, hydrochloric acid, sodium hydroxide, and water for injection.

0.5 mg

Each prefilled pen contains 2 mg of Wegovy (Semaglutide) in 1.5 mL, delivering 4 doses of 0.5 mg. Nonmedicinal ingredients: disodium phosphate dihydrate, propylene glycol, phenol, hydrochloric acid, sodium hydroxide, and water for injection.

1 mg

Each prefilled pen contains 4 mg of Wegovy (Semaglutide) in 3 mL, delivering 4 doses of 1 mg. Nonmedicinal ingredients: disodium phosphate dihydrate, propylene glycol, phenol, hydrochloric acid, sodium hydroxide, and water for injection.

1.7 mg

Each prefilled pen contains 6.8 mg of Wegovy (Semaglutide) in 3 mL, delivering 4 doses of 1.7 mg. Nonmedicinal ingredients: disodium phosphate dihydrate, propylene glycol, phenol, hydrochloric acid, sodium hydroxide, and water for injection.

2.4 mg

Each prefilled pen contains 9.6 mg of Wegovy (Semaglutide) in 3 mL, delivering 4 doses of 2.4 mg. Nonmedicinal ingredients: disodium phosphate dihydrate, propylene glycol, phenol, hydrochloric acid, sodium hydroxide, and water for injection.

Do not take this medication if you:

• are allergic to Wegovy (Semaglutide) or any ingredients of the medication
• are pregnant
• are breast-feeding
• have a personal or family history of thyroid cancer
• have multiple endocrine neoplasia syndrome type 2 (a disease where people have tumours in more than one gland in their body)

There may be an interaction between Wegovy (Semaglutide) and any of the following:

• acetylsalicylic acid (ASA)
• antipsychotics (e.g., aripiprazole, cariprazine, clozapine, olanzapine, quetiapine, risperidone)
• basiliximab
• beta adrenergic blockers (e.g., acebutolol, atenolol, carvedilol, labetalol, propranolol, sotalol)
• bismuth subsalicylate
• buserelin
• corticosteroids (e.g., beclomethasone, cortisone, dexamethasone, hydrocortisone, prednisone)
• danazol
• decongestants (e.g., phenylephrine, pseudoephedrine)
• diazoxide
• disopyramide
• diuretics (e.g., furosemide, hydrochlorothiazide, indapamide)
• elagolix
• epinephrine
• estrogens (e.g., estradiol, ethinyl estradiol, conjugated estrogen)
• everolimus
• GLP-1 agonists (e.g., dulaglutide, liraglutide)
• glucagon
• goserelin
• Hepatitis C antivirals (e.g., elbasvir and grazoprevir, glecaprevir and pibrentasvir, ledipasvir, velpatasvir, voxilaprevir)
• HIV protease inhibitors (e.g., atazanavir, lopinavir, ritonavir, tipranavir)
• hydroxychloroquine
• insulin and insulin secretagogues (e.g., gliclazide, glimepiride, glyburide)
• leuprolide
• levothyroxine
• linezolid
• mifepristone
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
• niacin
• pegvisomant
• progestins (e.g., cyproterone, levonorgestrel, medroxyprogesterone, norethindrone, progesterone)
• protein kinase inhibitors (e.g., bortezomib, ceritinib, dabrafenib, nilotinib, sunitinib)
• quinolone antibiotics (e.g., ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• sirolimus
• somatostatin analogues (e.g., lanreotide, octreotide, pasireotide)
• somatrogon
• somatropin
• sulfamethoxazole
• tacrolimus
• temsirolimus
• terbutaline
• testosterone
• tramadol
• venetoclax
• vilazodone
• vorinostat

If you are taking other 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.

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 this medication.

Dehydration: Symptoms of nausea, vomiting, and diarrhea may be more common at the start of treatment and can result in loss of fluid from the body. If you experience symptoms of dehydration, such as thirst, decreased urine or tear production, dizziness or headaches, contact your doctor.

Gallstones: Wegovy (Semaglutide) has been associated with an increase in gallstone formation. Gallstones often form when there is significant or fast weight loss. If you experience symptoms of gallstones, such as nausea and vomiting, pain under the right shoulder or between the shoulder blades or severe abdominal pain, contact your doctor as soon as possible.

Heart problems: This medication may increase heart rate and may affect how electrical impulses travel through the heart muscle. If you have heart disease (e.g., recent heart attack, angina, heart failure) or an abnormal heart rhythm (e.g., heart block or fast heart rate), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Intestinal problems: Wegovy (Semaglutide) may slow down the speed that material passes through the digestive system. If you have digestive system problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney function: Decreased kidney function has been reported with the use of Wegovy (Semaglutide). This may be more likely to occur if you have reduced kidney function when you start using this medication. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: The safety and effectiveness of using this medication for people with reduced liver function have not been studied. If you have reduced liver function or liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Low blood glucose (hypoglycemia): People who use Wegovy (Semaglutide) may experience low blood sugar. This may be more likely if you are also taking a sulfonylurea (e.g., glyburide, gliclazide) to control high blood sugar. If you experience symptoms of hypoglycemia such as a cold sweat, nervousness or shakiness, fast heartbeat, headache, hunger, confusion, lightheadedness, weakness, and numbness or tingling of the tongue or lips, contact your doctor.

Pancreatitis (inflammation of the pancreas): Wegovy (Semaglutide) can cause pancreatitis. If you experience symptoms of pancreatitis such as severe and persistent abdominal pain that may move to the back with or without vomiting, contact your doctor immediately. If you have previously had pancreatitis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Thyroid cancer: In rare cases, people have developed thyroid cancer while using Wegovy (Semaglutide). People with a personal or family history of thyroid cancer or people who have multiple endocrine neoplasia syndrome type 2 (a disease where people have tumours in more than one gland in their body) should not use this medication.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Use effective birth control while you are using this medication and for at least 2 months after your last dose of Wegovy (Semaglutide).

Breast-feeding: It is not known if Wegovy (Semaglutide) passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 12 years of age. Adolescents must weigh at least 60 kg or have a BMI of at least 30 kg/m2.

Seniors: Seniors may be at an increased risk of experiencing side effects of Wegovy (Semaglutide).