In rare instances, serious side effects may occur while taking weight management injections such as Mounjaro® or Wegovy®.
Knowing what symptoms to look out for means you can act quickly if something isn't right.
If you feel very unwell or believe you are experiencing a serious side effect, stop treatment and seek medical attention. Make sure the healthcare professionals treating you are aware that you are taking Mounjaro® or Wegovy®.
Acute pancreatitis
Acute pancreatitis is inflammation of the pancreas.
Symptoms can include severe, persistent stomach pain that may spread to your back and may occur with nausea or vomiting.
If you experience symptoms that could indicate pancreatitis, contact NHS 111 or attend A&E for urgent assessment.
Hypoglycaemia (low blood sugar)
Low blood sugar can occur, particularly if you have diabetes and are taking certain diabetes medicines alongside your weight management treatment.
Symptoms can include:
- Shaking
- Sweating
- Weakness
- Dizziness
- Hunger
- Confusion
- A fast heartbeat
If you experience symptoms of low blood sugar, follow the hypoglycaemia advice provided by your healthcare professional and take a source of fast-acting sugar if you are able to do so.
If symptoms do not improve, contact NHS 111.
If you become severely confused, very drowsy, collapse or lose consciousness, call 999 immediately.
Serious allergic reaction
Signs of a serious allergic reaction can include:
- Swelling of your face, lips, tongue or throat
- Difficulty breathing or wheezing
- A severe or widespread rash
- Clammy skin
- Feeling faint or collapsing
- Loss of consciousness
Call 999 immediately if you experience signs of a serious allergic reaction.
Kidney problems and dehydration
Vomiting and diarrhoea can cause significant dehydration, which can affect how well your kidneys work.
Warning signs can include:
- Passing much less urine than usual
- Dark urine
- Swelling in your legs or ankles
- Feeling significantly dehydrated or unwell
If you develop these symptoms, particularly after persistent vomiting or diarrhoea, contact NHS 111 or seek same-day medical advice.
Severe stomach problems
Seek urgent medical advice if you experience:
- Severe or persistent abdominal pain
- Significant abdominal bloating or swelling
- Persistent vomiting
- Severe constipation accompanied by abdominal pain, bloating or vomiting
Contact NHS 111 or attend A&E, depending on the severity of your symptoms.
Changes to your vision
Seek urgent medical attention if you experience a sudden or significant change to your eyesight.
Symptoms can include blurred vision, shapes floating in your vision or sudden loss of vision.
Very rarely, semaglutide (Wegovy®) has been linked to an eye condition called non-arteritic anterior ischaemic optic neuropathy (NAION), which can cause sudden, painless loss or worsening of vision, usually in one eye.
If you experience a sudden change or loss of vision while taking Wegovy®, stop taking Wegovy® and seek urgent assessment at an eye casualty department or A&E. If you are unsure where to attend, contact NHS 111 for advice.
Gallbladder problems
Mounjaro® and Wegovy® can be associated with gallbladder problems, including gallstones.
Symptoms can include sudden or severe pain in the upper right side or centre of your abdomen, which may spread towards your back or right shoulder.
If the pain is severe or accompanied by fever or yellowing of your skin or eyes, contact NHS 111 or seek urgent in-person medical attention.
Please let us know
If you experience any of the serious side effects above, please also contact Simple Online Pharmacy as soon as possible once you have received the appropriate medical attention.
Our Clinical Team can review what has happened and advise you on the appropriate next steps with your treatment.