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The Side Effects of Mysimba

If you're taking Mysimba you should know potential side effects & what to do if you experience them. We look at the most common side effects.

If you’re considering asking your doctor or prescriber about Mysimba, you may have already started wondering what treatment could be like.

Some of the most common questions our healthcare team hear from patients considering Mysimba are about the potential side effects.

That’s why we’re here to let you know what the most common side effects of this weight loss treatment are and what you should be looking out for if it’s prescribed to you.

Let’s start by looking at the symptoms patients are most likely to experience.

What are the most common side effects of Mysimba?

There are four potential side effects of Mysimba that are more common than any others on the list, believed to affect more than 1 in 10 people during treatment.

These side effects are feeling sick (nausea), being sick (vomiting), constipation, and headaches.

As you may have noticed, three of the four of these are digestive problems, so you may want to prepare for an unhappy tummy before you take Mysimba for the first time.

Some bland foods that won’t make you feel worse if you do feel sick and plenty of fibre rich foods to help you through any constipation should do the trick, but you can also ask your prescriber to see if they have other advice too.

The next tier of common side effects is a bit broader, with these symptoms believed to affect up to 1 in 10 people who take Mysimba.

The list includes:

  • Anxiety
  • Feeling dizzy or like you’re “spinning” (vertigo)
  • Feeling shaky
  • Difficulty sleeping (insomnia)
  • Changes to the taste of food, dry mouth
  • Difficulty concentrating
  • Feeling tired and sleepy, drowsy or lacking energy
  • Ringing in your ears
  • A fast or irregular heartbeat (palpitations)
  • Hot flushes
  • An increase in your blood pressure
  • Pain in your abdomen or upper abdomen
  • Excessive sweating
  • A rash, itching
  • Hair loss
  • Feeling irritable
  • Feeling jittery

Of course, you can’t prepare for every one of these extensively, but as long as you’re aware of them you’re already ahead of the game.

Are there any serious side effects I should look out for?


Yes, there are serious side effects that you should look out for when you’re taking Mysimba, as they would need immediate medical attention if you experience them.

The first to look out for is a change in your mood, specifically feelings of depression or suicidal thoughts.

As Mysimba is known to work by affecting your brain, any changes to your mental health should be noted after you start treatment.

If you find yourself experiencing distressing thoughts, contact a medical professional or an appropriate crisis helpline right away, they will be able to help.

The next serious side effects we would like to address are physical, rather than mental.

The first of these is a fit or a seizure.

You may not remember having a fit after you have one, so make sure you have someone around who could help you get medical help if you needed it.


The other severe side effects to look out for are symptoms of the following conditions:

  • Erythema multiforme and Stevens-Johnson Syndrome
  • Rhabdomyolysis
  • Lupus skin rash or a worsening of lupus symptoms
  • Serotonin syndrome

How often patients can experience symptoms of these serious conditions is currently unknown, as professionals have not been able to make a thorough assessment using the data they have at the moment

The best thing you can do is make sure you’re familiar with these conditions and their side effects, so you’ll know when to get medical help.

You will be able to find some information in the patient information leaflet included with Mysimba tablets if you have a prescription.

What should I do if I experience side effects?


What you should do if you experience any side effects while taking Mysimba will depend on the severity of your symptoms.

If your symptoms aren’t particularly bad and aren’t associated with severe side effects, you should speak to your doctor or local pharmacist as soon as you can.

You may also consider calling 111 if you’re struggling to go to a local healthcare team or need to speak with someone outside of regular working hours for healthcare workers.

If your symptoms are severe or are associated with the serious side effects we mentioned earlier, you should contact 999 or go to your local A&E for emergency medical assistance.

Remember that it’s always wise to seek medical help when you need it — it’s better to be safe than sorry!

How do I manage unwanted symptoms caused by Mysimba?


If your side effects aren’t severe, your healthcare team may advise you to stick it out for a little while to give your body a chance to get used to the treatment.

Over time, your symptoms should settle down a bit, so you may be advised to manage them at home until that happens.

If you’re one of our patients and you’re experiencing side effects at any stage of your treatment, you should get in touch with us right away.

Your treatment plan doesn’t just cover the cost of your consultation and any weight loss prescriptions, but it can also include complimentary prescriptions to help you manage your symptoms.

For example, our prescribers may recommend some pain relief to help you manage headaches or a laxative if you’re experiencing constipation.

Our team are always here to help, so don’t be afraid to call!

Remember though, if your symptoms are severe, you should always seek emergency medical assistance from local services like A&E.

Why do you need to increase your dosage of Mysimba slowly?


When you start taking Mysimba, you’ll be given the lowest possible dose and given a dosage schedule that will slowly bring you to the highest possible dose.

This is designed to help reduce the potential side effects of this medication, giving your body time to adjust to treatment along the way.

If you are still experiencing side effects, your prescriber may slow down your dosage schedule a little to help you adjust or may end your treatment altogether.

There’s nothing wrong with this, the system is here to help you find the right treatment for you and get you the weight loss results you need.

Now we’ve learned a lot more about the potential side effects of Mysimba and what you can do to help yourself through those first stages of treatment.

Remember, if you experience any side effects or are worried in any way you should contact a medical professional for help — it’s what they’re there for!

Want to learn more about weight management treatments? Here are some of our other most popular articles, go ahead, give them a read!

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Laura Henderson

Laura Henderson

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