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Mysimba FAQs

How does Mysimba work?

Mysimba is a prescription-only weight loss drug with two key ingredients, naltrexone and bupropion. Mysimba comes in tablet form with patients usually taking 1-2 a day, with a limit of 4 per day. The tablets work by reducing your appetite so that you are satisfied eating less, the active ingredients are also thought to curb cravings, reducing the desire to eat and making weight loss more achievable. Mysimba is used to treat those with an overweight BMI of 30 or more.

 

How effective is Mysimba?

For a medication to be licensed for sale, there is a thorough and rigorous amount of testing which must take place. Data published for the public by The European Medicines Agency explains that Mysimba was proven to be effective in reducing body weight in 4 main studies involving approximately 4500 obese or overweight patients. Patients in the studies were given the drug or a placebo in combination with a weight loss program involving counselling and advice on diet and exercise.

The European Medicines Agency goes on to explain:

"In three of the studies, the average weight loss in patients treated with Mysimba was around 3.7 to 5.7%, compared with 1.3 to 1.9% with placebo; the proportion of Mysimba-treated patients who achieved 5% weight loss ranged from 28 to 42% compared with 12 to 14% with placebo. About 13 to 22% of those taking Mysimba achieved at least a 10% reduction in weight, while 5 to 6% of placebo-treated patients did so.

In the other study, in which patient counselling was also more intensive, the overall weight loss was greater over the study period: 8.1% with Mysimba and 4.9% with placebo. Some 46% and 30% of patients given Mysimba achieved 5 and 10% weight reductions respectively, compared with 34% and 17% respectively with placebo.

The degree of improvement with Mysimba over placebo was similar using different methods of analysis, although the benefits were smallest with the most conservative methods that assumed patients who did not complete the study would not have seen any improvement. The treatment effect was more marked in patients who completed 56 weeks of treatment, or who had lost at least 5% of their original body weight by 4 months.

 

How do I take Mysimba?

Mediation should be taken as advised by us. When you take Mysimba you will gradually increase your dose over a four-week period until you reach what is called the maintenance dose. This is the dose at which you will continue to take Mysimba. You increase your dose as follows:

  • Week 1 - ONE tablet to be taken in the MORNING
  • Week 2 - ONE tablet to be taken in the MORNING & ONE tablet to be taken in the EVENING
  • Week 3 - TWO tablets to be taken in the MORNING & ONE to be taken in the EVENING
  • Week 4 - TWO tablets to be taken in the MORNING & TWO tablets to be taken in the EVENING
  • Maintenance Dose – Same as week 4

You should swallow your tablets whole with plenty of water, with or immediately after food. They are a prolonged-release formulation, so you must never crush, chew or cut the tablets as this will affect the rate at which the active ingredients are released into your body.

The maximum recommended dosage of Mysimba is two tablets twice a day. If you do not lose at least 5% of your body weight after 16 weeks of treatment, your doctor will evaluate if you should continue taking Mysimba.

Always take this medication exactly as your doctor tells you to. You can find full details in the patient information leaflet. Additional information and guidance on Mysimba can also be found at www.mysimba.co.uk.

Mysimba is a prolonged release tablet which is blue in colour. The tablets are round and have NB-890 embossed on one side.

 

What are the possible side effects of Mysimba?

As with all medication, Mysimba can be associated with unwanted side effects. Although generally mild some of these can be more severe which may result in the treatment being discontinued.

Very common side effects (may affect more than 1 in 10 people):

  • Insomnia
  • Anxiety & agitation
  • Headache
  • Feeling restless
  • Abdominal pain & constipation
  • Nausea & vomiting
  • Joint & muscular pain

Common side effects (may affect up to 1 in 10 people):

  • Hypersensitivity reactions (e.g. rash, itch)
  • Reduction in lymphocyte cells count
  • Depression, irritability & increased energy
  • Dizziness, vertigo & tinnitus
  • Tremor
  • Headache
  • Tiredness, difficulty concentrating & lack of energy
  • Watery eyes
  • Palpitations, hot flushes & excessive sweating
  • Chest pain
  • Decreased appetite, diarrhoea
  • Taste disturbances, dry mouth & toothache
  • Delayed ejaculation
  • Fever & chills
  • Hair loss

Uncommon side effects (may affect up to 1 in 100 people):

  • Cold sores
  • Athlete’s foot
  • Swollen glands in the neck, armpit or groin
  • Excessive loss of body water dehydration
  • Loss of appetite
  • Increased appetite & weight gain
  • Abnormal dreams, nightmares
  • Flushing
  • Feeling nervous, feeling spacey, tension, agitation, mood swings, hallucinations, confusion, severe suspiciousness (paranoia), disorientation
  • Loss of sexual desire
  • Tremor of the head or a limb which increases when trying to perform a particular function
  • Balance disorder
  • Loss of memory, mental impairment
  • Almost fainting
  • Motion sickness
  • Ear pain, ear discomfort
  • Visual disturbances, blurred vision, eye irritation, pain or swelling, increased sensitivity to light
  • Nasal discomfort, congestion, runny nose, sneezing, sinus disorder
  • Sore throat, increase in mucus that is coughed up, difficulty in breathing, disorder of the voice, cough, yawning
  • Fluctuating or increased blood pressure
  • Pain in the lower part of the abdomen
  • Burping
  • Swelling of the lips
  • Passage of fresh blood through the anus usually in or with stool
  • Hernia
  • Passing wind (flatulence), haemorrhoids, ulcer, cavities
  • Inflammation of the gallbladder
  • A problem with the spine where supporting disc between two bones (vertebra) bulges out
  • Jaw & groin pain
  • A disorder characterised by a sudden compelling urge to urinate, abnormally frequent urination, painful urination
  • Irregular menstrual cycle, vaginal bleeding, dryness of the female vulva & vagina
  • Difficulty in getting or keeping an erection
  • Feeling abnormal or weakness
  • Thirst, feeling hot
  • Coldness of extremities (hands, feet)
  • Increased creatinine levels in the blood (indicating loss of kidney function)
  • Increased liver enzymes and bilirubin levels, liver disorders, hepatitis
  • Decreased haematocrit (indicating loss of red blood cell volume)
  • Acne, oily skin

There are further rare and very rare side effects that occasionally people can experience when taking Mysimba, for complete details about all side effects always read the Patient Information Leaflet.

References
https://www.medicines.org.uk/emc/files/pil.2684.pdf 
https://www.medicines.org.uk/emc/files/pil.2684.pdf 
Side effect list compiled from data taken from www.medicines.org.uk – Please visit their website for a complete and comprehensive list. Medicines.org is a stand-alone entity and is in no way associated with this site.

 

Who cannot take Mysimba?

Mysimba cannot be used if:

  • you are pregnant, trying to become pregnant or are breastfeeding
  • you are under 18 or over 75 years old
  • you have any allergies to any of the ingredients in Mysimba or are taking any medicines that contain any of the active ingredients in Mysimba
  • you have severe liver disease, end-stage renal disease, uncontrolled hypertension, history of seizures or fits, CNS tumour, opioid dependence, acute alcohol, opioid or benzodiazepine withdrawal, history of bipolar disorder, bulimia or anorexia nervosa
  • you are taking monoamine oxidase inhibitors (MOI) – you must have at least a 14-day gap from stopping your MOI before starting Mysimba
  • you are taking any opiates or opiate-containing medicines (i.e. morphine, codeine, cough mixtures containing dextromethorphan, methadone) – you must have at least a 7-10-day gap before starting Mysimba

Mysimba should be used in caution if:

  • you are aged 65-75 years
  • you have liver or kidney problems
  • you have depression, suicidal thoughts or any other mental health condition
  • you have diabetes, high blood pressure or heart disease, have had a serious head injury, regularly drink alcohol or use sedatives, you have any drug addictions
  • you are taking any medicine that may increase the risk of fits or seizures

You must tell us about all the medications that you are taking including those that are prescribed, bought over the counter and also herbal remedies and supplements as they may interact with Mysimba and you will need to be monitored for side effects.