Side Effects of Xenical

There are risks and possible side effects of taking Xenical as with many other medications. However, Xenical has been made available to the public as a medication. This means that it has undergone trials to determine how effective it is at treating obesity, and to discover the possible side effects as well as how likely they are to occur. The results of these tests and trials have to show that the medication’s ability to treat obesity outweighs potential side effects in order for it to be made public. So it is worth considering while you are reading about the side effects of taking Xenical that many people feel that the resulting weight loss is worth these health complications.

How do I know if I will experience side effects while taking Xenical?

Different medications react differently with the human body. Some will produce side effects and others may not. In addition, some medications will cause quite different side effects to others. This makes it hard to be certain whether or not you will experience side effects and what those side effects will be.


It is therefore important that you are aware of possible side effects which you may experience while you are taking Xenical. If you do have any of these while you are having the medication then you can seek medical advice. This advice could be about whether to proceed with the medication, the possibility of changing the type of medication or to seek treatment for your side effects. If your side effects are especially severe, are reducing your ability to continue your usual routine or they are becoming harmful to your health then you may have to stop taking Xenical.

What are the side effects of Xenical?

The possible side effects from taking Xenical can be split into three categories. There are those side effects which are very common, those which are common (but less so than others) and side effects which we do not know how commonly they occur.

The very common side effects occur in one out of ten or more people (or 10% of people) who take Xenical and are as follows:

  • Flatulence.
  • Headaches.
  • Upper respiratory tract infection. This is an infection of one or all of these: throat, nose and sinuses. An example of a respiratory tract infection or RTI is the common cold.
  • Influenza.
  • Reduced blood sugar levels.
  • Oily rectal discharge.
  • Oily stools.
  • Stools which have a looser or liquid consistency.
  • Fatty stools.
  • Passing stools more frequently than is usual for you on an average day.
  • Stomach pain or discomfort in your stomach.

Unexpected urge to pass stools occurring more frequently than usual.

The common side effects occur in more than one in every one hundred people who are taking Xenical (or 1% of people), and are as follows:

  • Stomach distension (bloating or enlarging of the stomach).
  • Faecal incontinence, which is the inability to control the passing of stools.
  • Feelings of anxiety (being worried or nervous more often than normal or to a greater extent, possibly becoming agitated as a result).
  • Lower respiratory tract infection, which is an infection of your airways or lungs or both.
  • Irregular periods for women.
  • Pain in the area of your rectum along with rectal discomfort.
  • Softer stools or stools which are not fully formed.
  • Stomach swelling or bloating.
  • Tiredness and exhaustion.
  • Oral health complications such as tooth and gum problems, or pain in your teeth or mouth.
  • UTI, which may present symptoms of irregular discharge, needing the toilet with increased frequency and possibly pain originating from the urinary tract.

There are also some side effects where it is unknown how frequently they occur. These are listed below:

  • Laboratory tests may yield abnormal results.
  • Blood issuing from your rectum. If you experience bleeding from your rectum then you should contact the practitioner who prescribed you Xenical and seek medical attention.
  • Diarrhoea which can lead to dehydration. If you have diarrhoea you should try to stay hydrated as much as possible. Diarrhoea may also make oral contraceptives less effective, if you are using oral contraceptives and you have severe diarrhoea then it is highly advisable that you use another secondary form of contraceptive.
  • Diverticulitis, pancreatitis or other gastrointestinal problems.
  • Hypersensitivity reactions e.g. itchiness. Some can be fatal.
  • Taking Xenical may put you at an increased risk of attaining bone fractures due to an injury which would otherwise have a less severe effect.
  • Kidney, liver, skin or thyroid problems.

Side effects can also occur if you are using multiple medications at the same time, as they may interact with Xenical. It is possible that you will be instructed to take Xenical along with other medications because they will have an improved effect when used together. However, there may also be a higher risk of side effects or possibly different side effects which would not be caused by taking Xenical on its own. In such cases a decision will have to be made about whether the benefits of using multiple medications which interact with each other outweigh the potential risks of increased or different side effects.


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