What are the main side effects of Carbimazole?

Carbimazole is a type of drug used in treatment of hyperthyroidism. Another drug that is used for the same treatment is propylthiouracil. It works by reducing the production of the thyroid hormone and to bring back the thyroid hormone to its normal level range.

Overproduction of thyroid hormone can leads to hyperthyroidism and later thyrotoxicosis which can causes symptoms such as:

  • Palpitations
  • Tremors
  • Sweating
  • Diarrhea
  • Sleep disturbances
  • Swelling in the middle of the neck (goiter)
  • Anxiety, nervousness and irritability
  • Unexplained weight loss despite having regular meal pattern
  • Menstrual disturbances in women

Once an individual with the symptoms mentioned above sees a doctor and the diagnosis of hyperthyroidism has been made, treatment can be commenced immediately and medical treatment with medication is one of them. Medical treatment includes the use of antithyroid drugs such as carbimazole and propylthiouracil and the prescription is depending on the patient’s condition and the resource available.

Carbimazole is the most widely prescribed antithyroid medication and it is taken orally. Just like any other medications, carbimazole has its own side effects, such as:

  • Gastrointestinal disturbances (diarrhea, constipation, nausea, vomiting); this is the most common side effects of carbimazole and it usually resolve by itself or by staying hydrated
  • Headache
  • Alteration in taste
  • Joint pain; taking a simple pain killer medication such as paracetamol could relieve the symptoms
  • Skin manifestations (itchiness, rashes, hair loss)
  • Allergic reaction; shortness of breath, facial swelling
  • Blood; agranulocytosis (a condition where the level of white blood cell is lowered and failure to recognize this condition could lead to a more severe condition)
  • Hypothyroidism if taken in large amount and unsupervised

Agranulocytosis is a rare condition but a serious side effect caused by carbimazole and other drugs as well. The symptoms includes:

  • Fever with chills and rigors
  • Increased tendency to bleed and bruising
  • Sore throat
  • Unexplained muscle weakness and fatigue

If you are experiencing the condition mentioned above, please seek immediate medical attention for further evaluation and so that adjustment of dose or changing of medication can be done.

Other than that, there are some precautions that need to be taken into consideration of prescribing carbimazole to a patient and also the patient needs to be aware of his or her own condition. Some of the conditions are:

  • Pregnant, breastfeeding or trying to conceive
  • Having a blood or bone marrow disorder
  • Having a liver disease
  • History of inflamed pancreas (pancreatitis) before
  • Having any allergy to medicine
  • Taking any other medication including traditional medicine

The conditions above are important to be addressed so that carbimazole dosage can be adjusted or if it is not suitable, it can be substituted with another antithyroid medication. Other than that, some conditions may worsen and some medicine may have altered effects as carbimazole can interact with other medications. Therefore it is important to address the above issue mentioned.

It may take a while for a patient to see changes and improvements in their hyperthyroidism status as it depends on the thyroid level and how the patient’s body responds to carbimazole.

As a take home message, these are the general advice regarding carbimazole:

  • Consume it according to the prescription.
  • If you have any medical condition and allergies towards medications, let your doctor know about your condition.
  • If you are experiencing any symptoms after taking the medication, seek medical attention as soon as possible.
  • Keep it away from children, moisture and sunlight. Keep it in a safe place.