High thyroid hormone levels, or hyperthyroidism, is a condition where the thyroid gland in the body makes and releases too much thyroid hormone. People who have high thyroid hormone levels may experience fast heartbeats, weight loss, feel warm all the time and become more irritable. Propylthiouracil works by reducing the amount of thyroid hormone made.
If you forget to take a dose, take it as soon as you remember if it is not close to the next dose. Otherwise, you should skip the dose and take the next dose at the usual time. Do not take two doses together to make up for the missed dose.
Inform your healthcare professional if:
If you have any question about this medication, please discuss with your healthcare professional.
Let your healthcare professional know if you are taking, or planning to take any other herbal products, supplements (e.g. containing iodine) or medications.
Like all medications, this medication may cause some possible side effects but not everyone experiences them. Consult your healthcare professional if any of these side effects lasts more than a few days or become severe and bothersome.
The symptoms of a drug allergy include one or more of the following:
You can also find out about drug allergies by watching these videos:
They are available in English, 中文, Melayu and தமிழ்: Drug Allergies
In rare cases, Propylthiouracil:
If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.
Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.
Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.
Disclaimers
Please take note that the above is not a complete list of all possible side-effects. If you have any concerns about your medication or if you have other side-effects that you think are caused by this medication, please consult your doctor or pharmacist. If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.
This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (NHG Health, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.
Last Updated on June 2026
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