Endocrine

Overactive thyroid (hyperthyroidism)

Also called: overactive thyroid, thyrotoxicosis, hyperthyroid, Graves' disease, toxic goitre

An overactive thyroid (hyperthyroidism) means the thyroid gland in the neck makes too much thyroid hormone. This speeds up the body, causing weight loss, a fast heartbeat, shaking and feeling hot. A blood test finds it, and medicines, radioactive iodine or surgery treat it well.

General health information for Pakistan. It does not give doses or brand advice. If you are worried, or symptoms are severe, see a doctor. When to see a doctor

Overview

The thyroid is a small gland at the front of the neck. It makes hormones that control how fast the body uses energy, as well as the heart rate and body temperature. In hyperthyroidism the gland makes more hormone than the body needs, so many body systems run too fast. Doctors also use the word thyrotoxicosis (too much thyroid hormone in the blood, from any cause).

The most common cause is Graves' disease, an autoimmune condition (the body's defence system attacks its own tissue). Antibodies push the thyroid to make extra hormone. Other causes are lumps (nodules) in the thyroid that make hormone on their own, inflammation of the thyroid (thyroiditis), and some medicines. The condition is much more common in women than in men, and it often starts between the ages of 20 and 40.

Hyperthyroidism is usually very treatable. Medicines can calm the symptoms and lower hormone production. Some people need a longer-lasting treatment such as radioactive iodine or an operation to remove part or all of the gland. After these, many people need a daily thyroid hormone tablet for life. Without treatment, an overactive thyroid can harm the heart, bones, eyes and, in women, pregnancy.

In Pakistan: what studies show

Hospital studies in Peshawar, Lahore and Karachi all found that Graves' disease causes about half of overactive thyroid cases (50.4%, 50.9% and 53%). In one Punjab district 28.7% of residents had a goitre, and in 2018 79.6% of households nationally had properly iodised salt.

In one Peshawar teaching hospital study of 119 patients with thyrotoxicosis (2022-2023), Graves' disease was the cause in 50.4%.^[1] (cross-sectional, data December 2022 - May 2023)
In the same Peshawar hospital study, 28.6% of patients (34 of 119) were treated with radioactive iodine.^[1] (cross-sectional, data December 2022 - May 2023)
Among 112 patients given radioactive iodine at one Lahore hospital (2008-2018), 50.9% had Graves' disease and 32.1% had a toxic multinodular goitre.^[2] (retrospective cohort, data June 2008 - May 2018)
In the same Lahore study, 75% of patients (84 of 112) were cured within one year of radioactive iodine treatment.^[2] (retrospective cohort, data June 2008 - May 2018)
An older study of 507 patients at one Karachi endocrine clinic (2007-2011) found Graves' disease in 53%, with toxic multinodular goitre next.^[3] (retrospective chart review, data April 2007 - January 2011)
In a community survey of 2,335 residents of Pakpattan district, Punjab, 28.7% had a goitre that could be felt.^[4] (cross-sectional community survey, data not stated (published 2015))
In the same Pakpattan survey, 48% of people with a goitre who had a thyroid blood test (89 of 185) had an overactive thyroid.^[4] (cross-sectional community survey, data not stated (published 2015))
In the 2018 National Nutrition Survey of 100,304 households, 79.6% had salt with enough iodine, the main way to prevent iodine-deficiency goitre.^[5] (national survey, data April 2018 - January 2019)

What we do not know yet: There is no national survey of how many Pakistanis have an overactive thyroid; the data come from single hospitals and one Punjab district, so the 50.4%, 50.9% and 53% Graves' shares describe hospital patients, not the whole country. The goitre survey did not state its collection years, the Karachi data are from 2007-2011, and we found no Pakistan guideline for treating hyperthyroidism.

Pakistan studies cited

Iqbal F, Ghaffar T, Shah MA, et al. Probing the underlying causes of Thyrotoxicosis and its applied significance: a comprehensive evaluation. Khyber Medical University Journal 2024;16(1):77-82. doi:10.35845/kmuj.2024.23383. Open source
Alvi AM, Azmat U, Shafiq W, et al. Efficacy of Radioiodine Therapy in Patients With Primary Hyperthyroidism: An Institutional Review From Pakistan. Cureus 2022. doi:10.7759/cureus.24992. Open source
Ahsan T, Banu Z, Jabeen R, et al. Clinical spectrum and various forms of thyrotoxcosis in endocrine clinic of Jinnah Postgraduate Medical Centre. Journal of the Pakistan Medical Association (JPMA) 2013;63(3):354. Open source
Jawa A, Jawad A, Riaz SH, et al. Turmeric use is associated with reduced goitrogenesis: Thyroid disorder prevalence in Pakistan (THYPAK) study. Indian Journal of Endocrinology and Metabolism 2015;19(3):347-350. doi:10.4103/2230-8210.152768. PMID 25932388. Open source
Government of Pakistan, UNICEF National Nutrition Survey 2018 - Key Findings Report. Government of Pakistan and UNICEF 2019. Open source

Symptoms

Feeling nervous, anxious, irritable or restless, with mood swings
Losing weight even though you are eating more (a few people gain weight)
A fast, pounding or irregular heartbeat (palpitations)
Shaking or trembling hands (tremor) and muscle twitching
Feeling too hot, sweating a lot and having warm, moist skin
Tiredness, weak muscles (especially in the thighs and shoulders) and trouble sleeping
Going to the toilet more often or having loose stools (diarrhoea)
A swelling at the front of the neck from an enlarged thyroid (goitre)
Lighter or irregular periods, and thinning hair
Gritty, red or bulging eyes, or double vision, in some people with Graves' disease

Causes and risk factors

Causes

Graves' disease: the immune system makes antibodies that switch the thyroid on all the time. It causes about four in five cases of overactive thyroid in the UK.
Toxic multinodular goitre: several lumps in the thyroid make too much hormone. It is seen more in older adults and in places where people get too little iodine.
Toxic adenoma: a single overactive lump (nodule) in the thyroid
Thyroiditis (inflammation of the thyroid) after a viral infection, after pregnancy or from certain medicines, which lets stored hormone leak out; this type often settles by itself
Medicines such as amiodarone (a heart rhythm medicine) or lithium, very large amounts of iodine (for example from X-ray contrast dye), or taking too much thyroid hormone tablet

What makes it more likely

Being female
Being a young or middle-aged adult (Graves' disease often starts between 20 and 40)
A family history of thyroid disease (genes play a part)
Smoking
Getting too little or too much iodine in the diet
Taking medicines that can affect the thyroid, such as amiodarone or lithium
Recently having a baby (thyroiditis can follow pregnancy)

Complications

If it is not treated or is poorly controlled, an overactive thyroid can cause serious problems. The heart may beat irregularly (atrial fibrillation), which raises the risk of stroke and heart failure. The bones can thin (osteoporosis), making fractures more likely. Graves' disease can affect the eyes, causing irritation, double vision, bulging eyes and, rarely, loss of sight. In pregnancy, it raises the risk of pre-eclampsia, early birth and miscarriage. Rarely, symptoms suddenly flare into a thyroid storm, with fever, confusion and a racing heart; this is life-threatening and needs hospital care. Antithyroid medicines can rarely cause a very low white blood cell count (agranulocytosis) or liver damage.

When to see a doctor

Confusion, extreme agitation, fainting or becoming drowsy, with a high fever: this may be a thyroid storm, so go to the emergency department at once
A very fast or irregular heartbeat with chest pain, breathlessness or dizziness: get emergency help
Fever, sore throat or mouth infection while taking an antithyroid medicine: stop the medicine and contact your doctor straight away for a blood count
Yellow skin or eyes, dark urine, itchy rash or pain in the belly while taking an antithyroid medicine: contact your doctor urgently
Eye pain, sudden blurred or double vision, or loss of vision
A fast-growing swelling in the neck that makes it hard to breathe or swallow
Symptoms of an overactive thyroid during pregnancy or when planning a pregnancy

Diagnosis

Hyperthyroidism is found with a blood test. The first test is usually TSH (thyroid-stimulating hormone, the signal from the brain to the thyroid). In an overactive thyroid TSH is low. If it is low, the laboratory also measures free T4 and T3, the thyroid hormones themselves. When TSH is low but T4 and T3 are normal, it is called subclinical (mild) hyperthyroidism, which may only need repeat tests. Tell your doctor if you take biotin supplements, because high amounts can upset thyroid results.

The next step is to find the cause. A blood test for TSH receptor antibodies (TRAb) can confirm Graves' disease. If this is negative, a thyroid scan with a small radioactive tracer shows whether there are hot nodules or thyroiditis. A neck ultrasound is used if a lump can be felt. Scans with radioactive tracers are not done in pregnancy or breastfeeding.

Treatment

Calm the symptoms: a beta blocker eases a fast heartbeat, shaking, sweating and anxiety while the hormone level comes down. A calcium-channel blocker is an option if a beta blocker is not suitable.
Lower hormone production with an antithyroid medicine. Carbimazole is the usual first choice; propylthiouracil is used mainly in early pregnancy, when planning a pregnancy, or after a reaction to carbimazole. For Graves' disease it is usually taken for about 12 to 18 months, and your doctor decides the dose.
Have blood tests regularly so the doctor can adjust the treatment. Some people take an antithyroid medicine together with thyroid hormone (block and replace); others take one medicine adjusted over time (titration).
If Graves' disease comes back, or remission is unlikely, a specialist may advise radioactive iodine, which shrinks the overactive gland over a few months. It is not given in pregnancy or to people with active thyroid eye disease.
Surgery to remove all or part of the thyroid is chosen for a large goitre pressing on the windpipe or food pipe, a suspected cancer, or when other treatments are not suitable.
After radioactive iodine or surgery, the thyroid often becomes underactive, so many people need a daily thyroid hormone tablet for life, with yearly checks.
Mild thyroiditis often settles on its own and may only need a beta blocker for comfort.

Medicines in Pakistan

Medicines a doctor may use, by group. Each link opens our page for that medicine, with every brand and its official DRAP price. Your doctor decides which medicine and dose are right for you.

Group	Role	Medicines
Antithyroid medicines	lower the amount of hormone the thyroid makes; carbimazole is usually first, propylthiouracil mainly in early pregnancy or if carbimazole is not tolerated	Carbimazole (2 brands), Propylthiouracil (1 brand)
Beta blockers	quickly ease a fast heartbeat, tremor, sweating and anxiety until hormone levels fall; propranolol is preferred in pregnancy and breastfeeding	Propranolol (17 brands), Atenolol (27 brands)
Calcium-channel blockers	slow a fast heartbeat when a beta blocker cannot be used, for example in some people with asthma	Verapamil (14 brands)
Thyroid hormone replacement	replaces hormone after radioactive iodine or surgery if the thyroid becomes underactive, or as part of a block-and-replace plan	Levothyroxine sodium (17 brands)

Also used (not yet in our price list): Methimazole (thiamazole), an antithyroid medicine widely used outside the UK, Radioactive iodine (radioiodine, iodine-131), given in hospital

Self-care and prevention

Self-care

Take your thyroid medicine exactly as prescribed and do not stop it without talking to your doctor
Go for every follow-up blood test, because the treatment is adjusted from the results
Learn the warning signs of a low white cell count (fever, sore throat, mouth ulcers) and liver trouble (yellow eyes, dark urine) and act on them quickly
Stop smoking: smoking makes Graves' disease less likely to settle with medicine and can worsen eye problems
Tell your doctor if you are pregnant or planning a pregnancy, as the choice of medicine changes
Do not take iodine supplements, thyroid tablets or biotin without asking your doctor or pharmacist

Prevention

Most cases, such as Graves' disease, cannot be prevented, so the aim is to find and treat them early
Do not smoke
Avoid taking iodine supplements or thyroid hormone tablets unless a doctor has advised them
If you take amiodarone or lithium, tell your doctor about any symptoms of an overactive thyroid
After treatment, keep up regular thyroid blood tests so a relapse or an underactive thyroid is picked up early

Common questions

Can hyperthyroidism be cured?

Yes, in many cases. Some people with Graves' disease go into remission after a course of antithyroid medicine, but it can come back. Radioactive iodine and surgery give a longer-lasting fix, although afterwards many people need a thyroid hormone tablet for life.

What is the difference between Graves' disease and hyperthyroidism?

Hyperthyroidism means the thyroid is making too much hormone. Graves' disease is the most common cause of it. In Graves' disease the immune system makes antibodies that over-stimulate the thyroid, and it can also affect the eyes.

Why must I report a sore throat while taking carbimazole?

Antithyroid medicines can rarely cause a sharp drop in white blood cells, which fight infection. A fever, sore throat or mouth ulcers can be the first sign. Stop the medicine and contact your doctor straight away for a blood count; if the count is low, the medicine must not be restarted.

Is radioactive iodine safe?

It is a long-used, effective treatment that NICE suggests as a first choice for many adults with Graves' disease or toxic nodules. It is not given in pregnancy or when trying for a baby soon, and it can worsen active thyroid eye disease. It often leaves the thyroid underactive, which is treated with a daily hormone tablet.

Can I get pregnant if I have an overactive thyroid?

Yes, but plan it with your doctor. Uncontrolled hyperthyroidism raises the risk of pre-eclampsia, early birth and miscarriage. Your doctor may change your medicine before or during early pregnancy.

Sources

NICE. Thyroid disease: assessment and management (NG145) (2023).
NICE. Thyroid disease: assessment and management (NG145) - Overview (2025).
American Thyroid Association (Thyroid 2016;26(10)). 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis (2016).
NHS. Overactive thyroid (hyperthyroidism) - NHS (2023).
MedlinePlus (US National Library of Medicine). Hyperthyroidism: MedlinePlus Medical Encyclopedia (2024).
StatPearls (NCBI Bookshelf). Hyperthyroidism - StatPearls - NCBI Bookshelf (2023).
Khyber Medical University Journal (Iqbal F, Ghaffar T, Shah MA, Ahmad R). Probing the underlying causes of Thyrotoxicosis and its applied significance: a comprehensive evaluation (2024).

Prepared from the sources listed below by the MedInfoBase team. Last reviewed 16 October 2026. This page is general health information, not medical advice. It gives no doses and does not replace a doctor: talk to your doctor or pharmacist before starting, stopping or changing any medicine. How we write and check our pages.

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