Propylthiouracil oral
- Drugs List
- Therapeutic Indications
- Dosage
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Tablets containing propylthiouracil.
Drugs List
Therapeutic Indications
Uses
Hyperthyroidism
Thyrotoxic crisis
Dosage
Adults
Management of Hyperthyroidism
Initially 300mg to 600mg once daily or in divided doses until the patient becomes euthyroid.
Once condition is controlled (usually after 1 to 2 months), reduce dose to 50mg to 150mg daily and continue for 1 to 2 years.
Preparation for surgery
Initially 300mg to 600mg once daily or in divided doses until the patient becomes euthyroid.
In Preparation for Radioactive Iodine Therapy
As for the management of hyperthyroidism, for several weeks prior to radioiodine treatment. Withdraw treatment 2 to 4 days before iodine treatment.
Thyrotoxic crisis
200mg every 4 to 6 hours for the first 24 hours. Reduce the dose as the condition improves.
Children
Treatment of Juvenile Hyperthyroidism
Children aged over 10 years: Initially 150mg to 300mg once daily or in divided doses.
Children aged 6 to 10 years: Initially 50mg to 150mg once daily or in divided doses.
Maintenance dose is determined by the patient's response.
The following alternative dosing schedule may be suitable:
Children aged 12 to 18 years: 100mg three times a day until euthyroid (usually 4 to 8 weeks), then gradually reduce to a maintenance dose of 30 to 60% of the initial dose. Higher initial doses may be required in thyrotoxic crisis.
Children aged 6 to 12 years: 50mg three times a day until euthyroid (usually 4 to 8 weeks), then gradually reduce to a maintenance dose of 30 to 60% of the initial dose. Higher initial doses may be required in thyrotoxic crisis.
Children aged 1 to 6 years (unlicensed): 25mg three times a day until euthyroid (usually 4 to 8 weeks), then gradually reduce to a maintenance dose of 30 to 60% of the initial dose. Higher initial doses may be required in thyrotoxic crisis.
Children aged 1 month to 1 year (unlicensed): 2.5mg/kg three times a day until euthyroid (usually 4 to 8 weeks), then gradually reduce to a maintenance dose of 30 to 60% of the initial dose. Higher initial doses may be required in thyrotoxic crisis.
Neonates
Treatment of Hyperthyroidism
5 to 10mg/kg daily.
Patients with Renal Impairment
Glomerular filtration rate (GFR) 10 to 50ml/minute: Reduce dose by 25%.
Glomerular filtration rate (GFR) below 10ml/minute: Reduce dose by 50%.
Contraindications
None known
Precautions and Warnings
Children under 6 years
Breastfeeding
Galactosaemia
Glucose-galactose malabsorption syndrome
Hepatic impairment
Lactose intolerance
Pregnancy
Renal impairment - glomerular filtration rate below 50ml/minute
Reduce dose in patients with glomerular filtration rate below 50ml/min
Reduce dose in patients with hepatic impairment
Not all available brands are licensed for all age groups
Not all available brands are licensed for all indications
Some formulations contain lactose
Monitor prothrombin times
Monitor thyroid function regularly
Perform full blood count if signs of infection occur
Advise patient to report any symptoms of infections especially sore throats
Advise patients to report signs of hepatic damage (malaise, jaundice etc.)
Discontinue if clinical/laboratory evidence of neutropenia
Discontinue if significant/persistent hepatic function abnormalities occur
Patients should report signs of fever, mouth ulcers, rashes or sore throat as it could be an indication of agranulocytosis, a rare but serious adverse effect of propylthiouracil. Risk factors include patients being over the age of 40 years and receiving larger doses of propylthiouracil and being used in patients receiving other drugs known to cause agranulocytosis. Agranulocytosis usually occurs within the first two months of treatment and propylthiouracil should be stopped if this occurs.
Cases of severe hepatic adverse reactions have been reported in adults and children, including fatal cases or cases needing liver transplant. Most cases occurred within 6 months of starting the treatment.
Pregnancy and Lactation
Pregnancy
Use propylthiouracil with caution during pregnancy.
Propylthiouracil crosses the placenta and in high doses may cause foetal goitre and hypothyroidism, therefore the lowest possible dose should be given and thyroid function monitored every 4 to 6 weeks to maintain optimum control.
Briggs and Schaefer state the thyrostatic agent of choice during pregnancy is propylthiouracil. No morphologic developmental disturbances have been observed, and no intellectual or physical development is affected. Briggs further outlines that any effect on the foetus is usually transient, passing a few days post parturition.
Schaefer states that screening of thyroid parameters of the newborn is absolutely necessary. A second evaluation of the thyroid status should be performed 2 weeks after birth in the case of intrauterine exposure.
Lactation
Use propylthiouracil with caution during breastfeeding.
Propylthiouracil is secreted in breast milk but this does not preclude breast feeding as neonatal thyroid function is unlikely to be affected by the dose transferred.
Side Effects
Acute hepatic necrosis (sometimes fatal)
Agranulocytosis
Alopecia
Anti-neutrophil cytoplasmic antibodies (ANCA)
Aplastic anaemia
Arthralgia
Bleeding
Chills
Cholestatic jaundice
Cutaneous vasculitis
Darkening of urine
Diarrhoea
Drug fever
Epigastric distress
Fever
Fulminant hepatic necrosis
Headache
Hepatic encephalopathy
Hepatic failure
Hepatitis with or without jaundice
Hepatocellular hepatitis
Hepatotoxicity
Hypoprothrombinaemia
Interstitial pneumonitis
Itching
Jaundice
Leucopenia (reversible)
Lupus erythematosus-like syndrome
Mouth ulcers
Myalgia
Nausea
Nephritis
Oedema
Paraesthesia
Periarteritis
Polymyositis
Pruritus
Rash
Severe hepatic reactions
Skin pigmentation changes
Sore throat
Taste disturbances
Thrombocytopenia
Urticaria
Vomiting
Yellow discolouration of skin
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last full review date: March 2014
Reference Sources
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia. Medications and Mothers' Milk, 14th Edition (2010) Hale, T. Hale Publishing, Amarillo, Texas.
Summary of Product Characteristics: Propylthiouracil 25mg Tablets. Macleods Pharma UK Limited. Revised February 2021.
Summary of Product Characteristics: Propylthiouracil tablets BP 50mg. RPH Pharmaceuticals AB. Revised January 2021.
Summary of Product Characteristics: Propylthiouracil 50mg tablets. Wockhardt UK Ltd. Revised November 2015.
Summary of Product Characteristics: Propylthiouracil 100mg Tablets. Macleods Pharma UK Limited. Revised February 2021.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 10 November 2021.
Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content
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