Thyroid and Antithyroid Drugs

NHSL Medicines Guidance
NHS Lanarkshire

Section Under Review

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Thyroid Hormones

Preferred list (P)

LEVOTHYROXINE

Antithyroid Drugs

Specialist initiation (S1)

CARBIMAZOLE

  • First choice

PROPYLTHIOURACIL

  • Second choice

PROPRANOLOL

NADOLOL

Prescribing Notes:

  • Radioactive iodine is increasingly used as first choice for thyrotoxicosis. Its efficacy may be compromised by prior antithyroid drug therapy. It is contra-indicated in pregnancy.
  • CARBIMAZOLE has rarely been associated with bone marrow suppression and treatment should be stopped promptly if there is clinical or laboratory evidence of neutropenia. Patients should be asked to report symptoms and signs suggestive of infection, especially sore throat. A white blood cell count should be performed if there is any clinical evidence of infection.
  • PROPYLTHIOURACIL may be an alternative for patients who suffer sensitivity reactions to CARBIMAZOLE. It may also be used in pregnancy under specialist supervision.
  • Beta blockade can be gradually withdrawn once hyperthyroidism is controlled (2 to 6 weeks), and the patient maintained on CARBIMAZOLE.

NHSL Joint Adult Formulary Key

To indicate the category of a formulary medicine, updated sections adopt the following key:

Preferred list (P): First-line formulary choices.

Total list (T): Alternative choices when preferred list options not effective/not tolerated, or not indicated.

Specialist initiation (S1): Specialist initiation, or on the advice of a Consultant or Specialist Practitioner in this therapeutic area. Continuation in primary care is acceptable.

Specialist use only (S2): Supply via hospital, Homecare Service or a hospital based prescription (HBP) for dispensing by community pharmacy. Not prescribed in primary care setting.

Editorial Information

Last reviewed: 31/01/2022

Next review date: 31/01/2025

Author(s): NHSL.

Version: Please refer to the introduction section for an explanation of the review dates above.

Approved By: ADTC

Reviewer name(s): ADTC.