Thioamide

Thioamides are a group of drugs used to control thyrotoxicosis. Thioamides are also a group of organic compounds that share a common functional group with the general structure R¹-CS-NR²R³.

Mechanism of action

They inhibit the enzime peroxidase in the thyroid, reducing the synthesis of t3 and t4; block uptake of iodotyrosines from the colloid. They also block iodine release from peripheral hormone. Maximum effects occur only after a month since hormone depletion is caused by reduced synthesis, which is a slow process.

Adverse effects

• Penetrates the placental barrier, thus caution is advised when used during pregnancy.

In some 10% of pacients:

• Agranulocytosis a dangerous side-effect.
• Skin eruptions, such as macules and papules.
• Urticaria
• Dermatitis
• Fever
• Arthralgia

Members of the group

• Methimazole
• Carbimazole converted in vivo to methymazol
• Propylthiouracil