Adverse reactions

The thionamide drugs are all liable to cause minor and major adverse effects. Minor are rash, urticaria, arthralgia, fever, anorexia, nausea, abnormalities of taste and smell. Major are agranulocytosis, thrombocytopenia, acute hepatic necrosis, cholestatic hepatitis, lupus-like syndrome, vasculitis.

1 Use of a thionamide during the week before and after radioiodine therapy may impair the response to radiation (Velkeniers B et al 1988 Lancet 1:1127) (see Mode of action of thionamides, above).

Blood disorders (<3/10 000 patient years) are most common in the first 2 months of treatment. Routine leucocyte counts have been advocated in order to detect blood dyscrasia before symptoms develop; but agranulocytosis may be so acute that the counts give no warning. Patients must be advised to stop the drug and have a leucocyte count performed if symptoms of a sore throat, fever, bruising or mouth ulcers develop. Any suggestion of anaemia should be investigated. Cross allergy between the drugs occurs sometimes, but must not be assumed for agranulocytosis. Treatment of agranulocytosis consists of drug withdrawal, admission to hospital, and administration of broad-spectrum antibimi-crobials plus granulocyte colony stimulating factor (where available).

Pregnancy. If a pregnant woman has hyperthyroidism (2/1000 pregnancies) she should be treated with the smallest possible amount of these drugs because they cross the placenta; with over-treatment fetal goitre occurs. Surgery in the second trimester may be preferred to continued drug therapy

During breast feeding, propylthiouracil is the treatment of choice because little passes into breast milk.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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