Fichas
Thyroid Hormones
Fichas del conjunto (4)
- 1Give eg's of & indications for thyroid hormones.• eg's: levothyroxine, liothyronine
Common indications:
• Primary hypothyroidism
• Hypothyroidism secondary to hypopituitarism - 2MOA of thyroid hormones.The thyroid gland produces thyroxine (T4), which is converted to the more active triiodothyronine (T3) in target tissues. Thyroid hormones regulate metabolism & growth. Deficiency of these hormones causes hypothyroidism, with clinical features including lethargy, weight gain, constipation & slowing of mental processes. Hypothyroidism is Rx'd by long-term replacement of thyroid hormones, most usually as levothyroxine (synthetic T4). Liothyronine (synthetic T3) has a shorter half-life & quicker onset (a few hours) & offset (24–48 hrs) of action than levothyroxine. It is therefore reserved for emergency Rx of severe or acute hypothyroidism.
- 3SE's of thyroid hormones.• GI - diarrhoea, vomiting, weight loss
• Cardiac - palpitations, arrhythmias, angina
• Neurological - tremor, restlessness, insomnia - 4CI's, cautions, & important interactions of thyroid hormones.CI's:
• None
Cautions:
• Coronary artery DS - replacement should be started cautiously at a low dose & with careful monitoring
• Hypopituitarism - corticosteroid Rx must be initiated before thyroid hormone replacement to avoid precipitating an Addisonian crisis
Important interactions:
As GI absorption of levothyroxine is reduced by antacids, calcium or iron salts, administration of these drugs needs to be separated by about 4 hrs. An ^in levothyroxine dose may be required in pt's taking cytochrome P450 inducers, e.g. phenytoin, carbamazepine. Levothyroxine-induced changes in metabolism can ^insulin or oral hypoglycaemic requirements in DM & enhance the effects of warfarin.
Información
- Descripción
- Top 100 drugs.
- Creado por
- Andrew Street · ene 2017
- Actualizado
- 4 ene 2017
- Visitas
- 32
- Etiquetas
- Valoración