What is the most likely treatment advised for thyrotoxicosis in a patient keen to become pregnant?

In the context of managing thyrotoxicosis in patients who are planning to become pregnant, propylthiouracil (PTU) is often preferred, especially in the first trimester. PTU is an antithyroid medication that is less likely to cross the placenta and cause fetal complications compared to other options. It has a favorable safety profile during early pregnancy and minimizes risks to both the mother and developing fetus.

Carbimazole, while effective in treating hyperthyroidism, poses a higher risk of teratogenic effects if administered during early pregnancy, which can impact the developing fetus. Therefore, it is generally advised to use PTU during this sensitive period.

Starting or continuing treatment with a combination of antithyroid drugs and thyroxine is not a standard practice for managing thyrotoxicosis. Thyroidectomy could be considered in patients with contraindications to medical therapy or those with large goiters, but it is not the preferred first-line treatment for a patient aiming to conceive.

Thus, PTU becomes the most appropriate choice for managing thyrotoxicosis in a patient keen on becoming pregnant, ensuring both effective management of the hyperthyroid condition while minimizing fetal risks.