Propylthiouracil (thiocarbamide) is an antithyroid drug. The drug is a common therapeutic choice for the following:
Propylthiouracil inhibits the production of new thyroid hormone in the thyroid gland. It acts by inhibiting the enzyme thyroid peroxidase, which usually functions to convert iodide to iodine molecule and incorporate the iodine molecule into amino acid tyrosine. Hence, DIT (diiodotyrosine) or MIT (monoiodotyrosine) does not get produced, which are the main constituents in the production of thyroxine (T4) and triiodothyronine (T3). Peripherally, it acts by inhibiting the conversion of T4 to T3. It has effects on the existing thyroid hormones stored in the thyroid gland or circulating in the blood.
The available propylthiouracil tablet has 50 mg of the drug, and storage should be at room temperature. Dosage is as follows:
Propylthiouracil and patient population groups:
Observed adverse reactions in laboratory animals:
Laboratory monitoring of thyroid function tests should take place while the patient is on PTU therapy. Prothrombin time also requires monitoring in patients who are also on warfarin therapy concomitantly.
A key component of PTU therapy is patient education and counseling. The patient should receive counsel to:
There is no information regarding the lethal dose (LD50), serum level concentration of PTU associated with symptoms of overdose, or the amount of single drug dose assumed to be causing overdose symptoms. Symptoms reported are nausea, vomiting, epigastric distress, headache, fever, and arthralgia. Patients are also at risk of developing ANCA associated vasculitis, agranulocytosis, or acute hepatic injury may occur. In the event of overdose, consider the possibility of drug interaction or abnormal pharmacokinetics in the patient. Patients may also develop symptoms of severe hypothyroidism. Patient treatment is supportive as there is no antidote available and also stop the drug.
All healthcare personnel: clinicians, nurses, and pharmacists should be aware of the indications and adverse effects profile of PTU and function collaboratively as an interprofessional team. The physicians should gather an appropriate medication history and consider drug interactions with PTU. All the healthcare personnel should educate the patients regarding medication-related adverse effects and the need for regular close surveillance. Patient education is a crucial aspect. Educate the patients that if there are any new symptoms, PTU should be discontinued immediately. Moreover, depending on the severity of symptoms, patients need to contact the prescribing physician or go to the emergency department.
Clinicians will make the decision to dose PTU when appropriate. The pharmacist should verify all dosing by indications, perform medication reconciliation, and report back any discrepancies. Nursing will handle administration for the in-patients, and serve as an initial point of contact for outpatients, as well as being able to monitor treatment effectiveness. All healthcare personnel should monitor for adverse reactions as well as medication compliance and therapy effectiveness.
PTU therapy requires an interprofessional team approach, including primary care physicians, specialists, specialty-trained nurses, and pharmacists, all working together across disciplines to achieve desired patient results. [Level V]
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