Comparative Interchangeability Assessment of Commercially Available Marketed Brands of Levothyroxine by Serum Thyroid-Stimulating Hormones in Pakistan

Abstract

Background: Oral levothyroxine (LT 4) is the standard recommended treatment of hypothyroidism, and multiple brands are available on the market. Comparative interchangeability through serum thyroid-stimulating hormones is still debatable due to patient compliance. This study aimed to assess the potential clinical interchangeability of several brands of LT4 prompted by a lack of available brands by analyzing the thyroid-stimulating hormone (TSH) levels in patients utilizing different LT4 brands.

Materials and methods: Randomized cross observational research recruited 168 individuals with primary hypothyroidism utilizing a designated endocrinology outpatient department. Brands were chosen from community and hospital pharmacies. The study comprised four groups: a parent generic and three distinct brands (two global and one local), employing two-sample t-tests and analysis of variance.

Results: Of the 168 patients, 69 were male (41.1%) and 99 were female (58.9%). The data collection indicated that the 36-45 age group was overrepresented, with 54 persons (32.1%) of the overall sample population. The age segment of 26 to 35 appeared as the second most prevalent demographic with hypothyroidism. Thyroxine was the predominant brand among all others; 75.59% of patients utilized thyroxine. Edema occurred in 55 cases (32.7%), and dry skin in 77 cases (45.8%), representing the most prevalent adverse effects across all brands.

Conclusion: Interchangeability of all groups, either patent or generic drugs or multinational and local pharmaceutical companies, was equivalent as per serum TSH, and there was no difference between them (shortage and storage are the constant factors of all the groups).