Nothing to add - except to ask if anyone has ever had Rifampicin? And did they notice anything from taking it?
(Rifampin is another name for rifampicin which is an antibiotic.)
PLoS One. 2017 Jan 12;12(1):e0169775. doi: 10.1371/journal.pone.0169775. eCollection 2017.
Effect of Rifampin on Thyroid Function Test in Patients on Levothyroxine Medication.
Kim HI1, Kim TH1, Kim H1, Kim YN1, Jang HW2, Chung JH1, Moon SM3, Jhun BW3, Lee H3, Koh WJ3, Kim SW1.
1Division of Endocrinology & Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
2Department of Medical Education, Sungkyunkwan University School of Medicine, Seoul, South Korea.
3Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Levothyroxine (LT4) and rifampin (RIF) are sometimes used together; however, no clinical studies have assessed the effects of these drugs on thyroid function or the need to adjust LT4 dose.
We retrospectively reviewed the records of 71 Korean patients who started RIF during LT4 treatment. Clinically relevant cases that required dose adjustment according to the American Thyroid Association (ATA)/American Association of Clinical Endocrinologists (AACE) guidelines were identified, and risk factors of increased LT4 dose were analyzed.
After administering RIF, median serum thyroid-stimulating hormone (TSH) level (2.58 mIU/L, interquartile range [IQR] 0.21-7.44) was significantly higher than that before RIF (0.25 mIU/L, IQR, 0.03-2.62; P < 0.001). An increased LT4 dose was required for 50% of patients in the TSH suppression group for thyroid cancer and 26% of patients in the replacement group for hypothyroidism. Risk factor analysis showed that remaining thyroid gland (odds ratio [OR] 9.207, P = 0.002), the time interval between starting RIF and TSH measurement (OR 1.043, P = 0.019), and baseline LT4 dose per kg body weight (OR 0.364, P = 0.011) were clinically relevant variables.
In patients receiving LT4, serum thyroid function test should be performed after starting RIF treatment. For patients with no remnant thyroid gland and those receiving a lower LT4 dose, close observation is needed when starting RIF and TB medication.
Full paper freely available here: