THE PHARMACOKINETICS OF 2 DOSES (50 µG AND 100 µG) LEVOTHYROXINE TREATMENT IN ATHYREOTIC PATIENTS


Karunrat Tewthanom, Walaya Jongjaroenprasert

Abstract


Objective: Hypothyroid has still be a problem in Thailand. Lack of pharmacokinetics information of levothyroxine in athyreotic patients for modify dosing. Therefore, the aim of this study was to investigate the pharmacokinetic parameters of 2 doses of levothyroxine(50 mg and 100 mg) in such group of patients.

Methods: The 24 athyreotic patients were recruited and randomly assigned to receive 50 mg or 100 mg of levothyroxine. The pharmacokinetic parameters (Cmax, Tmax, AUC0-8, ke, T1/2 and Vd) of FT4 and TSH were calculated by the non-compartment model. The parameters of 2 doses were compared.

Results: From the results found that, by monitoring FT4, there was no statistically significant difference (p>0.05) of almost all pharmacokinetic parameters between 2 doses except Cmax which has significant greater in 100 mg of levothyroxine. While all pharmacokinetics parameters of TSH were not statistically significant difference. The use of non-compartment model seems appropriate for calculation of pharmacokinetic parameters of FT4 (R2 = 0.81) while it has poor predictive capacity in terms of TSH (R2 = 0.24).

Conclusion: In conclusion, administration of 50 mg and 100 mg of levothyroxine to athyreotic patients have similar pharmacokinetic in term of FT4(non-significant different in Tmax, AUC) and TSH. Further study of these parameters in more subjects is needed.


Keywords


Pharmacokinetics, Athyreotic patients, Levothyroxine

| PDF | HTML |

References


Hollowell JG, Staehling NW, Flanders WD, Hannon WH, Gunter EW, CA S. Serum TSH, T, and thyroid antibodies in the united states population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab 2002;87:489-99.

Vanderpump MP, Tunbridge WM, French JM, Appleton D, Bates DFC. The incidence of thyroid disorders in the community: a twenty-year follow-up of the whickham survey. Clin Endocrinol (Oxf) 1995;43:55-68.

Tunbridge WM, Evered DC, Hall R, Appleton D, Brewis M, Clark F. The spectrum of thyroid disease in a community: the Whickham survey. Clin Endocrinol (Oxf) 1977;7:481-93.

AACE Thyroid Task Force. American association of clinical endocrinologist medical guidelines for clinical practice for evaluation and treatment of hyperthyroidism and hypothyroidism. Endocrine Practice 2002;8:457-69.

Thyroid Carcinoma Task Force. AACE/AAES medical/surgical guidelines for clinical practice: management of thyroid carcinoma. Endocrine Practice 2001;7:213-20.

Annemieke Roos, Suzanne P Linn-Rasker, Ron T van Domburg, Jan P Tijssen, Arie Berghout. The starting dose of levothyroxine in primary hypothyroidism treatment. A prospective, randomised, double-blind trial. Arch Intern Med 2005;165:1714-20.

Srinivas V, Oyibo SO. Levothyroxine pseudo malabsorption and thyroxine absorption testing with use of high-dose levothyroxine: case report and discussion. Endocr Pract 2010;16:1012-5.

Blakesley V, Awni W, Locke C, Ludden T, Granneman GR, Braverman LE. Are bioequivalence studies of levothyroxine sodium formulations in euthyroid volunteers reliable? Thyroid 2004;14:191-200.

Eduardo Abib Junior, J osé Pedrazzoli Junior, lf duarte, Ps marques, DP tosetti, Sf souza, et al. Levothyroxine bioequivalence study: determination in healthy volunteers by microparticle enzyme immunoassay. Global J Med Res 2010;10:58-63.

Soldin OP, Soldin SJ, Vinks AA, Younis I, Landy HJ. Longitudinal comparison of thyroxine pharmacokinetics between pregnant and nonpregnant women: a stable-isotope study. Ther Drug Monit 2010;32:767-73.

Jari J Lilja, Kalevi Laitinen, Neuvonen PJ. Effects of grapefruit juice on the absorption of levothyroxine. Br J Clin Pharmacol 2005;60:337-41.




About this article

Title

THE PHARMACOKINETICS OF 2 DOSES (50 µG AND 100 µG) LEVOTHYROXINE TREATMENT IN ATHYREOTIC PATIENTS

Keywords

Pharmacokinetics, Athyreotic patients, Levothyroxine

Date

01-10-2016

Additional Links

Manuscript Submission

Journal

International Journal of Applied Pharmaceutics
Vol 8, Issue 4, 2016 Page: 66-68

Online ISSN

0975-7058

Statistics

27 Views | 39 Downloads

Authors & Affiliations

Karunrat Tewthanom
Department of Pharmacy, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, 73000, Thailand
Thailand

Walaya Jongjaroenprasert
Department of Medicine, Faculty of Medicine, Ramathibodi hospital, Mahidol University, Bangkok, 10400, Thailand
Thailand


Refbacks

  • There are currently no refbacks.