Why is Qsymia (phentermine and topiramate) contraindicated in patients with Graves' disease?

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Last updated: May 28, 2025View editorial policy

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From the Guidelines

Qsymia is contraindicated in patients with Graves' disease due to its phentermine component, which is a sympathomimetic amine that can worsen hyperthyroidism. Patients with Graves' disease already have excessive thyroid hormone production, causing increased heart rate, blood pressure, and metabolic rate. Adding phentermine could dangerously amplify these effects, potentially leading to severe cardiovascular complications such as tachycardia, hypertensive crisis, arrhythmias, or even thyroid storm. The topiramate component of Qsymia may also complicate thyroid function monitoring.

Key Considerations

  • According to the study 1, phentermine-topiramate ER should be avoided in patients with untreated hyperthyroidism due to concerns for arrhythmias and seizures.
  • The study 1 also advises caution and avoidance of phentermine in patients with a history of cardiovascular disease or uncontrolled hypertension, which can be exacerbated by Graves' disease.
  • Patients with Graves' disease should instead work with their healthcare provider to explore alternative weight management options that don't include sympathomimetic medications.

Alternative Weight Management Options

  • It's essential that any weight management strategy for these patients prioritizes thyroid disease control first, with careful consideration of medication interactions and cardiovascular safety.
  • Healthcare providers should consider the potential benefits and risks of alternative weight management options, such as lifestyle modifications or other medications, in patients with Graves' disease.

From the Research

Qsymia Contraindication with Graves' Disease

  • The provided studies do not directly address why Qsymia is contraindicated with Graves' disease 2, 3, 4, 5, 6.
  • However, it can be inferred that the interaction between Qsymia and Graves' disease may be related to the effects of Qsymia on the thyroid gland or the potential for exacerbating hyperthyroidism symptoms.
  • Studies have shown that hyperthyroidism can affect the metabolism and efficacy of various medications, including warfarin 4.
  • Additionally, the treatment of Graves' disease often involves the use of thionamides, such as methimazole, which can have varying effects on thyroid function and symptom management 2, 3, 5, 6.
  • The lack of direct evidence on Qsymia and Graves' disease interaction suggests that further research is needed to fully understand the contraindication.
  • It is possible that the contraindication is based on the potential for Qsymia to worsen hyperthyroidism symptoms or interact with medications used to treat Graves' disease, but this is speculative and not supported by the provided studies 2, 3, 4, 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

An update on the medical treatment of Graves' hyperthyroidism.

Journal of endocrinological investigation, 2014

Research

Non-thionamide antithyroid drug options in Graves' hyperthyroidism.

Expert review of endocrinology & metabolism, 2023

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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