Thyroid Disorders Community
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Does Benicar (Olmesartan) reduces hypothyroidism or worsens hyperthyroidism?

I was just diagnosed with T3 hyperthyroidism.

Benicar almost gave me a heart attack on the first dose, only 20 mg.
Does it worsen hyperthyroidism or cause heat intolerance?

A guy uses Benicar off-label for chronic fatigue or something in the so called Marshall Protocol. While its effectiveness remains dubious.
He claims Benicar reduces the need for exogenous thyroid hormones in hypothyroid patients even getting to the point of hyperthyroidism.

"Patients who are taking thyroid supplements should be aware that their need for those supplements may change within a day or two of starting olmesartan (Benicar)."
"Patients have also noticed that their need for thyroid medication drops as they progress along on the Marshall Protocol. For this reason, physicians may need to monitor their patients' thyroid function more closely than they otherwise would. Any of the following signs of hyperthyroidism may imply the need to wean thyroid medication:.."

Maybe there is some truth in his observations on Benicar and thyroid?
Has anyone felt hyperthyroid symptoms on Benicar?
1 Responses
1756321 tn?1547098925
Sounds more like a serious side effect of Benicar than worsening hyperthyroid symptoms. There is a listed interaction for thyroid function tests but states "without associated thyroid disturbance."

Excerpts from the Drug website...

"Benicar HCT (hydrochlorothiazide / olmesartan) Disease Interactions...

"Thiazides (Includes Benicar HCT) ↔ Thyroid Function Tests
Moderate Potential Hazard, Moderate plausibility

Applies to: Thyroid Disease

Thiazide diuretics may decrease serum PBI (protein-bound iodine) levels without associated thyroid disturbance. Clinicians should be cognizant of this effect when prescribing or administering thiazide therapy to patients with thyroid disorders."


Benicar side effects

"Get emergency medical help if you have any of these signs of an allergic reaction to Benicar: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

a light-headed feeling, like you might pass out;
little or no urinating;
severe or ongoing diarrhea with weight loss;
chest pain, fast heart rate; or
swelling in your hands or feet.

Common Benicar side effects may include:


This is not a complete list of side effects and others may occur."
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649848 tn?1534637300
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1756321 tn?1547098925
Queensland, Australia
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