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Can you take Levothyroxine with Losartan?

No drug interactions found, but 21 warnings to review for the following 2 drugs:

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Drug interactions

There were no interactions found between levothyroxine and losartan. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.

Food/lifestyle interactions

Moderate food/lifestyle interactions

Moderate:

levothyroxine Food/Lifestyle

Applies to: levothyroxine

The timing of meals relative to your oral levothyroxine dose can affect the absorption of the medication.

Therefore, levothyroxine should be taken on a consistent schedule with regard to time of day and relation to meals to avoid large fluctuations in blood levels, which may alter its effects.

In addition, absorption of levothyroxine may be decreased and/or delayed by foods such as:

  • soybean flour
  • cotton seed meal
  • walnuts
  • dietary fiber
  • calcium
  • calcium fortified juices
  • grapefruit or grapefruit juice

These foods should be avoided within several hours of dosing if possible.

It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Moderate:

losartan Food/Lifestyle

Applies to: losartan

If you are taking losartan you should avoid potassium-containing salt substitutes or over-the-counter potassium supplements without first talking to your doctor. This can cause high levels of potassium in your blood.

High levels of potassium can cause:

  • weakness
  • irregular heartbeat
  • confusion
  • tingling of the extremities
  • feelings of heaviness in the legs

Call your doctor at once if you have any of these symptoms.

In some patients grapefruits and grapefruit juice may decrease the efficacy of losartan. Grapefruits and grapefruit juice should be avoided if an interaction is suspected. Orange juice is not expected to interact.

Moderate:

levothyroxine multivitamins with minerals

Applies to: levothyroxine

Using multivitamins with minerals together with levothyroxine may decrease the effects of levothyroxine.

You should separate the administration of levothyroxine and multivitamins with minerals by at least 4 hours.

If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications.

It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Disease interactions

18 potential interactions Applies to: 16 conditions, including High Blood Pressure, Heart Failure, Seizures, Hyperthyroidism, and Heart Disease.

Adrenal Insufficiency

Major:

levothyroxine

Levothyroxine has a major potential interaction with Adrenal Insufficiency.

The use of thyroid hormones is contraindicated in patients with uncorrected adrenal insufficiency. Thyroid hormones increase tissue demand for adrenocortical hormones and may precipitate acute adrenal crisis. In patients with controlled adrenal insufficiency or other endocrine disorders, therapy for these concomitant disorders may need to be adjusted following thyroid replacement, since hypothyroidism often obscure or diminish the signs and symptoms of these conditions. Clinical monitoring of thyroid and adrenal function as well as any other appropriate endocrine function is recommended during thyroid hormone therapy.

Angioedema

Major:

losartan

Losartan has a major potential interaction with Angioedema.

The use of these agents is contraindicated in patients with a history of angioedema related to previous angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB) therapy or in patients with hereditary angioedema. Patients with a history of angioedema unrelated to these agents may be at increased risk of angioedema while receiving angiotensin II receptor (AR) antagonists. Patients should be advised to immediately report any signs or symptoms suggestive of angioedema (swelling of face, extremities, eyes, lips, or tongue, or difficulty swallowing or breathing) and to stop taking the medication until otherwise directed by their physician. Emergency therapy and/or measures to prevent airway obstruction are required for angioedema involving the tongue, glottis, or larynx. Treatment with angiotensin II receptor (AR) antagonists should be discontinued permanently if angioedema develops in association with therapy.

Biliary Obstruction

Moderate:

losartan

Losartan has a moderate potential interaction with Biliary Obstruction.

Losartan is converted in the liver to an active carboxylic acid metabolite and several inactive metabolites, and both parent drug and metabolites are eliminated by the kidney (35%) as well as by biliary excretion (60%). Dosage adjustments are not necessary in patients with renal impairment unless they are also volume-depleted, in which case therapy should be initiated under medical supervision. In patients with cirrhosis, however, significantly increased plasma concentrations of parent drug and active metabolite have been reported. Therapy with losartan should be initiated cautiously at a reduced dosage (50%) in patients with impaired liver function.

Dehydration

Major:

losartan

Losartan has a major potential interaction with Dehydration.

Angiotensin II receptor (AR) antagonists can cause symptomatic hypotension in patients with an activated renin-angiotensin system, such as volume- and/or sodium-depleted patients. Therapy with AR antagonists should be administered cautiously in such patients and in those predisposed to hypovolemic or hyponatremic states (e.g., patients on diuretic therapy, especially if high doses were used or if recently instituted; those on dietary salt restriction; renal dialysis patients). Volume and/or sodium depletion should be corrected prior to initiating therapy with AR antagonists, and the patient should be hemodynamically stable. Ideally, patients at risk for excessive hypotension should initiate AR antagonist therapy under close medical supervision, preferably with a lower dose, and followed closely for the first 2 weeks of treatment and whenever the dosage of AR antagonist or diuretic is increased.

Diabetes Insipidus

Moderate:

levothyroxine

Levothyroxine has a moderate potential interaction with Diabetes Insipidus.

Since hypothyroidism often obscure or diminish the signs and symptoms of endocrine disorders such as diabetes mellitus or diabetes insipidus, thyroid replacement therapy may aggravate the intensity of symptoms associated with these conditions. Patients with endocrine disorders should be monitored more closely during thyroid hormone therapy, and their medication regimen adjusted accordingly. If thyroid medication is later discontinued, a downward readjustment of insulin or oral hypoglycemic agent may be necessary in patients with diabetes mellitus to avoid hypoglycemia.

Diabetes Mellitus

Major:

losartan

Losartan has a major potential interaction with Diabetes Mellitus.

The coadministration of some angiotensin II receptor blocker agents with aliskiren is contraindicated in patients with diabetes.

Moderate:

levothyroxine

Levothyroxine has a moderate potential interaction with Diabetes Mellitus.

Since hypothyroidism often obscure or diminish the signs and symptoms of endocrine disorders such as diabetes mellitus or diabetes insipidus, thyroid replacement therapy may aggravate the intensity of symptoms associated with these conditions. Patients with endocrine disorders should be monitored more closely during thyroid hormone therapy, and their medication regimen adjusted accordingly. If thyroid medication is later discontinued, a downward readjustment of insulin or oral hypoglycemic agent may be necessary in patients with diabetes mellitus to avoid hypoglycemia.

Heart Disease

Major:

levothyroxine

Levothyroxine has a major potential interaction with Heart Disease.

Thyroid hormones cause increases in myocardial contractility and heart rate as a result of increased metabolic demands and oxygen consumption. Therapy with thyroid hormones should be administered cautiously and initiated at reduced dosages in patients with cardiovascular disorders such as angina, coronary artery disease, and hypertension. Clinical monitoring of cardiovascular function is recommended. If chest pain or exacerbation of cardiovascular disease occurs, the dosage of thyroid hormone should be reduced, even at the expense of achieving euthyroid state. Thyroid hormones should not be administered to patients with an acute myocardial infarction that is not complicated by hypothyroidism.

Heart Failure

Moderate:

losartan

Losartan has a moderate potential interaction with Heart Failure.

Angiotensin II receptor (AR) antagonists can cause renal impairment in patients whose renal function depends on the activity of the renin-angiotensin-aldosterone system. In addition, symptomatic hypotension can occur in susceptible individuals, which may compromise renal and myocardial perfusion. In patients with severe congestive heart failure (CHF), treatment with AR antagonists has been associated with oliguria and/or progressive azotemia and, rarely, renal failure, myocardial ischemia, and death. Therapy with AR antagonists should be initiated cautiously in patients with severe CHF, especially when accompanied by volume and/or sodium depletion. In patients who experience a decline in renal function, discontinuation of AR antagonist therapy is usually not required provided there is symptomatic improvement of the heart failure and renal deterioration is well-tolerated. Transient hypotension is also not a contraindication to further treatment with AR antagonists, since therapy can usually be reinstated without difficulty after blood pressure stabilizes.

Hemodialysis

Major:

losartan

Losartan has a major potential interaction with Hemodialysis.

Angiotensin II receptor (AR) antagonists can cause symptomatic hypotension in patients with an activated renin-angiotensin system, such as volume- and/or sodium-depleted patients. Therapy with AR antagonists should be administered cautiously in such patients and in those predisposed to hypovolemic or hyponatremic states (e.g., patients on diuretic therapy, especially if high doses were used or if recently instituted; those on dietary salt restriction; renal dialysis patients). Volume and/or sodium depletion should be corrected prior to initiating therapy with AR antagonists, and the patient should be hemodynamically stable. Ideally, patients at risk for excessive hypotension should initiate AR antagonist therapy under close medical supervision, preferably with a lower dose, and followed closely for the first 2 weeks of treatment and whenever the dosage of AR antagonist or diuretic is increased.

High Blood Pressure

Major:

levothyroxine

Levothyroxine has a major potential interaction with High Blood Pressure.

Thyroid hormones cause increases in myocardial contractility and heart rate as a result of increased metabolic demands and oxygen consumption. Therapy with thyroid hormones should be administered cautiously and initiated at reduced dosages in patients with cardiovascular disorders such as angina, coronary artery disease, and hypertension. Clinical monitoring of cardiovascular function is recommended. If chest pain or exacerbation of cardiovascular disease occurs, the dosage of thyroid hormone should be reduced, even at the expense of achieving euthyroid state. Thyroid hormones should not be administered to patients with an acute myocardial infarction that is not complicated by hypothyroidism.

Hyperkalemia

Moderate:

losartan

Losartan has a moderate potential interaction with Hyperkalemia.

Drugs that inhibit the renin-angiotensin, such as angiotensin II receptor antagonist system can cause hyperkalemia. Concomitant use of these agents with drugs that increase potassium levels may increase the risk of hyperkalemia. Use caution when using these agents together and monitor serum potassium periodically.

Hyperthyroidism

Major:

levothyroxine

Levothyroxine has a major potential interaction with Hyperthyroidism.

The use of thyroid hormones is contraindicated in patients with untreated thyrotoxicosis of any etiology, since thyroid hormones may exacerbate the condition.

Hyponatremia

Major:

losartan

Losartan has a major potential interaction with Hyponatremia.

Angiotensin II receptor (AR) antagonists can cause symptomatic hypotension in patients with an activated renin-angiotensin system, such as volume- and/or sodium-depleted patients. Therapy with AR antagonists should be administered cautiously in such patients and in those predisposed to hypovolemic or hyponatremic states (e.g., patients on diuretic therapy, especially if high doses were used or if recently instituted; those on dietary salt restriction; renal dialysis patients). Volume and/or sodium depletion should be corrected prior to initiating therapy with AR antagonists, and the patient should be hemodynamically stable. Ideally, patients at risk for excessive hypotension should initiate AR antagonist therapy under close medical supervision, preferably with a lower dose, and followed closely for the first 2 weeks of treatment and whenever the dosage of AR antagonist or diuretic is increased.

Liver Disease

Moderate:

losartan

Losartan has a moderate potential interaction with Liver Disease.

Losartan is converted in the liver to an active carboxylic acid metabolite and several inactive metabolites, and both parent drug and metabolites are eliminated by the kidney (35%) as well as by biliary excretion (60%). Dosage adjustments are not necessary in patients with renal impairment unless they are also volume-depleted, in which case therapy should be initiated under medical supervision. In patients with cirrhosis, however, significantly increased plasma concentrations of parent drug and active metabolite have been reported. Therapy with losartan should be initiated cautiously at a reduced dosage (50%) in patients with impaired liver function.

Renal Dysfunction

Moderate:

losartan

Losartan has a moderate potential interaction with Renal Dysfunction.

Losartan is converted in the liver to an active carboxylic acid metabolite and several inactive metabolites, and both parent drug and metabolites are eliminated by the kidney (35%) as well as by biliary excretion (60%). Dosage adjustments are not necessary in patients with renal impairment unless they are also volume-depleted, in which case therapy should be initiated under medical supervision. In patients with cirrhosis, however, significantly increased plasma concentrations of parent drug and active metabolite have been reported. Therapy with losartan should be initiated cautiously at a reduced dosage (50%) in patients with impaired liver function.

Moderate:

losartan

Losartan has a moderate potential interaction with Renal Dysfunction.

Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system and by diuretics. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe congestive heart failure, or volume depletion) may be at particular risk of developing acute renal failure with these agents. Monitor renal function periodically in these patients. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function with these agents.

Seizures

Moderate:

levothyroxine

Levothyroxine has a moderate potential interaction with Seizures.

Thyroid hormones may alter the seizure threshold. Seizures have been reported rarely following the initiation of levothyroxine therapy. Therapy with thyroid hormones should be administered cautiously in patients predisposed to seizures.

More resources

levothyroxine

A total of 254 drugs are known to interact with levothyroxine.

losartan

A total of 369 drugs are known to interact with losartan.

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.