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Drug Interaction Report

5 potential interactions and/or warnings found for the following 3 drugs:

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Interactions between your drugs

Moderate

carBAMazepine levothyroxine

Applies to: Tegretol XR (carbamazepine), Levothyrox (levothyroxine), Synthroid (levothyroxine)

Using carBAMazepine together with levothyroxine can decrease the effects of levothyroxine. This can cause fatigue, weight gain, constipation, and low blood pressure. Talk with your doctor before using carBAMazepine while you are using levothyroxine. You may need a dose adjustment and may need to check your thyroid levels more often. 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.

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No other interactions were found between your selected drugs. However, this does not necessarily mean no other interactions exist. Always consult your healthcare provider.

Drug and food interactions

Moderate

carBAMazepine food

Applies to: Tegretol XR (carbamazepine)

You should preferably avoid the regular consumption of grapefruits and grapefruit juice while taking carBAMazepine. This can cause carBAMazepine levels to increase. You should report signs of carBAMazepine side effects such as nausea, visual disturbances, dizziness, or muscle weakness to your doctor. You should avoid or limit the use of alcohol while being treated with carBAMazepine. Alcohol can increase the nervous system side effects of carBAMazepine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. Talk to your doctor or pharmacist if you have any questions or concerns.

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Moderate

levothyroxine food

Applies to: Levothyrox (levothyroxine), Synthroid (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 and 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.

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Moderate

levothyroxine food

Applies to: Levothyrox (levothyroxine), Synthroid (levothyroxine)

Using multivitamin with minerals together with levothyroxine may decrease the effects of levothyroxine. You should separate the administration of levothyroxine and multivitamin 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.

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Therapeutic duplication warnings

Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.

Duplication

Thyroid hormones

Therapeutic duplication

The recommended maximum number of medicines in the 'thyroid hormones' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'thyroid hormones' category:

  • Levothyrox (levothyroxine)
  • Synthroid (levothyroxine)

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.


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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.

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Further information

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