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Drug interactions between levothyroxine and Tri-Sprintec

Results for the following 2 drugs:
levothyroxine
Tri-Sprintec (ethinyl estradiol/norgestimate)

Interactions between your drugs

Moderate

ethinyl estradiol levothyroxine

Applies to: Tri-Sprintec (ethinyl estradiol / norgestimate) and levothyroxine

Before taking ethinyl estradiol, tell your doctor if you also use levothyroxine. You may need dose adjustments or special tests in order to safely take both medications together. If you are already taking ethinyl estradiol and levothyroxine, your thyroid levels may need to be measured if your dose of ethinyl estradiol is changed or stopped. You should notify your doctor if you have symptoms of low thyroid such as tiredness, feeling cold, constipation, unexplained weight gain, depression, joint or muscle pain, thinning hair or hair loss, dry skin, hoarseness, and abnormal menstrual periods. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using your medications without first talking to your doctor first.

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Drug and food interactions

Moderate

levothyroxine food

Applies to: levothyroxine

The timing of meals relative to your levothyroxine dose can affect 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 by foods such as soybean flour, cotton seed meal, walnuts, dietary fiber, calcium, and calcium fortified juices. 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.

When levothyroxine is given during continuous enteral nutrition (tube feedings) for more than 7 days, the tube feeding should be interrupted for at least one hour before and one hour after the dose of levothyroxine. You may need more frequent blood tests to monitor levothyroxine levels.

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Moderate

norgestimate food

Applies to: Tri-Sprintec (ethinyl estradiol / norgestimate)

Consumer information for this interaction is not currently available.

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of drugs that undergo significant presystemic metabolism by CYP450 3A4. Grapefruit and grapefruit juice should be avoided if an interaction is suspected. Orange juice is not expected to interact with these drugs.

Minor

ethinyl estradiol food

Applies to: Tri-Sprintec (ethinyl estradiol / norgestimate)

Consumer information for this minor interaction is not currently available. Some minor drug interactions may not be clinically relevant in all patients. Minor drug interactions do not usually cause harm or require a change in therapy. However, your healthcare provider can determine if adjustments to your medications are needed.

For clinical details see professional interaction data.

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
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 information available.

Do not stop taking any medications without consulting your healthcare provider.

Further information

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

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