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Drug Interaction Report

Drug interactions for the following 11 drug(s):

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Tamoxen (tamoxifen)
sodium phenylbutyrate
Euthyrox (levothyroxine)
temozolomide
metformin
omeprazole
Dexasone (dexamethasone)
Doxy 100 (doxycycline)
ribociclib
simvastatin
canagliflozin

Interactions between your drugs

Major

tamoxifen ribociclib

Applies to: Tamoxen (tamoxifen), ribociclib

Using ribociclib together with tamoxifen can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). In addition, ribociclib may increase the blood levels of tamoxifen. This can increase the risk of an irregular heart rhythm as well as other serious side effects. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Talk to your doctor if you have any questions or concerns. You should seek immediate medical attention if you develop sudden or excessive drowsiness, dizziness, lightheadedness, fainting, confusion, shortness of breath, or heart palpitations during treatment with these medications, whether together or alone. 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

simvastatin ribociclib

Applies to: simvastatin, ribociclib

Ribociclib may increase the blood levels of simvastatin. This can increase the risk of side effects such as liver damage and a rare but serious condition called rhabdomyolysis that involves the breakdown of skeletal muscle tissue. In some cases, rhabdomyolysis can cause kidney damage and even death. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Let your doctor know immediately if you have unexplained muscle pain, tenderness, or weakness while taking these medications, especially if these symptoms are accompanied by fever or dark colored urine. You should also seek immediate medical attention if you develop fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. 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

metFORMIN ribociclib

Applies to: metformin, ribociclib

Ribociclib may increase the blood levels and effects of metFORMIN. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. 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

dexamethasone ribociclib

Applies to: Dexasone (dexamethasone), ribociclib

Dexamethasone may reduce the blood levels of ribociclib. In some cases, this may make the medication less effective in treating your cancer. Talk to your doctor if you have any questions or concerns. 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 canagliflozin

Applies to: Euthyrox (levothyroxine), canagliflozin

Levothyroxine may interfere with blood glucose control and reduce the effectiveness of canagliflozin and other diabetic medications. Monitor your blood sugar levels closely. You may need a dose adjustment of your diabetic medications during and after treatment with levothyroxine. 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

dexamethasone canagliflozin

Applies to: Dexasone (dexamethasone), canagliflozin

Dexamethasone may interfere with blood glucose control and reduce the effectiveness of canagliflozin and other diabetic medications. Monitor your blood sugar levels closely. You may need a dose adjustment of your diabetic medications during and after treatment with dexamethasone. 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

dexamethasone sodium phenylbutyrate

Applies to: Dexasone (dexamethasone), sodium phenylbutyrate

Talk to your doctor before using dexamethasone together with sodium phenylbutyrate. Dexamethasone may increase ammonia levels in the blood and reduce the effectiveness of sodium phenylbutyrate in the treatment of urea cycle disorders. You may need a dosage adjustment or more frequent monitoring by your doctor 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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Moderate

dexamethasone metFORMIN

Applies to: Dexasone (dexamethasone), metformin

Dexamethasone may interfere with blood glucose control and reduce the effectiveness of metFORMIN and other diabetic medications. Monitor your blood sugar levels closely. You may need a dose adjustment of your diabetic medications during and after treatment with dexamethasone. 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 metFORMIN

Applies to: Euthyrox (levothyroxine), metformin

Levothyroxine may interfere with blood glucose control and reduce the effectiveness of metFORMIN and other diabetic medications. Monitor your blood sugar levels closely. You may need a dose adjustment of your diabetic medications during and after treatment with levothyroxine. 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

omeprazole simvastatin

Applies to: omeprazole, simvastatin

Talk to your doctor before using simvastatin together with omeprazole. Combining these medications may increase the blood levels and effects of simvastatin. This can increase the risk of side effects such as liver damage and a rare but serious condition called rhabdomyolysis that involves the breakdown of skeletal muscle tissue. In some cases, rhabdomyolysis can cause kidney damage and even death. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications, or your doctor may prescribe alternative medications that do not interact. Let your doctor know immediately if you have unexplained muscle pain, tenderness, or weakness during treatment with simvastatin or similar medications, especially if these symptoms are accompanied by fever or dark colored urine. You should also seek immediate medical attention if you develop fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. 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

dexamethasone tamoxifen

Applies to: Dexasone (dexamethasone), Tamoxen (tamoxifen)

Dexamethasone may reduce the blood levels and effects of tamoxifen. Contact your doctor if your symptoms worsen or your condition changes during treatment with these medications. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring 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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Minor

levothyroxine simvastatin

Applies to: Euthyrox (levothyroxine), simvastatin

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.

No other interactions were found between your selected drugs.
Note: this does not necessarily mean no interactions exist. Always consult with your doctor or pharmacist.

Other drug and disease interactions

Drug and food interactions

Major

simvastatin food

Applies to: simvastatin

Grapefruit juice can significantly increase the blood levels of simvastatin. This can increase the risk of side effects such as liver damage and a rare but serious condition called rhabdomyolysis that involves the breakdown of skeletal muscle tissue. In some cases, rhabdomyolysis can cause kidney damage and even death. You should avoid the consumption of grapefruit or grapefruit juice during treatment with simvastatin. Let your doctor know immediately if you have unexplained muscle pain, tenderness, or weakness during treatment, especially if these symptoms are accompanied by fever or dark colored urine. You should also seek immediate medical attention if you develop fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. 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

ribociclib food

Applies to: ribociclib

Patients should not consume pomegranates, pomegranate juice, grapefruit, or grapefruit juice during treatment with ribociclib unless directed otherwise by your doctor. Pomegranate juice or grapefruit juice can increase the blood levels of ribociclib. You may be more likely to experience side effects such as nausea; vomiting; diarrhea; loss of appetite; abdominal pain; mouth sores; hair loss; weakness; and impaired bone marrow function resulting in low numbers of different types of blood cells, which can increase the risk of anemia, bleeding problems, and infections. 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

tamoxifen food

Applies to: Tamoxen (tamoxifen)

Talk to your doctor before using tamoxifen with soy products. There is some evidence that substances present in soy may stimulate breast tumor growth and interfere with the action of tamoxifen, although this has not been proven. Whether soy products are effective for hot flashes is also uncertain. 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: Euthyrox (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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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

Cell cycle non-phase specific antineoplastics

Therapeutic duplication

The recommended maximum number of medicines in the 'cell cycle non-phase specific antineoplastics' category to be taken concurrently is usually two. Your list includes three medicines belonging to the 'cell cycle non-phase specific antineoplastics' category:

  • Tamoxen (tamoxifen)
  • temozolomide
  • ribociclib

Note: The benefits of taking this combination of medicines may outweigh any risks associated with therapeutic duplication. This information does not take the place of talking to your doctor. Always check with your healthcare provider to determine if any adjustments to your medications are needed.

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.

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