Drug interactions between Qsymia and Synthroid
Interactions between your drugs
levothyroxine ↔ phentermine
Applies to:Synthroid (levothyroxine) and Qsymia (phentermine/topiramate)
Talk to your doctor before using levothyroxine together with phentermine. Combining these medications may increase the risk of cardiovascular side effects such as high blood pressure, palpitation, chest pain, and irregular heart beat. If you have preexisting heart disease, your condition may worsen. You may need a dose 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.
Drug and food interactions
Applies to: Synthroid (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.
Applies to: Qsymia (phentermine / topiramate)
Using phentermine with alcohol can increase the risk of cardiovascular side effects such as increased heart rate, chest pain, or blood pressure changes. In addition, you may also be more likely to experience nervous system side effects such as dizziness, drowsiness, depression, and difficulty concentrating. You should avoid or limit the use of alcohol while being treated with phentermine. Do not use more than the recommended dose of phentermine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medication without first talking to your doctor.
Therapeutic duplication warnings
No therapeutic duplications were found for your selected drugs.
Drug Interaction Classification
|No information available.|
Do not stop taking any medications without consulting your healthcare provider.