Drug interactions between Questran and Synthroid
Interactions between your drugs
cholestyramine ↔ levothyroxine
Applies to:Questran (cholestyramine) and Synthroid (levothyroxine)
Taking the levothyroxine and cholestyramine doses too close together may interfere with the absorption of levothyroxine and reduce its effectiveness. To prevent or minimize the interaction, levothyroxine and cholestyramine should be taken at least four hours apart. Contact your doctor if you experience signs and symptoms of reduced thyroid function such as fatigue; sluggishness; constipation; depression; hoarseness; unexplained weight gain; sensitivity to cold; pale, dry skin; muscle aches, weakness, or tenderness; joint pain, stiffness, or swelling; heavier than normal menstruation periods; or brittle fingernails and hair. 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.
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.