Drug Interactions between levothyroxine and Marinol

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.

Do not use alcohol while you are receiving treatment with droNABinol. This may increase nervous system side effects such as somnolence, dizziness, confusion, difficulty concentrating, and impairment in thinking and judgment. You should also avoid consuming grapefruit and grapefruit juice, as this may increase the blood levels and effects of droNABinol. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. Take droNABinol exactly as your doctor tells you to. Do not exceed the dose of droNABinol prescribed for you or use the medication more frequently or for a longer duration than prescribed by your doctor. Also, 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.

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.