bronkk asked
Can I eat grapefruit while taking Flomax (Tamsulosin)?
Answer
Tamsulosin (brand name Flomax) is metabolized in the body mainly by an enzyme known as CYP 3A4. Grapefruit juice is well known to be an inhibitor of this enzyme. This inhibition can lead to tamsulosin not being metabolized/broken down as extensively as normal. Therefore, the levels of tamsulosin can be much higher than normal and therefore the possibility of side effects is greater. It should be noted that I am not aware of any actual studies with grapefruit juice and tamsulosin and after a quick search of drug studies, there doesn't appear to be any completed for this drug interaction. Therefore this interaction is more based on theory than actual real life experience. Possible side effects of a higher dose of tamsulosin include the following:
- Excess dizziness & drowsiness
- Lack of energy
- Nausea/GI problems
- Runny nose/Cold like symptoms
The current recommendation is to try and avoid taking grapefruit juice and tamsulosin together as it could lead to those possible increase in side effects. If you already consume grapefruit juice fairly consistently, you would probably be okay to continue doing so as you have likely adjusted to taking the tamsulosin and grapefruit juice together. In fact, the interaction is listed by multiple drug references as "moderate" so you may be okay taking both together and just monitoring for side effects.
Certain drugs have a far more significant interaction with grapefruit juice such as Lipitor as that interaction can cause severe muscle problems. It is always a good idea to check with a health care professional regarding grapefruit juice and other possible food interactions with your medication. There is a good list of grapefruit juice drug interactions over at WebMD. The list isn't comprehensive, but it gives you a good idea of just how many possible interactions there are! If you ever want to know about a specific medication with grapefruit juice, let us know and we would be more than happy to answer!
