A little grapefruit juice to wash down that medicine? You might want to think twice.

I love eating grapefruit and drinking grapefruit juice. That's why it's so annoying when I'm taking a new medication and I find out that grapefruit is temporarily off the menu. That's because grapefruit doesn't always "play well" with some medicines. Of course, doctors and pharmacists don't always remember to tell you about grapefruit/drug interactions in advance... and who actually reads ALL of the small type on the drug inserts or handouts anyway?

So what can happen if you mix grapefruit juice or slices with some medications? Well, that depends on the drug. In some cases, it can make your doses stronger than they should be; in other cases, it could make your medicine worthless by canceling out the drug's action in your body.

That's why I was thrilled to find an online resource that lists grapefruit-drug interactions. Your best option, of course, is always to ask your doctor or pharmacist if grapefruit interacts with your medicine. Find out if you'll need to avoid grapefruit juice and slices within a certain time frame of taking your medicine, or if you'll have to stay away from them altogether. If you forget to ask your doctor or pharmacist, though, another good option is to keep this list handy.

The following information is posted with the permission of Dr. Dean Elbe of Food-Medication Interactions. This information is from 2007; an updated listing will be available soon.

Key:
1 - Manufacturer recommends avoidance.
2 - Use with grapefruit/related citrus only on advice of a physician.
3 - Serum/Plasma level monitoring required/recommended.
4 - Minor interaction, not clinically significant.
5 - Interaction suspected, but no formal studies.
6 - No formal studies, but lacks a cardiotoxic metabolite.
7 - Not metabolized by 3A4, no interaction suspected.
8 - No interaction when drug administered parenterally [by injection, IV, or means other than eating/ingesting]
9 - Withdrawn from market.
10 - Blood levels/bioavailability decreased.
11 – Risk higher in CYP 2D6 poor metabolizers.

Medications that should be avoided with grapefruit:
amiodarone (Cordarone) 8
astemizole (Hismanal) 5, 9
atorvastatin (Lipitor)
budesonide (Entocort) 8
buspirone (BuSpar)
cerivastatin (Baycol) 5, 9
cilostazol (Pletal) 5
cisapride (Propulsid, Prepulsid) 9
colchicine 5
eletriptan (Relpax) 5
etoposide (Vepesid) 8, 10
halofantrine (Halfan)
lovastatin (Mevacor)
mifepristone (Mifeprex) 5
pimozide (Orap) 5
quinidine (Quinaglute, Quinidex) 8, 10
sildenafil (Viagra)
simvastatin (Zocor) 8
sirolimus (Rapamune) 1, 5
terfenadine (Seldane) 9
ziprasidone (Geodon) 5

Use with grapefruit with caution:
albendazole (Albenza)
alfentanil (Alfenta) 8
alfuzosin (Uroxatral) 5
almotriptan (Axert) 5
aprepitant (Emend) 5
aripiprazole (Abilify) 5
bupropion (Wellbutrin, Zyban) 5
carbamazepine (Tegretol) 3
cinacalcet (Sensipar) 5
clomipramine (Anafranil)
cyclosporine (Neoral) 2, 3, 8
darifenacin (Enablex) 5
delavirdine (Rescriptor) 5
dextromethorphan
diazepam (Valium) 8
dofetilide (Tikosyn) 5
efavirenz (Sustiva) 5
erlotinib (Tarceva) 5
erythromycin (Eryc, E-mycin, Erythromid, Erybid) 8
eszopiclone (Lunesta) 5
felodipine (Renedil, Plendil)
fexofenadine (Allegra) 10
fluvoxamine (Luvox)
gefitinib (Iressa) 5
imatinib mesylate (Gleevec/Glivec) 5
indinavir (Crixivan) 10
itraconazole (Sporanox) 10
losartan (Cozaar)
methadone (Dolophine) 5
methylprednisolone (Medrol) 8
midazolam (Versed) 8
montelukast (Singulair) 5
nicardipine (Cardene) 8
nifedipine (Procardia)
nimodipine (Nimotop)
nisoldipine (Sular)
oxybutynin (Ditropan) 5
propafenone (Rythmol) 5, 11
quetiapine fumarate (Seroquel) 5
quinine
ramelteon (Rozerem) 5
saquinavir (Invirase) 2
sertraline (Zoloft)
solifenacin (Vesicare) 5
tacrolimus (Prograf) 2, 3, 8
tamoxifen (Nolvadex) 5
tamsulosin (Flomax) 5
tolterodine (Detrol) 5
triazolam (Halcion)
trazodone (Desyrel) 5

Medications with no significant interaction with grapefruit
Drugs in this section have all been studied with grapefruit,
and found to have either a minimal/negligible interaction:

acebutolol (Monitan, Sectral) 4
alprazolam (Xanax) 4
amlodipine (Norvasc) 4
amprenavir (Agenerase) 4, 10
caffeine 4, 8
carvedilol (Coreg) 4
clarithromycin (Biaxin)
clozapine (Clozaril) 4
digoxin (Lanoxin) 8
diltiazem (Cardizem) 4, 8
eplerenone (Inspra) 4
ethinyl estradiol 4, 8
fentanyl (Actiq) 4, 8
haloperidol (Haldol) 8
lansoprazole (Prevacid) 4, 8
levothyroxine (Eltroxin, Synthroid) 4, 8
omeprazole (Losec, Prilosec) 4
phenytoin (Dilantin) 8
pravastatin (Pravachol)
prednisone (Deltasone)
scopolamine (Hyoscine) 4, 8
17-β estradiol 4, 8
telithromycin (Ketek) 4
theophylline (Theo-Dur, Uniphyl)
verapamil (Calan, Isoptin, Verelan) 8
warfarin (Coumadin) 8

Medications considered safe for use with grapefruit:
cetirizine (Zyrtec, Reactine) 6
desloratadine (Aerius, Clarinex) 7
fluvastatin (Lescol) 7
loratadine (Claritin) 6
praziquantel (Biltricide)
rosuvastatin (Crestor) 7