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Are there any interactions with medications?



Isoniazid (INH, Nydrazid)
Interaction Rating: Major Do not take this combination.

Garlic might reduce how much isoniazid (INH, Nydrazid) the body absorbs. This might decrease how well isoniazid (INH, Nydrazid) works. Don't take garlic if you take isoniazid (INH, Nydrazid).



Atazanavir (Reyataz)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Garlic might reduce how much atazanavir (Reyataz) the body absorbs. This might decrease how well atazanavir (Reyataz) works. Talk to your doctor before taking garlic if you are taking atazanavir (Reyataz).



Medications changed by the liver (Cytochrome P450 2E1 (CYP2E1) substrates)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Some medications are changed and broken down by the liver. Garlic oil might decrease how quickly the liver breaks down some medications. Taking garlic oil along with some medications that are changed by the liver can increase the effects and side effects of your medication. Before taking garlic oil, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include acetaminophen, chlorzoxazone (Parafon Forte), ethanol, theophylline, and drugs used for anesthesia during surgery such as enflurane (Ethrane), halothane (Fluothane), isoflurane (Forane), and methoxyflurane (Penthrane).



Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Some medications are changed and broken down by the liver. Garlic might increase how quickly the liver breaks down some medications. Taking garlic along with some medications that are broken down by the liver can decrease the effectiveness of some medications. Before taking garlic, talk to your healthcare provider if you are taking any medications that are changed by the liver.

Medications that might be affected include certain heart medications called calcium channel blockers (diltiazem, nicardipine, verapamil), cancer drugs (etoposide, paclitaxel, vinblastine, vincristine, vindesine), fungus-fighting drugs (ketoconazole, itraconazole), glucocorticoids, alfentanil (Alfenta), cisapride (Propulsid), fentanyl (Sublimaze), lidocaine (Xylocaine), losartan (Cozaar), midazolam (Versed), and others.



Medications for high blood pressure (Antihypertensive drugs)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Garlic might lower blood pressure in some people. Taking garlic along with medications used for lowering high blood pressure might cause your blood pressure to go too low. Do not take too much garlic if you are taking medications for high blood pressure.

Some medications for high blood pressure include nifedipine (Adalat, Procardia), verapamil (Calan, Isoptin, Verelan), diltiazem (Cardizem), isradipine (DynaCirc), felodipine (Plendil), amlodipine (Norvasc), and others.



Medications for HIV/AIDS (Protease Inhibitors)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Taking garlic might decrease the amount of HIV/AIDS medication that can enter into the bloodstream. This could decrease the effectiveness of some medications used for HIV/AIDS.

Some of these medications used for HIV/AIDS include amprenavir (Agenerase), nelfinavir (Viracept), ritonavir (Norvir), and saquinavir (Fortovase, Invirase).



Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Garlic might slow blood clotting. Taking garlic along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.



Saquinavir (Fortovase, Invirase)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Saquinavir (Fortovase, Invirase) is a medication taken for HIV. Garlic might decrease how much saquinavir goes into the blood. This might decrease the effectiveness of saquinavir (Fortovase, Invirase).



Warfarin (Coumadin)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Warfarin (Coumadin) is used to slow blood clotting. Garlic might increase the effectiveness of warfarin (Coumadin). Taking garlic along with warfarin (Coumadin) might increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Dosing considerations for Garlic.

The following doses have been studied in scientific research:

BY MOUTH:
  • For hardening of the arteries: A 300 mg garlic powder tablet (Kwai, Lichtwer Pharma), taken as a single dose or three times daily for up to 4 years, has been used. Also, 150 mg of a specific garlic supplement (Allicor, INAT-Farma, Moscow, Russia) twice daily for 24 months has been used. Combination products containing garlic have also been used. A specific aged garlic extract supplement (Kyolic, Total Heart Health, Formula 108, Wakunga) containing 250 mg of aged garlic extract taken daily for 12 months, has been used. Also, a combination product containing 300 mg aged garlic extract, taken at a dose of four tablets daily for one year, has been used.
  • For colon cancer and rectal cancer: Capsules containing 2.4 mL of aged garlic extract taken daily for 12 months have been used.
  • For high cholesterol: A dose of 1000 mg to 7200 mg of a specific aged garlic extract (Kyolic, Wakanuga) has been used daily in divided doses for 4-6 months. A dose of 600 mg to 900 mg of a specific garlic powder tablet (Kwai, Lichtwer Pharma) has been taken daily in two or more divided doses for 6-16 weeks. Also, 300 mg of another specific garlic powder product (Garlex, Bosch Pharmaceuticals) taken twice daily for 12 weeks has been used. Also, 1200 mg of garlic powder plus 3 grams of fish oil daily for 4 weeks, or 500 mg of garlic oil plus 600 mg of fish oil daily for 60 days, has been used.
  • For high blood pressure: 300-1500 mg of garlic tablets taken in divided doses daily for 24 weeks has been used. 2400 mg of a specific garlic powder tablet (Kwai, Lichtwer Pharma) taken as a single dose or 600 mg daily for 12 weeks has been used. Capsules containing 960 mg to 7.2 grams of aged garlic extract, taken daily in up to three divided doses for up to 6 months, have been used. Specific products containing aged garlic extract include Kyolic (Garlic High Potency Everyday Formula 112, Wakunga/Wagner). 500 mg of garlic oil 500 mg plus 600 mg of fish oil daily for 60 days has been used.
  • For prostate cancer: 1 mg/kg of a water-soluble garlic extract, taken daily for one month, has been used.
  • For tick bites: Capsules containing 1200 mg of garlic taken daily for 8 weeks have been used.
APPLIED TO THE SKIN:
  • For fungal skin infections (ringworm, jock itch, athlete's foot): garlic ingredient ajoene as a 0.4% cream, 0.6% gel, and 1% gel applied twice daily for one week has been used. .

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