garlic

Complementary/Alternative Medicine: This monograph describes a natural or herbal product that is not subject to FDA guidelines for medicines. Patients and clinicians are advised to read package labels carefully to ensure safe and efficacious use.

REMS

PO: Hypertension, hyperlipidemia, cardiovascular disease prevention, colorectal and gastric cancer prevention
Topical Dermal fungal infections including tinea corporis, cruris, and pedis.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Bleeding disorders. Discontinue use 1–2 wk prior to surgery.

Use Cautiously in:

Diabetes, gastrointestinal infection or inflammation.

Adv. Reactions/Side Effects ⬆ ⬇

CNS: dizziness

GI: bad breath, diarrhea, flatulence, Irritation of the mouth, esophagus, and stomach, nausea, vomiting

Derm: Contact dermatitis and other allergic reactions (asthma, rash, anaphylaxis [rare]), Diaphoresis

Hemat: Chronic use or excessive dose may lead to ↓ hemoglobin production and lysis of RBCs, platelet dysfunction, prolonged bleeding time

Misc: body odor

Interactions ⬆ ⬇

Natural-Drug Products:

Use of garlic with anticoagulants, antiplatelet agents, and thrombolytics may ↑ risk of bleeding.
May ↓ the effectiveness of contraceptive drugs and cyclosporine.
May ↓ plasma concentrations of saquinavir, nevirapine, delavirdine, and efavirenz.
May ↓ isoniazid levels by 65%.

Natural-Natural Products:

Herbs with anticoagulant or antiplatelet properties may increase bleeding risk when combined with garlic, including: angelica, anise, asafoetida, bogbean, boldo, capsicum, celery, chamomile, clove, danshen, dong quai, fenugreek, feverfew, ginger, ginkgo, Panax ginseng, horse chestnut, horseradish, licorice, meadowsweet, papain, passionflower, poplar, prickly ash, onion, quassia, red clover, turmeric, wild carrot, wild lettuce, willow, and others.

Availability ⬆ ⬇

Capsules: ^OTC
Tablets: ^OTC
Topical cream:
Topical gel:
Fresh garlic: ^OTC

Route/Dosage ⬆ ⬇

PO (Adults ): 200–400 mg tid of standardized garlic powder extract with 1.3% allin. Fresh garlic: 1–7 cloves per day. One clove contains approximately 4 g of garlic.
(Adults ): Tinea infections: 0.4% cream, 0.6% gel, or 1% gel applied bid x 7 days.

US Brand Names ⬆ ⬇

Alli sativa bulbus, Allium sativum

Action ⬆ ⬇

May have HMG-CoA inhibitor properties in lowering cholesterol, but less effectively than statin drugs; vasodilatory and antiplatelet properties.

Therapeutic effects:

Decreased cholesterol levels.
Decreased platelet aggregation.

Classifications ⬆ ⬇

Therapeutic Classification: lipid-lowering agents

Pharmacokinetics ⬆ ⬇

Absorption: Garlic oil is well absorbed.

Distribution: Unknown.

Metabolism/Excretion: Kidney and lungs.

Half-Life: Unknown.

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
PO	4–25 wk	unknown	unknown

Patient/Family Teaching ⬆ ⬇

Instruct patients about the need to follow a healthy diet (low in fat and high in vegetables and fruits) in conjunction with garlic. Other lipid-reducing strategies, such as exercise and smoking cessation, should also be employed.
Inform patients that there are other more effective agents for lipid reduction available.
Caution patients about the potential for bleeding and not to take this herbal remedy without notifying their health care provider if they are taking other medications. Instruct patients undergoing elective surgery to stop using garlic 2 wk prior to surgery and to notify the surgeon that they are taking garlic in the event of emergent surgery.
Notify patients that allergies may occur and to discontinue use if symptoms develop.
Emphasize the need for follow-up exams with a health care professional to assess effectiveness of the regimen.

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Indications ⬇