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garlic (Allium Sativum)

Indications: (uses) 1) hypertension - does not significantly lower blood pressure [6] - possibly effective, weak evidence [10] - aged black garlic with S-allyl-L-cysteine lowers diastolic blood pressure (6 mm Hg), especially in men with moderate hypercholesterolemia [11] 2) hyperlipidemia - does not lower LDL cholesterol [5] 3) may reduce risk of some cancers [4] a) prostate cancer b) stomach cancer c) colorectal cancer Contraindications: 1) history of hypoglycemia 2) anticoagulation therapy 3) antiplatelet therapy 4) thrombocytopenia Dosage: - 1 glove of fresh garlic twice a day - discontinue 7 days before surgery [7] Adverse effects: 1) garlic breath (halitosis) 2) reports of bleeding with surgery 3) hypoglycemia [7] 4) GI upset, heartburn (pyrosis) [7] Drug interactions: 1) may increase effects of anti-hyperlipidemic agents 2) may increase effects of hypoglycemic agents 3) may increase effects of antihypertensive agents 4) anticoagulants in combination may increase risk of hemorrhage - no interaction with warfarin [8,9] - may interact with warfarin [10] 5) antiplatelet agents including NSAIDs [7] - in vitro effects on platelet aggregation [8] 6) garlic supplements may enhance metabolism & diminish saquinavir levels by 50% [2] - other protease inhibitors, i.e. Agenerase, Crixivan, Norvir & Viracept may also interact with garlic 7) may interact with non-nucleoside reverse transcriptase inhibitors [10] 8) may interact with isoniazid [10] Mechanism of action: 1) contains allicin which potentially a) inhibits angiotensin 2 b) causes vasodiation c) but it does not significantly lower blood pressure [6] 2) allegedly lowers cholesterol & triglycerides a) does not significantly lower total serum cholesterol [10] b) does not significantly lower LDL cholesterol [5] 3) may have antibacterial & antifungal properties 4) may have anti-thrombotic properties 5) may have anti-inflammatory properties 6) some anti-cancer properties

General

pharmaceutical herb; medicinal herb; herbal supplement; botanical

References

  1. Kaiser Permanente, Northern California, Pharmacy update
  2. Prescriber's Letter 8(3):17 2001
  3. Prescriber's Letter 10(2):12 2003
  4. Prescriber's Letter 10(6):35 2003
  5. Prescriber's Letter 14(4): 2007 Garlic stinks at Lowering LDL Detail-Document#: 230409 (subscription needed) http://www.prescribersletter.com - Gardner CD et al, Effect of raw garlic supplements on plasma lipid concentrations in adults with moderate hypercholesterolemia: a randomized controlled trial. Arch Intern Med 2007, 167:346 PMID: 17325296
  6. Prescriber's Letter 15(10): 2008 Garlic for Lowering Blood Pressure Detail-Document#: 241076 (subscription needed) http://www.prescribersletter.com
  7. Geriatrics at your Fingertips, 13th edition, 2011 Reuben DB et al (eds) American Geriatric Society
  8. Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013
  9. Mohammed Abdul MI1, Jiang X, Williams KM et al Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects. Br J Pharmacol. 2008 Aug;154(8):1691-700. PMID: 18516070
  10. Medical Knowledge Self Assessment Program (MKSAP) 17, 18. American College of Physicians, Philadelphia 2015, 2018
  11. Swift Yasgur B Aged Black Garlic Supplement May Help Lower BP. Medscape. April 15, 2022 https://www.medscape.com/viewarticle/972256 - Valls RM, Companys J, Calderon-Perez L et al Effects of an Optimized Aged Garlic Extract on Cardiovascular Disease Risk Factors in Moderate Hypercholesterolemic Subjects: A Randomized, Crossover, Double-Blind, Sustainedand Controlled Study. Nutrients. 2022. Jan 18;14(3):405 PMID: 35276764 PMCID: PMC8838962 Free PMC article https://www.mdpi.com/2072-6643/14/3/405

Component-of

garlic/inositol/policosanol garlic/phosphatidylcholine garlic/soybean lecithin