Drug Interactions:
Oral Hypoglycemics

These medications are used for controlling blood sugar in adult-onset diabetes.

Drugs in this family include

• acarbose (Prandase, Precose)
• acetohexamide (Dymelor)
• chlorpropamide (Diabinese)
• glimepiride (Amaryl)
• glipizide (Glucotrol, Glucotrol XL)
• glyburide or glibenclamide (DiaBeta, Glynase, Micronase)
• metformin (Glucophage)
• miglitol (Glyset)
• phenformin
• pioglitazone (Actos)
• rosiglitazone (Avandia)
• repaglinide (Prandin)
• tolazamide (Tolinase)
• tolbutamide (Orinase)
• troglitazone (Rezulin)
• and others

Vitamin B12

Supplementation Possibly Helpful

The so-called biguanide oral hypoglycemic drugs, metformin and phenformin, are thought to cause malabsorption of vitamin B₁₂.¹ Taking extra vitamin B₁₂ should solve this problem.

Coenzyme Q10 (CoQ10)

Supplementation Possibly Helpful

Studies suggest that the oral hypoglycemic drugs glyburide, phenformin, and tolazamide may inhibit the normal production of the substance coenzyme Q₁₀ (CoQ₁₀).² While there is as yet no direct evidence that taking extra CoQ₁₀ will provide any specific benefit, supplementing with CoQ₁₀ on general principle might make sense.

Ipriflavone

Might Require Reduction in Medication Dosage

There is some evidence that the supplement ipriflavone might increase blood levels of oral hypoglycemic drugs. This could lead to a risk of blood sugar levels falling too low. If you are taking oral hypoglycemic medications, don't take ipriflavone without first consulting your physician.³

Magnesium

Might Require Reduction in Medication Dosage

Magnesium supplements might increase the absorption of chlorpropamide (and, by inference, other oral hypoglycemics), possibly requiring you to reduce your dose.⁴

Herbs and Supplements

Might Require Reduction in Medication Dosage

Meaningful preliminary evidence suggests that use of the following herbs and supplements could potentially improve blood sugar control and require you to reduce your daily dose of oral hypoglycemic medication: aloe, chromium, fenugreek, ginseng, gymnema, and vanadium.

Weaker evidence suggests that the following herbs and supplements could potentially have the same effect under certain circumstances: Anemarrhena asphodeloides,arginine, Azadirachta indica (neem), bilberry leaf, biotin, bitter melon, carnitine, Catharanthus roseus, Coccinia indica,coenzyme Q₁₀, conjugated linoleic acid (CLA), Cucumis sativus, Cucurbita ficifolia, Cuminum cyminum (cumin), Euphorbia prostrata,garlic, glucomannan, Guaiacum coulteri, Guazuma ulmifolia,guggul, holy basil, Lepechinia caulescens,lipoic acid, Medicago sativa (alfalfa), Musa sapientum L. (banana), niacinamide, nopal cactus, onion, Phaseolus vulgaris, Psacalium peltatum, pterocarpus, Rhizophora mangle,salt bush, Spinacea oleracea, Tournefortia hirsutissima, Turnera diffusa, and vitamin E.

Potassium Citrate

Possible Harmful Interaction

Potassium citrate and other forms of citrate (e.g., calcium citrate, magnesium citrate) may be used to prevent kidney stones. These agents work by making the urine less acidic.

This effect on the urine may lead to decreased blood levels and therapeutic effects of chlorpropamide and possibly other oral hypoglycemic drugs.⁵

For this reason, it may be advisable to avoid these citrate compounds during treatment with oral hypoglycemic drugs.

Dong Quai, St. John's Wort

Possible Harmful Interaction

Some oral hypoglycemic drugs have been reported to cause increased sensitivity to the sun, amplifying the risk of sunburn or skin rash. Because St. John's wort and dong quai may also cause this problem, taking these herbal supplements during treatment with oral hypoglycemic drugs might add to this risk.

It may be a good idea to wear a sunscreen or protective clothing during sun exposure if you take one of these herbs while using an oral hypoglycemic medication.

Last reviewed March 2002 by Medical Review Board

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