Vitamin B 12

Supplementation Possibly Helpful

The biguanide oral hypoglycemic drugs, metformin and phenformin, can cause malabsorption of vitamin B ₁₂ . 1 In turn, this can lead to vitamin B ₁₂ deficiency. 11 Taking vitamin B ₁₂ supplements should easily solve this problem.

Coenzyme Q 10 (CoQ 10 )

Possible Benefits and Risks

Studies suggest that the oral hypoglycemic drugs glyburide, phenformin, and tolazamide may inhibit the normal production of the substance coenzyme Q ₁₀ (CoQ ₁₀ ). 2 While there is as yet no direct evidence that taking extra CoQ ₁₀ will provide any specific benefit, supplementing with CoQ ₁₀ on general principle might make sense.

In addition, there is some evidence that use of CoQ ₁₀ could improve blood sugar control for people with diabetes. While this could be helpful, keep in mind that if it works, you might need to reduce your medication dosage. 6-7

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

Potassium Citrate

Possible Harmful Interaction

Potassium citrate and other forms of citrate (eg, 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.

Gingko Biloba

Possible Harmful Interactions

It has been suggested that ginkgo might cause problems for people with type 2 diabetes both by altering blood levels of medications as well as by directly affecting the blood sugar-regulating system of the body. 8 However, the most recent and best designed studies have failed to find any such actions. 9-10 Nonetheless, until this situation is clarified, people with diabetes should use ginkgo only under physician supervision.

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.