These medications are used for controlling blood sugar in adult-onset diabetes.
Drugs in this family include:
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.
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
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 supplements might increase the absorption of chlorpropamide (and, by inference, other oral hypoglycemics), possibly requiring you to reduce your dose.4
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:
Weaker evidence suggests that the following herbs and supplements could potentially have the same effect under certain circumstances:
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.
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.
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.
1. Adams JF, et al. Malabsorption of vitamin B 12 and intrinsic factor secretion during biguanide therapy. Diabetologia 24:16-18, 1983.
2. Kishi T, et al. Bioenergetics in clinical medicine. XI. Studies on CoQ and diabetes mellitus. J Med 1976;7: 307-321.
3. Monostory K, et al. Ipriflavone as an inhibitor of human cytochrome P450 enzymes. Br J Pharmacol. 1998;123: 605-610.
4. Pronsky Z, ed. Powers and Moore's food medication interactions. 10th ed. Pottstown, PA: Food-Medication Interactions; 1997:60.
5. A to Z Drug Facts [book on CD-ROM]. 2nd ed. St. Louis, MO: Facts and Comparisons; 2000.
6. Hodgson JM, Watts GF, Playford DA, et al. Coenzyme Q(10) improves blood pressure and glycaemic control: a controlled trial in subjects with type 2 diabetes. Eur J Clin Nutr. 2002;56:1137-1142.
7. Singh RB, Niaz MA, Rastogi SS, et al. Effect of hydrosoluble coenzyme Q10 on blood pressures and insulin resistance in hypertensive patients with coronary artery disease. J Human Hypertens. 1999;13:203-208.
8. Sugiyama T, Kubota Y, Shinozuka K, et al. Ginkgo biloba extract modifies hypoglycemic action of tolbutamide via hepatic cytochrome P450 mediated mechanism in aged rats. Life Sci. 2004;75:1113-1122.
Kudolo GB, Wang W, Elrod R, et al. Short-term ingestion of Ginkgo biloba extract does not alter whole body insulin sensitivity in non-diabetic, pre-diabetic or type 2 diabetic subjects-A randomized double-blind placebo-controlled crossover study. Clin Nutr. 2005 Nov 14. [Epub ahead of print]
10. Kudolo GB, Wang W, Javors M, et al. The effect of the ingestion of Ginkgo biloba extract (EGb 761) on the pharmacokinetics of metformin in non-diabetic and type 2 diabetic subjects-A double blind placebo-controlled, crossover study. Clin Nutr. 2006 May 12. [Epub ahead of print]
11. Ting RZ, Szeto CC, Chan MH, et al. Risk factors of vitamin B12 deficiency in patients receiving metformin. Arch Intern Med. 2006;166:1975-1979.
Last reviewed August 2013 by EBSCO CAM Review Board Last Updated: 8/22/2013