What are beta-blockers? How do they interact with other drugs?

Coenzyme Q10 (CoQ10)

Effect: Supplementation Possibly Helpful

There is some evidence that beta-blockers (specifically
propranolol, metoprolol, and alprenolol) might impair the body’s ability to
utilize the substance CoQ10. This is particularly of concern, because
CoQ10 appears to play a significant role in normal heart function.
Depletion of CoQ10 might be responsible for some of the side effects of
beta-blockers. In one study, CoQ10 supplements reduced side effects
caused by the beta-blocker propranolol. The beta-blocker timolol may interfere
with CoQ10 production to a lesser extent than other beta-blockers.

Chromium

Effect: Possible Helpful Interaction

Beta-blockers have been known to reduce levels of HDL (good) cholesterol.
According to one study, chromium supplementation can offset
this adverse effect.

Coleus forskohlii

Effect: Theoretical Interaction

The herb Coleus forskohlii relaxes blood vessels and might
have unpredictable effects on blood pressure if combined with
beta-blockers.

Bibliography

Folkers, K. “Basic Chemical Research on Coenzyme Q10 and Integrated Clinical Research on Therapy of Diseases.” In Coenzyme Q: Biochemistry, Bioenergetics, and Clinical Applications of Ubiquinone, edited by G. Lenaz. New York: John Wiley & Sons, 1985.

Hamada, M., et al. “Correlation Between Serum Coq10 Level and Myocardial Contractility in Hypertensive Patients.” In Biomedical and Clinical Aspects of Coenzyme Q, Vol. 4, edited by K. Folkers. Amsterdam: Elsevier Science, 1984.

Roeback, J. R., et al. “Effects of Chromium Supplementation on Serum High-density Lipoprotein Cholesterol Levels in Men Taking Beta-blockers.” Annals of Internal Medicine 115 (1991): 917-924.