Goat’s Rue Safe for Long Term Use?

I read that Goat’s Rue is toxic to the liver in the link below?   Is it safe to use long term for a type 2 diabetic?

1 answer

I think you may have pretty well answered your own question, as indicated in several of the references that you kindly provided in the attached article.
The active ingredient in goat’s rue (gallega oficinalis) is guanidine. As the article you sent summarized, “While guanidine-containing supplements have glucose-lowering properties, the toxicity profile outweighs any potential benefits provided and should not generally be used or recommended.”
Phenformin was a previously-available pharmaceutical derivative of goat’s rue which was removed from the US market in the late 1970s due to excess deaths from lactic acidosis. It was not until the mid-90s that another biguanide, Metformin, was introduced in the US. Metformin is much safer than phenformin, and has much less tendency (if any) to cause lactic acidosis (although lactic acidosis is still listed as an adverse effect of Metformin in the product literature).
Metformin has been used with an excellent safety record for over 75 years (it’s been available in Europe since the 1950s). In the Diabetes Prevention Program Research group’s study, over 18,000 patient-years of follow-up has accrued, with about 20% of the cohort now 70 or older. There have been no cases of lactic acidosis or significant hypoglycemia.1
I’ve used both goat’s rue and metformin in my patients. Metformin is cheaper, safer, and far more effective than goat’s rue. This is one drug that is superior to its
herbal prototype. For once, the pharmaceutical companies got it right.
Despite the erroneous beliefs of many physicians, Metformin is neither nephrotoxic nor hepatotoxic, and can be safely used even in those with severely impaired kidney and liver function. Just titrate the dose down to whatever fractional dose the patient can tolerate, however. I had a diabetic patient who came to me on insulin, with a GFR (glomerular filtration rate) of 15! His nephrologist was recommending dialysis. After discontinuing insulin, and initiating a very low dose of metformin, his GFR began to climb (improve), his other labs got better, and his nephrologist took him off the “critical list.”
I would not waste time fooling with goat’s rue, and recommend your mother include Metformin in her regimen.
Ward Dean, MD

  1. The Diabetes Prevention Program Research Group. Long-Term Safety, Tolerability, and Weight Loss Associated with Metformin in the Diabetes Prevention Program Outcomes Study. Diabetes Care 2012 Apr; 35(4): 731-737.

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