[e-drug] Metformin and Lactic acidosis (3)

["Amani Phillip" <amaniphillip@yahoo.com>]

E-DRUG: Metformin and Lactic acidosis (3)
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Dear E-druggers,

It has been postulated that metformin may elevate lactate levels as a result of inhibiting gluconeogenesis. In addition a reduced renal function may also be associated with accumulation of metformin, which may result in lactic acidosis.  Dosage adjustment in patients with moderate renal impairment is therefore recommended. Metformin is not recommended in patients with severe renal impairment. The dosage adjustment should be done cautiously as this may lead to sub therapeutic dose.

However, the association of metformin and lactic acidosis has also been questioned. As you may be aware, lactic acidosis may result from other factors such as cardiovascular diseases, respiratory disorders, drugs, etc. Some of these conditions/factors were also present in the patients on metformin who had lactic acidosis. I'm not aware of any study that excluded all these confounded factors. It might not be practical/ethical! 

Therefore, till we have more light in the subject, the current protocols (dosage adjustment?) are recommended when using metformin in patients with renal impairment. 

Best regards,

Amani Phillip, MPharm-Clin Pharm(Perth), BPharm(Dar)
Clinical Pharmacist and Head,
Pharmacist Assistant Training Course,
National Health Training Center,
Windhoek
Namibia