COPD and IV Magnesium

I disagree

 

Today I gave a COPD patient Magnesium sulphate IV. My consultant said, ”There’s no evidence of benefit…. Don’t do it.” I didn’t argue: Mondays are too busy for these kinds of arguments.

 

There is evidence that Magnesium:

 

• acts as a bronchodilator
• that it improves clinical outcomes in severe asthma not responding to inhaled beta-agonists
• is safe (LD50 in rats is 1200mg/kg)

 

We know that the following patients have reduced intracellular magnesium:

 

• those with severe chronic disease
• those who take long-term corticosteroids
• those who take inhaled beta-agonists
• those on diuretics
• those with abnormalities of potassium and/or calcium metabolism
• those with diabetes
• the very elderly
• those on chemotherapy
• those with eating disorders
• those with alcohol dependence disorders
• those with severe COPD

 

We know from the law of diminishing returns that those most severely affected by disease benefit most from its treatment and that harms and benefits have different curves that cross at different points for all patients.

 

We also know that “no evidence of benefit” is not evidence of no benefit. We lack data.

In COPD, we know that combination therapy acts synergistically and that steroids and antibiotics for acute exacerbations improve outcomes (even in patients without evidence of bacterial infection).

 

My patient had severe COPD: she had had multiple admissions this year, had suffered respiratory arrest more than once and was already on maximal therapy before her acute presentation. Did my patient benefit from the IV Magnesium sulphate? Probably. Can I prove it? No, but neither can it be proven that she did not benefit.