Wednesday, November 5, 2014

No heart patient should take antibiuotics without supervision: Dr K K Aggarwal

Antibiotic Cotrimoxazole when Combined With ACE Inhibitor or ARB can end up with Sudden Death

Trimethoprim-Sulfamethoxazole May Increase Risk for Hyperkalemia in the Elderly

New Delhi: In a study published in BMJ, the risk of sudden death went up by more than a third in older patients taking ACE inhibitors or angiotensin-receptor blockers (ARBs) who were also put on the antibacterial agent cotrimoxazole (sulfamethoxazole and trimethoprim), compared with those who were instead given amoxicillin.

The elevated risk was likely caused by its capacity for raising serum potassium, which became fatal on top of other medications known for causing hyperkalemia.

Patients who are on ACE inhibitors or ARBs, are at risk for hyperkalemia, should not take any antibiotic without medical supervision.

If given

1. One should give it at the lowest dose and for a minimum period of time
2. And keep a watch on potassium.

Diabetics are vulnerable

Patients with type 2 diabetes have a tendency for hyperkalemia because od silent kidny involvement
Heart failure patients if on potassium-sparing spironolactone are also at risk
Patients with both reduced left ventricular function and diabetes have the greatest risk.

The risk, he said, depends on the antibiotic's dosage and duration of use. Ten days of cotrimoxazole may be risky while three days not.
In the study data from patients aged 66 or older who received ACE inhibitors or ARBs in Ontario from 1994 to 2012, identified outpatients who died of sudden death within 7 days of being prescribed cotrimoxazole, amoxicillin, ciprofloxacin, norfloxacin, or nitrofurantoin. Those 1027 cases were matched to 3733 controls alive within that time frame relative to the antibiotic prescriptions, based on, among other things, age, sex, chronic kidney disease, and diabetes.

The adjusted odds ratios (95% CI) for sudden death within 7 days of an antibiotic prescription on top of an ACE inhibitor or ARB, by antibiotic, relative to amoxicillin (which does not pose a hyperkalemia risk itself or prolong the QT interval) were: 1.38 for cotrimoxazole; 1.29 for ciprofloxacin; 0.74 for norfloxacin and 0.64 for nitrofurantoin.

Ciprofloxacin can predispose to sudden death by prolonging the QT interval.

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