Monday, November 03, 2014


Hypertension is a growing problem amongst the Malaysian population. ACEI and ARBs are commonly used as they are proven to be very effective in the treatment of hypertension and also confers additional benefits with respect to renal protection.
"Flu", cough and cold is also a very common ailment afflicting us Malaysians. Co-trimoxazole ( commonly called Bactrim ) is also a commonly used antibiotic for treatment of common infective disorders.
There were some reported deaths in people taking Bactrium, who were also hypertensives on ACE-I. So the Canadian Researches looked into this issue. This resulted in a paper published in the BMJ 30th Oct issue. The paper is entitled, " Co-trimoxazole and sudden cardiac deaths in patients taking inhibitors of Renin Angiotensin system.". The study was led by Dr Michael Fralich From the Canadian Drug Safety and Effectiveness Research Center. They review the hospitalisation data and discharged data of the Ontario Health District from 1st April 1994 till 1st Jan 2012. There were all together 39,879 sudden cardiac deaths. They analysed those who had received ACEI / ARB  and also antibiotics Co-trimoxazole and also ciprofloxacin and two other antibiotics. These SCD were matched against 3,733 patients of the same age and sex group and who also have the same co-morbid factors of T2DM and kidney disease. These were used as matched controls.

Table 3 
 Antibiotic use and risk of sudden death within 14 days
Antibiotic useNo (%) casesNo (%) controlsOdds ratio (95% CI)Adjusted odds ratio (95% CI)*
Amoxicillin (reference)418 (22.9)2021 (29.8)1.0 (reference)1.0 (reference)
Co-trimoxazole474 (25.9)1262 (18.6)1.80 (1.54 to 2.09)1.54 (1.29 to 1.84)
Ciprofloxacin603 (33.0)1888 (27.9)1.50 (1.30 to 1.72)1.18 (1.00 to 1.39)
Norfloxacin158 (8.6)832 (12.3)0.89 (0.73 to 1.09)0.83 (0.65 to 1.05)
Nitrofurantoin174 (9.5)768 (11.3)1.08 (0.88 to 1.32)1.03 (0.81 to 1.30)
*Analysis adjusted for disease risk index.

They found that those taking Co-trimoxazole and also an ACEI / ARB had a significantly higher SCD rate than match controls, especially if used till 14 days.  Ciprofloxacin also carries a slightly increase SCD rate, though not as high as Co-trimoxazole.
The reason for this may be the effect of Co-trimoxazole to increase serum potassium is some people.
There were earlier evidence that the use of ciprofloxacin was associated with a risk of SCD.

I suppose the message should be that when we use ACE-I / ARB, we should beware of the problem of hyper-kalemia and we should also be careful of antibiotics used. Co-trimoxazole use should be restricted to patients not taking ACE-I / ARB.


Danny Yap Hsiong Eng said...

yeah bactrim bind to ENac channel, thus doesn't allow the influx of sodium ions into the principal cells in collecting duct. As a result, no efflux of hydrogen ion and potassium ion into the tubule.

Winston Yap said...

Doc, I just checked the Internet for drug-drug interaction for Lofral 5 (amlodipine) and found more than five hundred drugs interact with amlodipine!!
This was found in
With such a vast number of drug interactions, isn't it dangerous to take amlodipine?
Thank you.