Rx Combo May Trigger Serious Reactions

Clarithromycin combined with statins tied to rhabdomyolysis, hyperkalemia and acute kidney injury

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Some things just don't mix — and that applies to medications. One antibiotic combined with statins may be dangerous. Fortunately, other types of antibiotics may be safer when mixed with statins.

A new study found that older people who take the common antibiotic clarithromycin (brand name Biaxin) combined with certain statins may be slightly more likely to be admitted to the hospital than those taking azithromycin (brand name Zithromax), another popular antibiotic.

This research was performed by Amit X. Garg, MD, a nephrologist at Western University in London, Canada, and colleagues.

“To prevent toxicity [of statins], the use of azithromycin or another antibiotic that does not interact with statins can be considered,” Dr. Garg and team wrote.

Millions of people take cholesterol-lowering statins to prevent heart disease. For most who use statins, the medications do not cause any serious ill effects.

Dr. Garg and colleagues studied existing data on 104,041 statin users in Ontario, Canada, between 2002 and 2013. Patients were 66 years old or older, with an average age of 74. They had been prescribed the statin rosuvastatin (brand name Crestor), pravastatin (brand name Pravachol) or fluvastatin (brand name Lescol).

Past studies indicated that these types of statins were safer than others to take with clarithromycin.

A total of 51,523 research subjects in this study were prescribed clarithromycin in addition to statins. Another 52,518 were taking azithromycin. Azithromycin is also an antibiotic, often prescribed for infection of the ears, lungs, sinuses, skin and throat.

Dr. Garg and team assessed outcomes within 30 days of the patient starting the co-prescription of the antibiotic.

Some statin users develop rhabdomyolysis, a condition that causes muscle cells to break down, reports the Mayo Clinic. In this study, 13 of those taking clarithromycin were hospitalized with rhabdomyolysis — compared to six azithromycin users.

Dr. Garg and colleagues also found that a total of 175 patients taking clarithromycin were hospitalized with acute kidney injury — compared to 122 in the azithromycin group.

In the clarithromycin group, 33 were hospitalized with hyperkalemia — compared to 18 azithromycin users. Hyperkalemia is a condition where potassium rises to a higher-than-normal level in the blood.

Overall, 200 of the clarithromycin patients and 155 azithromycin patients had fatal complications.

“Co-prescription of clarithromycin versus azithromycin was associated with a modest but statistically significant increase in the 30-day absolute risk of adverse outcomes,” Dr. Garg and team wrote.

This study was published Dec. 22 in CMAJ.

The Institute for Clinical Evaluative Sciences Western funded this research. Some study authors disclosed ties to AstraZeneca, Bristol-Myers Squibb, Eli Lilly and Co., GlaxoSmithKline, Hoffman–La Roche, Novartis, Novo Nordisk and Pfizer.

Review Date: 
December 21, 2014
Last Updated:
December 23, 2014