Which antibiotic class is associated with a high risk of tendon injury and QT prolongation?

Which antibiotic class is associated with a high risk of tendon injury and QT prolongation?

• A. Fluoroquinolones
• B. Macrolides
• C. Tetracyclines
• D. Aminoglycosides

Answer: (A)

Different antibiotic classes have distinct adverse effect profiles, and having both tendon injury and QT prolongation points to fluoroquinolones. Tendon toxicity, including tendinitis and potential rupture (notably of the Achilles tendon), is a well-known risk with fluoroquinolones, and it’s higher in older patients or when combined with corticosteroids. At the same time, fluoroquinolones can prolong the QT interval by affecting cardiac repolarization, increasing the risk of torsades de pointes in susceptible individuals or when combined with other QT-prolonging drugs or electrolyte disturbances. Other common classes don’t typically carry both of these risks together—their notable adverse effects tend to be different (for example, tetracyclines affect teeth and bone growth and photosensitivity, macrolides can prolong QT but aren’t associated with tendon injury, and aminoglycosides mainly cause nephro- and ototoxicity). Thus, fluoroquinolones best explain the combination of tendon injury risk and QT prolongation.

Different antibiotic classes have distinct adverse effect profiles, and having both tendon injury and QT prolongation points to fluoroquinolones. Tendon toxicity, including tendinitis and potential rupture (notably of the Achilles tendon), is a well-known risk with fluoroquinolones, and it’s higher in older patients or when combined with corticosteroids. At the same time, fluoroquinolones can prolong the QT interval by affecting cardiac repolarization, increasing the risk of torsades de pointes in susceptible individuals or when combined with other QT-prolonging drugs or electrolyte disturbances. Other common classes don’t typically carry both of these risks together—their notable adverse effects tend to be different (for example, tetracyclines affect teeth and bone growth and photosensitivity, macrolides can prolong QT but aren’t associated with tendon injury, and aminoglycosides mainly cause nephro- and ototoxicity). Thus, fluoroquinolones best explain the combination of tendon injury risk and QT prolongation.