The FDA has announced that fluoroquinolone antimicrobial drugs, like Levaquin and Cipro, will now carry the agency’s strictest warning. Antimicrobial drugs are used to treat or prevent certain types of serious bacterial infections, including pneumonia.

The risk of developing fluoroquinolone-associated tendinitis and tendon rupture is further increased in people older than 60, in those taking corticosteroid drugs, and in kidney, heart, and lung transplant recipients. Patients experiencing pain, swelling, inflammation of a tendon or tendon rupture should be advised to stop taking their fluoroquinolone medication and to contact their health care professional promptly about changing their antimicrobial therapy. Patients should also avoid exercise and using the affected area at the first sign of tendon pain, swelling, or inflammation.

The FDA also notified drug manufacturers that a Medication Guide should now be provided with this class of medication to ensure that patients understand the risks that they may be exposed to. The agency advised physicians that caution should be exercised when prescribing fluoroquinolones and said that each patient’s risk should be evaluated on a case-by-case basis.