Wednesday, November 26, 2008

More on Fluoroquinolone Related Tendon Injuries

The Medical Letter is an excellent source for information about medications. It is independent and thus not funded by the pharmaceutical industry. In addition, it appears to have no political agenda or bias, such as the FDA for example that might err on the side of caution and/or informing the public based on recent scrutiny or Public Citizen's Best Pills Worst Pills which is pretty blatantly anti-industry. It is the closest thing to a Consumer Reports for drugs that we have. It is a subsription based service, so you will have to pay if you want to read their evaluations.

However, I (hopefully legally) copied some of their statements on the issue of fluoroquinolone-related tendon injury because my post on Tendon rupture with Cipro? FDA caves to Public Citizen has been the my blog's most responded to and "hit" post. I initially complained that the FDA was adding a boxed warning without giving physicians any real data on actually risks. In my opinion it seemed to caving in to public and political pressure. However, the vast number of responses I received seem to indicate their may actually be more to the story. I would be nice if the FDA would release all the data behind their boxed warnining. However, The Medical Letter has done their own research and commented.

Fluoroquinolone-related tendon injury is rare; estimates for its incidence in
the general population range from 0.14% to 0.4%. The risk is higher for patients
>60 years old and for those taking corticosteroids. For patients with organ
transplants, the incidence may be as high as 15%. A case-control study in Italy
involving 22,194 cases of non-traumatic tendinitis and 104,906 controls found
that fluoroquinolone use was significantly associated with tendon disorders in
general (OR 1.7; 95% CI 1.4-2.0), tendon rupture (OR 1.3; 95% CI 1.0-1.8), and
Achilles tendon rupture (OR 4.1; 95% CI 1.8-9.6). Achilles tendon rupture
occurred with fluoroquinolone treatment in one of every 5989 patients in general
and in one of every 1638 patients >60 years old. Widespread use of
fluoroquinolones, particularly for treatment of respiratory infections, has
produced substantial bacterial resistance to this class of drugs and
has been
associated with an increase in the incidence and severity of Clostridium
difficile disease. Even when bacterial pneumonia is considered a likely
possibility, other drugs are generally preferred, at least in non-elderly,
otherwise healthy patients.

This kind of information is much more helpful then either FDA's boxed warning or Public Citizen's rant, mainly because it uses several sources of data. Fluorquinolones can be useful drugs, but based on all the current information, they really should only be used if equal or better options do not exist, especially for elderly patients.


Unknown said...

Interesting article. I'd never heard of the Medical Letter.

You may also be interested in a site that lets you search adverse events reported to the FDA.

e.g., here's a search for AEs reported for Levaquin that also reported Tendon Rupture:

Anonymous said...

I, for one, am thankful for the boxed warning (although I do usually read all my prescription facts before taking anything).

Unbeknownst to my doctor, I'm a runner and was planning to ramp up training for a half-marathon when I was prescribed Cipro. Seeing the warning made me think twice. Even if musculoskeletal side effects are rare, increasing my level of weight-bearing and impact-inducing exercise while on the drug seems to be asking for trouble.

I'm allergic to sulfa, but certain there would have been better alternatives. I think my doctor chose Cipro because it's super-cheap, but I'd have gladly paid more not to worry and plan to avoid Cipro in the future.

Anonymous said...

. . . . except that fluoroquinolone tendon injuries occur months and years after finishing a prescription and are more often than not unrecognized by medicine or reported by medicine - a study like this is only as good as the reporting - which is inadequate. Many patients won't remember what antibiotic they took or be aware that FQs can injure tendons - any tendon, not just the achilles . . and most doctors are not going to sift through a patient's charts and look for an FQ in their history