While penicillin and related antibiotics such as amoxicillin accounted for half the emergency visits, other classes of antibiotics such fluoroquinolones – the class that includes Cipro – and newer antibiotics accounted for the rest.

This was the first time a large scale study looked at antibiotic side effects in the U.S.To reach their conclusions, the authors of the study used the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project, a sample of 63 U.S. hospitals, between 2004 and 2006. According to their survey, the hospitals recorded more than 6,600 emergency visits that were due to an adverse reaction to an antibiotics. They were able to extrapolate this to the whole country and estimated that 142,000 such emergency visits are made every year.

“This number is an important reminder for physicians and patients that antibiotics can have serious side effects and should only be taken when necessary,” said the CDC’s Dr. Daniel Budnitz, who led the study.

Like hundreds of other people, Angell took a course of Cipro to prevent infection. A few days later, he felt pain in both his Achilles tendons. A week after that, the pain had grown so bad that he talked to a doctor, who switched him to another antibiotic. Unfortunately, the drug switch came too late.

Angell’s Cipro injury was so bad, that he became all but immobile for a time. He had to undergo rehab, and missed a great deal of work. He had to give up his staff director position, and now holds a much less senior job. Even today, Angell still walks with a cane and can’t hike or play tennis the way he used to.

Many patient advocates have argued that Cipro was overused during the anthrax scare in people like Angell, who did not actually develop an infection.

In 2002, four US postal workers from New Jersey – all of whom were exposed to anthrax – sued Bayer Corp. claiming the company failed to disclose data that Cipro could damage nerves and tendons. One of the plaintiffs, mail handler James Sherman said he developed pain in his elbows, knees and groin shortly after taking Cipro. “I later complained to the hospital,” Sherman told The Star-Ledger of Newark. “But now, I walk like I’m crippled all the time. I never had these aches and pain before.”

It was only last week that the FDA asked the makers of Cipro and similar antibiotics to add a black box warning about the risk of tendon ruptures to their labels. But the advocacy group Public Citizen raised the alarm about tendon damage more than a decade ago. In 1996, the group first petitioned the FDA for a tendon damage warning.The FDA that year granted the petition, but the warning was buried in the list of possible adverse reactions and proved inadequate.

In 2006, as reports of tendon damage linked to Cipro and its related antibiotics continued to grow, Public Citizen petitioned the FDA for a stronger black box warning.But the FDA never responded to that petition. This past January, Public Citizen sued the FDA to compel it to take action. With the lawsuit looming, the FDA finally took appropriate action to warn consumers of this dangerous Cipro side effect.

Last Tuesday, the US Food & Drug Administration (FDA) asked the makers of fluoroquinolone antibiotics to add the agency’s strictest safety warning to the product labels about their link to tendon damage. The FDA said that patients with the highest risk of problems included people over 60, those with kidney, heart and lung transplants, and those also taking steroids. Most of the tendon ruptures reported to the FDA involved the Achilles tendon. Ruptures of tendons in the rotator cuff, hand, biceps and thumb were also reported.

According to an article by the Associated Press, Health Canada said it will ask manufacturers of fluoroquinolones to include a “box warning” on the product monographs alerting people who take the drugs of the fact they may be at higher risk of tendon ruptures. In an email to the Associated Press spokesperson Alastair Sinclair, said that “tendonitis, tendon disorder, and tendon rupture are known adverse reactions for quinolones.”

In addition to Cipro, the drugs levofloxacin (Levaquin), norfloxacin (Noroxin), ofloxacin (Floxin), gemifloxacin (Factive) and moxifloxacin (Avelox) will be subject to the new Canadian warning.

According to the FDA, tendon ruptures generally related to the use of fluoroquinolones involve the Achilles tendon as well as ruptures of the shoulder, hand, biceps, and thumbs. Tendons are the areas that connect your muscles to your joints. The Achilles tendon is at the back of the ankle. The risk of tendonitis and tendon rupture linked to drugs such as Cipro is “especially increased” in patients older than 60, as well as those who have received kidney, heart, or lung transplants and people on “concomitant” steroid therapy.

The FDA warns that physicians “should advise patients, at the first sign of tendon pain, swelling, or inflammation—symptoms that typically precede tendon rupture and tendonitis—to stop taking the fluoroquinolone, to avoid exercise and use of the affected area, and to promptly contact their doctor about changing to a non-fluoroquinolone antimicrobial drug.”

Other antibiotics that will now bear a similar black box warning include gemifloxacin, marketed as Factive; levofloxacin, marketed as Levaquin; moxifloxacin, marketed as Avelox; norfloxacin, marketed as Noroxin; and ofloxacin, marketed as Floxin and generic ofloxacin.

From November 1997 through December 2005, the FDA received 262 reports of tendon ruptures, mainly of the Achilles tendon, 258 cases of tendinitis and 274 cases of other tendon disorders in patients using fluoroquinolone antibiotics. An additional 74 tendon ruptures had subsequently been reported to the FDA for a total of 336. But Public Citizen contends that only a small fraction of cases are typically reported to the FDA, so the actual number of ruptures and other tendon injuries attributable to the antibiotic is probably much higher.

“While the FDA sits idly by and ignores the problem, more people will suffer serious tendon ruptures that could have been prevented,” said Dr. Sidney Wolfe, director of Public Citizen’s Health Research Group said at the time. “The current warning is buried in a long list of possible adverse reactions and is far too easy to miss.

The lawsuit was filed in the U.S. District Court for the District of Columbia. Public Citizen said in its complaint that by failing to act upon petition, the FDA was violating the Administrative Procedure Act.

A 2002 article in the Palm Beach Post reported that some American Media employees – whose offices were targeted in the anthrax attacks – reported health problems months after taking Cipro. In most cases, these employees took Cipro as a preventative measure, and never actually had inhalation anthrax. In all, 1,132 people who either worked for American Media, were related to employees, had been in the building in the previous 60 days or worked at post offices that processed the company’s mail took antibiotics. Most – 86 percent – were put on Cipro, two 500 mg doses per day, and the recommended duration was 60 days.

A Centers for Disease Control study released in the fall of 2002 revealed that of 5,343 people studied who took the anthrax antibiotics in 2001 – not only in Florida but in New York, New Jersey and Washington, D.C. – 57 percent reported adverse side effects while they were taking the drugs. Almost all were minor, with the most common being nausea, vomiting, headaches and dizziness, but some also suffered tendinitis, fainting spells and seizures. Sixteen percent of those people were sick enough to require medical attention.