Category: Antibiotics

Gemifloxacin Mesylate for Resistant Community-Acquired Pneumonia

Gemifloxacin Mesylate

The FDA has approved gemifloxacin mesylate (Factive®, GeneSoft) to treat mild-to-moderate community-acquired pneumonia (CAP) caused by multidrug-resistant Streptococcus pneumoniae. Fac-tive®, an orally administered, broad-spectrum generic fluoroquinolone, is the first antibiotic specifically indicated for CAP caused by this resistant organism.

In April 2003, Factive® was approved in the U.S. to treat mild-to-moderate CAP caused by other pathogens and for acute bacterial exacerbations of chronic bronchitis.

Pneumonia is the primary cause of death from infections. More than 25% of S. pneumoniae isolates in the U.S. are multi-drug-resistant, defined as strains that are resistant to two or more of the following antibiotics: penicillin, second-generation cephalosporins, macrolides, tetracyclines, and canadian trimethoprim/sulfamethoxazole.

Which Drug for Pneumonia

It’s about a hundred times more expensive, but it may be the better choice anyway. In phase III studies for the treatment of gram-positive hospital-acquired (nosocomial) pneumonia, Linezolid (Zyvox canadian, Pharmacia & Upjohn) was superior to vancomycin (Vancocin® HCl, Eli Lilly), report researchers from Methodist University Hospital. Their findings were presented at an American Thoracic Society meeting in Seattle in May 2003.

Linezolid was particularly efficacious in treating methicillin-resistant Staphylococcus aureus (MRSA) pneumonia, and patients receiving linezolid were twice as likely to survive as patients who received vancomycin. The researchers explained that vancomycin is associated with renal toxicity, and patients at risk for renal problems might therefore be receiving underdoses. Linezolid is not associated with renal toxicity, and it seems to offer greater lung penetration.

Linezolid generic, which was approved in 2000, is the first FDA-approved oxazolidinone, a new class of antibiotics.

Switching Antibiotics Can Save Lives

Cutting back on third-generation cephalosporins might reduce the number of infection-related deaths in critically ill patients, according to a study at a tertiary-care hospital in Beijing, China.

In phase 1, patients with confirmed or suspected gram-negative bacterial infections were treated primarily with third-generation cephalosporins, such as ceftazidim (Fortaz®, GlaxoSmithKline) and ceftriaxone sodium (Rocephalin®, Roche). In phase 2, they received other antibiotics, such as fourth-generation cephalosporins and carbapenems.
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Phase 2 clinical outcomes were better than those in phase 1. Patients’ stays in the intensive-care unit were shorter (17.6 days versus 29.3 days), and they were more likely to survive (16 of 83 [19.3%] vs. 29 of 80 [36.3%]). Mortality rates dropped significantly in patients with pseudomonal and lower respiratory infections.

Antibiotics after Acute Myocardial Infarction

Giving antibiotics to help prevent inflammation in patients with coronary disease is an attractive idea to clinical researchers for a number of reasons. Many studies have focused on whether antibiotics can help change the course of coronary artery syndromes. Results have been mixed, with smaller studies tending to show benefits but larger trials showing no advantages.

One large study, Antibiotic Therapy after an Acute Myocardial Infarction (ANTIBIO), monitored 868 patients for 12 months. Patients who were given roxithromycin (e.g., Generic Rulid®, Aventis) 300 mg/day for six weeks fared no better and no worse than patients given placebo. Of 431 patients in the drug group, 28 died (6.5%); of 437 placebo patients, 26 died (6%).

The ANTIBIO researchers noted that the type of macrolide ( generic roxithromycin or azithromycin drug [Zithromax tablet, Pfizer]), the type coronary artery disease (unstable or stable), the duration of therapy, and whether or not patients had C. pneumo-niae infection did not seem to have a major impact on the effect of antibiotic treatment. Because smaller trials have been more likely to show benefits, the researchers suggest that the effect of antibiotics, when added to standard therapy, might be very small and perhaps limited to certain patient subgroups, such as patients with high antibody titers. They add that their findings challenge the hypothesis that C. pneumoniae plays a major role in the pathogenesis of arteriosclerosis.

After the Anthrax Scare: Is Ciproflaxacin Still Effective

Is the antibiotic that was administered as a protective measure in the U.S. during the anthrax scare in 2001 becoming less effective against other bacteria because of overuse?

In 1994, ciprofloxacin (Cipro canadian, Bayer) was found to be efficacious against 86% of bacterial samples analyzed; by the year 2000, the rate had declined to 76%.

In a multicenter study, researchers examined data on infections in hospitalized patients in 43 states, including Washington, DC, from 1994 to 2000. Ailments included respiratory and urinary infections caused by various bacteria.

Many organisms had grown resistant to fluoroquinolones, a class of antibiotics that includes ciprofloxacin. The anthrax bacterium was not studied, and the researchers noted that their findings did not mean that the drug was becoming less effective against anthrax, which often affects animals but rarely humans.

Bacteria that became increasingly resistant during the study were all com­mon causes of infections and included Escherichia coli.

When a drug is used repeatedly against the same organism, it has the potential to mutate into drug-resistant forms. The greater resistance came at a time when physicians were increasingly prescribing generic ciprofloxacin and similar drugs for common ailments such as respiratory infections caused by viruses, which are unaffected by antibiotics, the researchers noted. They urged more judicious use of the floroquinolones to limit the downward trend.

Antibiotic Therapy and Tremors

Antibiotic Therapy

Patients receiving high-dose drug trimethoprim sulfamethoxazole (TMP-SMX, Generic Bactrim®, Women First; Septra®, Monarch) appear to be at higher risk for abnormal muscle contractions such as myoclonus and asterixis. In fact, these side effects might not be as rare as once thought.

A 63-year-old woman with a history of non-Hodgkin’s lymphoma, hypertension, hypercholesterolemia, and transient ischemic attack had recently been in remission for acute myelogenous leukemia. Admitted to the hospital with a Nocardia asteroides infection, she began a regimen of trimethoprim 20 mg/kg per day and canadian sulfamethoxazole 100 mg/kg per day, given intravenously in two doses, along with 2 g of ceftriaxone sodium (Rocephin®, Roche), given twice daily.

Her fever abated, but she began to experience progressively worsening involuntary movements involving her head and her extremities. Neurological examination revealed diffuse, multifocal myo-clonus and bilateral asterixis but no other abnormalities. The TMP-SMX therapy was stopped, and the involuntary movements decreased markedly the next day. By the fourth day, they disappeared.

The physicians knew of only one report describing tremors in an immuno-competent patient.

The complication of tremors is dose-related, not immunological. The physicians suggest that the “rare” effect might actually be underdiagnosed, and they advise stopping TMP-SMX treatment before ordering a costly neurological evaluation.

Quinolones and Tendon Rupture

Since their introduction in the 1980s, quinolones have been associated with tendon disorders. So it isn’t farfetched to speculate that the rising number of case reports of Achilles’ tendon ruptures and other similar problems might be linked to the increased use of quinolones. That’s the basis of a study analyzing 1,367 cases reported in the United Kingdom between 1988 and 1998. The researchers defined cases as those in which the patient had a first-time recorded …