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ACUTE OTITIS MEDIA
Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the most common causes of acute otitis media (AOM). Strep. pneumoniae, the most frequent cause, is also the least likely to resolve without treatment. The emergence of drug-resistant Strep. pneumoniae (DRSP) has increased the number of treatment failures, and complicated the selection of empiric therapy.
According to a recent consensus of experts, amoxicillin remains the drug of choice for the treatment of uncomplicated AOM, regardless of the presence of DRSP in the community. Standard doses of amoxicillin (40-45 mg/kg/day) are recommended for patients at a low risk of infection with DRSP. Patients at high risk of DRSP (i.e., antimicrobial exposure within the previous month, age <2 years and/or attendance at daycare) should receive higher doses of amoxicillin (80-90 mg/kg/day for five to seven days).
If amoxicillin fails to improve symptoms (e.g., ear pain, fever, tympanic membrane redness) within three days, amoxicillin-clavulanate (80-90 mg/kg/ day amoxicillin, and approximately 10 mg/kg/ day clavulanate for 10 days), cefuroxime axetil, or a single dose (50 mg/kg) of intramuscular (IM) ceftriaxone should be used. IM ceftriaxone (three once-daily injections), oral clindamycin (in culture-confirmed Strep. pneumoniae only) or tympanocentesis should be used if the patient received an antibiotic within the previous month. Trimethoprim/ sulfamethoxazole and macrolide antibiotics are no longer recommended as second-line therapy.1
ONCE-DAILY AMOXICILLIN FOR
A recent study of 152 children suggests that once-daily amoxicillin is an effective therapy for the treatment of group A beta-hemolytic streptococcal pharyngitis. The study compared amoxicillin 750 mg once daily to penicillin V 250 mg three times daily. Both drugs were given orally for 10 days. There was no significant difference in clinical response between the two treatments. Bacteriological treatment failures (determined by follow-up throat cultures) occurred in five per cent of the children treated with amoxicillin, and 11 per cent treated with penicillin.
If these results are confirmed by other studies, the authors suggest that once-daily amoxicillin could become an alternative regimen for the treatment of streptococcal pharyngitis. Once-daily therapy would be more convenient for patients, and might result in improved patient compliance.2
USEFUL IN RHEUMATOID ARTHRITIS?
The role of minocycline in the treatment of rheumatoid arthritis (RA) continues to be debated. Investigators have postulated that it may be beneficial, based on the hypothesis that RA is caused by a persistent infectious process involving Mycoplasma. It has also been speculated that tetracyclines have anti-inflammatory effects, and inhibit the enzymes involved in joint destruction. Overall, clinical studies with minocycline (100 mg twice daily) have found a 54 per cent response rate in RA, accompanied by improvements in laboratory tests; however, the placebo response in these trials was also high (39%). The drug seems to be more effective when used early in the disease, while only modest improvements are seen in the later stages of RA.3
WHAT’S ITS ROLE IN THERAPY?
Compared to other quinolones, trovafloxacin has enhanced activity against gram-positive and anaerobic organisms. It may be a useful monotherapy for the treatment of polymicrobial infections (e.g., skin/soft tissue infections, intra-abdominal infections). However, its activity against gram-negative organisms is generally lower than that of ciprofloxacin. Studies comparing trovafloxacin to other quinolones are lacking, and are needed to define its role in therapy.4
LU-ANN MURDOCH,B.Sc.Phm. is consulting clinical editor of Pharmacy Practice.
1. Dowell SF, Butler JC, Giebink GS, et al. Acute otitis media: management and surveillance in an era of pneumococcal resistance–a report from the Drug-resistant Streptococcus pneumoniae Therapeutic Working Group. Pediatr Infect Dis J 1999;18:1-9.
2. Feder HM Jr, Gerber MA, Randolph MF, et al. Once-daily therapy for streptococcal pharyngitis with amoxicillin. Pediatrics 1999;103:47-51.
3. Klutman NE. Minocycline for rheumatoid arthritis. Hosp Pharm 1999;34:88-99.
4. Alghasham AA, Nahata MC. Trovafloxacin: a new fluoroquinolone. Ann Pharmacother 1999;33:48-60.