Osteomyelitis is an infection of the bone, most often
caused by bacteria such as Staphylococcus aureus
, although other
microbes, including mycobacteria and fungi, are sometimes responsible.
Osteomyelitis can be classified as acute or chronic. Unlike the acute form, which results from spread of
bacteria through the blood, chronic osteomyelitis develops from fractures, open
wounds, soft-tissue infections, and orthopedic implants.
Individuals with certain conditions or diseases that
weaken the immune system such as diabetes, HIV/AIDS, sickle cell anemia and
alcoholism are more prone to osteomyelitis.
Symptoms of osteomyelitis include redness, warmth, malaise,
swelling and pain in the affected area, high fever, nausea and bone necrosis.
Chronic osteomyelitis is diagnosed based on laboratory tests like erythrocyte
sedimentation rate and C-reactive protein, imaging studies like x-ray and MRI,
and microbiological examination that includes antibiotic sensitivity of
Current treatment consists of surgery
plus a prolonged antibiotic therapy of 4 to 6 weeks. Surgery is
necessary to remove the infected and devitalized bone and tissues. Up until
fairly recently, administering oral antibiotics during this time period was
rarely considered as a viable option. Oral therapy is now growing in popularity
as evidenced by the fact that there are numerous studies conducted with oral
agents. These studies have shown that oral antibiotics work equally well as
parenteral agents to achieve adequate levels in bone.
Several oral antimicrobial agents have undergone
evaluation for the treatment of acute and chronic osteomyelitis. They include fluoroquinolones such as ciprofloxacin, ofloxacin,
levofloxacin, moxifloxacin; rifampin; linezolid; sulfamethoxazole-trimethoprim
(SMX-TMP); aminopenicillins such as ampicillin and amoxicillin; and
beta-lactamase inhibitors such as sulbactam and clavulanic acid.
In a prospective, randomized study, ciprofloxacin
was compared with a standard parenteral regimen (IV ceftazidime) for
osteomyelitis. The cure rate was 77% in the ciprofloxacin group, versus 79% in
the IV-treatment group.
In another study in osteomyelitis, the
administration of parenteral ciprofloxacin followed by oral therapy was
compared with IV ceftazidime. Two of three patients were cured with
ciprofloxacin therapy, as were all three patients receiving ceftazidime.
Rifampin was evaluated in combination with IV
nafcillin. One group received the combination whereas the other group received
parenteral nafcillin only. Nearly 80% cure rate was reported in the
combined-treatment group, whereas the cure rate was 50% in the nafcillin-only
In yet another study, Group A
patients received IV cloxacillin followed by oral cloxacillin. Group B patients
received a rifampin-cotrimoxazole combination. The overall cure rate in both
groups after 10 years was nearly 90%, suggesting that oral SMX-TMP was an
effective treatment option for chronic osteomyelitis.
these studies indicate that oral therapy has been found to be nearly equivalent
to parenteral therapy in chronic osteomyelitis. Oral and parenteral
therapies have been shown to achieve similar cure rates; however, the
advantages of oral therapy are that it avoids risks associated with intravenous
catheters, provides excellent bone concentration and activity against targeted
organisms, has reduced incidence of resistance, has fewer adverse effects even
at high doses and is generally less expensive, making it a reasonable choice
for treatment of osteomyelitis caused by susceptible organisms.
: Oral Treatment Options for Chronic
Osteomyelitis; Seher Khan et al; US Pharm.