From the Guidelines
Dicloxacillin is effective against methicillin-susceptible Staphylococcus aureus (MSSA) and Streptococcus species, making it a suitable treatment option for skin and soft-tissue infections (SSTIs) such as impetigo and ecthyma.
Key Points
- The recommended dosage of dicloxacillin for adults is 250-500 mg four times a day orally [ 1 ], while for children it is 12-25 mg/kg/day in four divided doses orally [ 1 ].
- Dicloxacillin is an oral agent of choice for methicillin-susceptible strains of S. aureus [ 1 ].
- The duration of therapy with dicloxacillin is typically 7 days, depending on the clinical response [ 1 ].
- When methicillin-resistant S. aureus (MRSA) is suspected or confirmed, alternative treatments such as doxycycline, clindamycin, or sulfamethoxazole-trimethoprim (SMX-TMP) are recommended [ 1 ].
Important Considerations
- Dicloxacillin is not effective against MRSA, and alternative treatments should be used when MRSA is suspected or confirmed [ 1 ].
- The choice of antibiotic therapy should be based on the severity and depth of the wound, as well as the time since the bite or injury [ 1 ].
From the FDA Drug Label
When dicloxacillin sodium capsules are prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed Dicloxacillin may reduce the anticoagulant response to dicumarol and warfarin The mechanism of this possible interaction is unclear, but may be due to hepatic enzyme induction.
The effect of Dicloxacillin is to treat bacterial infections.
- It can make patients feel better early in the course of therapy.
- It may interact with other medications, such as anticoagulants, by reducing their effectiveness.
- The exact mechanism of some interactions is unclear. 2 2
From the Research
Effect of Dicloxacillin
- Dicloxacillin is effective in treating pyo-inflammatory diseases, such as pneumonia, pyothorax, pulmonary abscess, osteomyelitis, burn disease, infections of the skin and soft tissues, and others, caused by multiresistant staphylococci and other organisms sensitive to the antibiotic 3.
- The drug is effective both orally and parenterally, with satisfactory results observed in more than 80% of patients (children and adults) 3.
- Dicloxacillin has antimicrobial activity against a wide variety of gram-positive bacteria, including Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumonia, Streptococcus epidermidis, Streptococcus viridans, Streptococcus agalactiae, and Neisseria meningitidis 4.
- The therapeutic efficacy of dicloxacillin or flucloxacillin, 1-2 g orally with probenecid twice daily, was evaluated in staphylococcal infections, with excellent results obtained in patients with relapsing chronic osteomyelitis and postoperative infections 5.
Pharmacokinetics and Safety
- The maximum plasma drug concentration (Cmax) and the corresponding values for the area under the concentration-time curve from 0 to 10 hours (AUC0-10 h) increased in a dose-proportional manner after a single oral dose of 0.25-2.0 g dicloxacillin sodium 4.
- The mean elimination half-life (t1/2) was in the range of 1.38-1.71 hours, and dicloxacillin was excreted in its unchanged form via the kidney, with no tendency of accumulation 4.
- No serious adverse events were reported, and adverse events were generally mild, with dicloxacillin being safe and well tolerated in healthy volunteers 4.
Antibacterial Activity
- Dicloxacillin showed poor antibacterial activity against Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae, with resistance observed in 7.5% of coagulase-negative Staphylococcus (CNS) isolates and 9.2% of other Streptococcus isolates 6.
- However, all dosing regimens against methicillin-sensitive Staphylococcus aureus (MSSA) achieved a cumulative fraction of response (CFR) ≥ 90% 6.
- The combination of dicloxacillin and fusidic acid had a lower intracellular killing effect on Staphylococcus aureus compared to dicloxacillin alone 7.