Felon Medication

Updated: Mar 11, 2021
  • Author: Brandon Stein, MD; Chief Editor: Steven C Dronen, MD, FAAEM  more...
  • Print

Medication Summary

The goals of pharmacotherapy are to treat infections and prevent further complications.



Class Summary

Empirical coverage for S aureus and streptococcal organisms should be provided. While a first-generation cephalosporin or antistaphylococcal penicillin has traditionally been recommended, the rapid emergence of community-acquired methicillin-resistant S aureus (CA-MRSA) requires treatment with drugs more likely to be effective against this agent. Trimethoprim/sulfamethoxazole or clindamycin should be added for this coverage. Coverage for E corrodens may be indicated for immunosuppressed patients and bite wounds. Tailor antibiotics to cultures and sensitivities. Continue antibiotics for 7-10 days.

Dicloxacillin (Dycill, Dynapen)

Bactericidal antibiotic that inhibits cell wall synthesis; DOC to treat infections caused by penicillinase-producing staphylococci. May be used to initiate therapy when staphylococcal infection is suspected.

Cephalexin (Keflex, Biocef)

Another alternative antibiotic. First-generation cephalosporin that inhibits bacterial replication by inhibiting bacterial cell wall synthesis. Bactericidal and effective against rapidly growing organisms forming cell walls.


Inhibits bacterial growth by inhibiting synthesis of dihydrofolic acid.


Semisynthetic antibiotic produced by 7(S)-chloro-substitution of 7(R)-hydroxyl group of parent compound lincomycin. Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Widely distributes in the body without penetration of CNS. Protein bound and excreted by the liver and kidneys.

Amoxicillin and clavulanate

Amoxicillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. Addition of clavulanate inhibits beta-lactamase producing bacteria.

Good alternative antibiotic for patients allergic or intolerant to the macrolide class. Usually is well tolerated and provides good coverage to most infectious agents. Not effective against Mycoplasma and Legionella species. The half-life of oral dosage form is 1-1.3 h. Has good tissue penetration but does not enter cerebrospinal fluid.

For children >3 months, base dosing protocol on amoxicillin content. Due to different amoxicillin/clavulanic acid ratios in 250-mg tab (250/125) vs 250 mg chewable-tab (250/62.5), do not use 250-mg tab until child weighs >40 kg.

Nafcillin (Unipen)

Indicated for severe infections.

Treats infections caused by penicillinase-producing staphylococci. Used to initiate therapy in any patients with possible penicillin G-resistant staphylococcal infection. Do not use for treatment of penicillin G-susceptible staphylococcal organisms.

Use parenteral therapy initially in severe infections. Severe infections may require very high doses.

Change to oral therapy as condition improves.

Because of occasional occurrence of thrombophlebitis associated with the parenteral route, particularly in elderly patients, administer parenterally only for a short term (24-48 h) and change to oral route if clinically possible.


Broad-spectrum, synthetically derived bacteriostatic antibiotic in the tetracycline class. Almost completely absorbed, concentrates in bile, and is excreted in urine and feces as a biologically active metabolite in high concentrations.

Inhibits protein synthesis and, thus, bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria. May block dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest.

Provides good coverage against Spirochetes, many gram-negative organisms, anaerobic organisms, atypical bacteria, and many gram-positive organisms.