indication

Used to treat infections caused by penicillinase-producing staphylococci which have demonstrated susceptibility to the drug.

pharmacology

Dicloxacillin is a beta-lactamase resistant penicillin similar to oxacillin. Dicloxacillin has in vitro activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of dicloxacillin results from the inhibition of cell wall synthesis and is mediated through dicloxacillin binding to penicillin binding proteins (PBPs). Dicloxacillin is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases.

mechanism of action

Dicloxacillin exerts a bactericidal action against penicillin-susceptible microorganisms during the state of active multiplication. All penicillins inhibit the biosynthesis of the bacterial cell wall. By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, dicloxacillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that dicloxacillin interferes with an autolysin inhibitor.

toxicity

Oral LD₅₀ in rat is 3579 mg/kg. Symptoms of overexposure include irritation, rash, labored breathing, hives, itching, wheezing, nausea, chills, and fever.

absorption

Absorption of the isoxazolyl penicillins after oral administration is rapid but incomplete: peak blood levels are achieved in 1-1.5 hours. Oral absorption of cloxacillin, dicloxacillin, oxacillin and nafcillin is delayed when the drugs are administered after meals.

half life

The elimination half-life for dicloxacillin is about 0.7 hour.

route of elimination

Dicloxacillin sodium is rapidly excreted as unchanged drug in the urine by glomerular filtration and active tubular secretion.

drug interactions

Acenocoumarol: Dicloxacillin may decrease the anticoagulant effect of acenocoumarol.

Anisindione: Dicloxacillin may decrease the anticoagulant effect of anisindione.

Demeclocycline: Possible antagonism of action

Dicumarol: Dicloxacillin may decrease the anticoagulant effect of dicumarol.

Doxycycline: Possible antagonism of action

Ethinyl Estradiol: This anti-infectious agent could decrease the effect of the oral contraceptive

Mestranol: This anti-infectious agent could decrease the effect of the oral contraceptive

Methacycline: Possible antagonism of action

Methotrexate: The penicillin increases the effect and toxicity of methotrexate

Minocycline: Possible antagonism of action

Oxytetracycline: Possible antagonism of action

Rolitetracycline: Possible antagonism of action

Tetracycline: Possible antagonism of action

Warfarin: Dicloxacillin may decrease the anticoagulant effect of warfarin.