indication

For the treatment of bacterial conjunctivitis caused by susceptible strains of the following organisms: Corynebacterium species, Staphylococus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus (Groups C/F/G), Viridans group streptococci, Acinetobacter lwoffii, Haemophilus influenzae, Serratia marcescens.

pharmacology

Levofloxacin, a fluoroquinolone antiinfective, is the optically active L-isomer of ofloxacin. Levofloxacin is used to treat bacterial conjunctivitis, sinusitis, chronic bronchitis, community-acquired pneumonia and pneumonia caused by penicillin-resistant strains of Streptococcus pneumoniae, skin and skin structure infections, complicated urinary tract infections and acute pyelonephritis.

mechanism of action

Levofloxacin inhibits bacterial type II topoisomerases, topoisomerase IV and DNA gyrase. Levofloxacin, like other fluoroquinolones, inhibits the A subunits of DNA gyrase, two subunits encoded by the gyrA gene. This results in strand breakage on a bacterial chromosome, supercoiling, and resealing; DNA replication and transcription is inhibited.

toxicity

Side effects include disorientation, dizziness, drowsiness, hot and cold flashes, nausea, slurring of speech, swelling and numbness in the face

biotransformation

Mainly excreted as unchanged drug (87%); undergoes limited metabolism in humans.

absorption

Absorption of ofloxacin after single or multiple doses of 200 to 400 mg is predictable, and the amount of drug absorbed increases proportionately with the dose.

half life

6-8 hours

route of elimination

Mainly excreted as unchanged drug in the urine.

drug interactions

Acenocoumarol: The quinolone antibiotic, levofloxacin, may increase the anticoagulant effect of acenocoumarol.

Aluminium: Formation of non-absorbable complexes

Amiodarone: Increased risk of cardiotoxicity and arrhythmias

Anisindione: The quinolone antibiotic, levofloxacin, may increase the anticoagulant effect of anisindione.

Artemether: Additive QTc-prolongation may occur. Concomitant therapy should be avoided.

Bepridil: Increased risk of cardiotoxicity and arrhythmias

Bretylium: Increased risk of cardiotoxicity and arrhythmias

Calcium: Formation of non-absorbable complexes

Calcium Acetate: Calcium salts such as calcium acetate may decrease the absorption of quinolone antibiotics such as levofloxacin. Of concern only with oral administration of both agents. Interactions can be minimized by administering oral quinolone at least 2 hours before, or 6 hours after, the dose of an oral calcium supplement. Monitor for decreased therapeutic effects of oral quinolones if administered with oral calcium supplements.

Chlorpromazine: Increased risk of cardiotoxicity and arrhythmias

Dicumarol: The quinolone antibiotic, levofloxacin, may increase the anticoagulant effect of dicumarol.

Dihydroquinidine barbiturate: Increased risk of cardiotoxicity and arrhythmias

Disopyramide: Increased risk of cardiotoxicity and arrhythmias

Erythromycin: Increased risk of cardiotoxicity and arrhythmias

Fluphenazine: Increased risk of cardiotoxicity and arrhythmias

Iron: Formation of non-absorbable complexes

Iron Dextran: Formation of non-absorbable complexes

Josamycin: Increased risk of cardiotoxicity and arrhythmias

Lumefantrine: Additive QTc-prolongation may occur. Concomitant therapy should be avoided.

Magnesium: Formation of non-absorbable complexes

Magnesium oxide: Formation of non-absorbable complexes

Mesoridazine: Increased risk of cardiotoxicity and arrhythmias

Methotrimeprazine: Increased risk of cardiotoxicity and arrhythmias

Perphenazine: Increased risk of cardiotoxicity and arrhythmias

Procainamide: Levofloxacin may increase the effect of procainamide.

Prochlorperazine: Increased risk of cardiotoxicity and arrhythmias

Promazine: Increased risk of cardiotoxicity and arrhythmias

Promethazine: Increased risk of cardiotoxicity and arrhythmias

Propiomazine: Increased risk of cardiotoxicity and arrhythmias

Quinidine: Increased risk of cardiotoxicity and arrhythmias

Quinidine barbiturate: Increased risk of cardiotoxicity and arrhythmias

Quinupristin: This combination presents an increased risk of toxicity

Sotalol: Increased risk of cardiotoxicity and arrhythmias

Sucralfate: Formation of non-absorbable complexes

Tacrolimus: Additive QTc-prolongation may occur increasing the risk of serious ventricular arrhythmias. Concomitant therapy should be used with caution.

Thiethylperazine: Increased risk of cardiotoxicity and arrhythmias

Thioridazine: Increased risk of cardiotoxicity and arrhythmias

Thiothixene: May cause additive QTc-prolonging effects. Increased risk of ventricular arrhythmias. Consider alternate therapy. Thorough risk:benefit assessment is required prior to co-administration.

Toremifene: Additive QTc-prolongation may occur, increasing the risk of serious ventricular arrhythmias. Consider alternate therapy. A thorough risk:benefit assessment is required prior to co-administration.

Trifluoperazine: Increased risk of cardiotoxicity and arrhythmias

Triflupromazine: Increased risk of cardiotoxicity and arrhythmias

Trimipramine: Additive QTc-prolongation may occur, increasing the risk of serious ventricular arrhythmias. Concomitant therapy should be used with caution.

Voriconazole: Additive QTc prolongation may occur. Consider alternate therapy or monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).

Vorinostat: Additive QTc prolongation may occur. Consider alternate therapy or monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).

Warfarin: The quinolone antibiotic, levofloxacin, may increase the anticoagulant effect of warfarin.

Zinc: Formation of non-absorbable complexes

Ziprasidone: Additive QTc-prolonging effects may increase the risk of severe arrhythmias. Concomitant therapy is contraindicated.

Zuclopenthixol: Additive QTc prolongation may occur. Consider alternate therapy or use caution and monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).