Local treatment of external bacterial eye infections caused by microorganisms sensitive to levofloxacin.
Levoximed drops Storage
active substance: levofloxacin;
1 ml of solution contains levofloxacin (as hemihydrate) 5 mg;
Excipients: sodium chloride, benzalkonium chloride, sodium hydroxide solution or concentrated hydrochloric acid, purified water.
Levoximed drops Dosage form
Eye drops, solution.
Basic physical and chemical properties: transparent light yellow or greenish-yellow solution.
Levoximed drops Pharmacotherapeutic group
Means used in ophthalmology. Antimicrobials. Fluoroquinolones. Levofloxacin. ATC code S01A E05.
Levoximed drops Pharmacological properties
Levofloxacin is the L-isomer of the racemic drug ofloxacin. The L-isomer of ofloxacin has an antibacterial effect.
Mechanism of action
Levofloxacin is an antibacterial agent of the fluoroquinolone group, which inhibits the activity of bacterial topoisomerases of type II – DNA gyrase and topoisomerase IV. The action of levofloxacin in gram-negative bacteria is directed mainly on DNA gyrase, and in gram-positive bacteria on – topoisomerase IV.
Mechanisms of resistance
There are two main mechanisms of bacterial resistance to levofloxacin: a decrease in its concentration within the bacterial cell and changes in the set of enzymes against which the action of levofloxacin is directed. Such changes are due to mutations in chromosomal genes encoding DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE; grlA and grlB in Staphylococcus aureus). Causes of resistance due to a decrease in the concentration of levofloxacin inside the bacterial cell are changes in the porins of the outer membrane (OmpF), which reduces the possibility of penetration of fluoroquinolones into gram-negative bacteria, or pumps that promote the outflow of substances. Outflow resistance has been described in pneumococci (PmrA), staphylococci (NorA), anaerobic and gram-negative bacteria. Resistance to quinolones through blood plasma (determined by the qnr gene) has been reported in Klebsiella pneumoniae and E. coli.
Cross-resistance between fluoroquinolones may occur. Single mutations do not result in clinical resistance, but multiple mutations usually do cause clinical resistance to all drugs in the fluoroquinolone class. Changes in the porins of the outer membrane and the outflow system can have a broad substrate specificity, be directed against several classes of antibacterial agents and lead to multiple resistance.
Limit values of MIC (minimum inhibitory concentration), which separate sensitive and moderately resistant organisms from resistant according to the limit value EUCAST (European Committee on Antimicrobial Susceptibility Testing – European Committee for Antimicrobial Susceptibility Testing), are as follows:
Pseudomonas spp., Staphylococcus spp., Streptococcus A, B, C, G:
sensitive ≤ 1 mg / l, resistant> 2 mg / l;
Streptococcus pneumoniae: sensitive ≤ 2 mg / l, resistant> 2 mg / l;
Haemophilus influenzae, Moraxella catarrhalis: sensitive ≤ 1 mg / l, resistant> 1 mg / l.
Other pathogenic microorganisms: sensitive ≤ 1 mg / l, resistant> 2 mg / l.
Spectrum of antibacterial action
The prevalence of acquired resistance in individual species may vary in different geographical locations and over time, so it is desirable to have local information on resistance, especially in the treatment of severe infections. Therefore, the information provided provides only approximate guidelines and recommendations for possible susceptibility of microorganisms to levofloxacin. If the prevalence of resistance in the field is such that the use of the drug against at least some types of infections is questionable, if necessary, consult a specialist. The table below lists only the types of bacteria that usually cause external infectious eye diseases, such as conjunctivitis.