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Neomycyna - Skuteczny Lek na Pryszcze?
Przeciwwskazania do stosowania neomycyny
Neomycyna nie może być stosowana przez każdą osobę. W pierwszej kolejności jej podaż jest wykluczona w przypadku osób wykazujących nadwrażliwość na antybiotyki aminoglikozydowe lub inne substancje obecne w leku.
Ponadtonie powinna być przyjmowana przez kobiety ciężarne oraz karmiące piersią ze względu na to, że substancja ta wchłania się przez łożysko i mleko kobiece, a może być szkodliwa dla płodu.
Innymi przeciwwskazaniami do stosowania neomycyny są takie sytuacje jak:
- schorzenia nerek,
- choroby nerwowo-mięśniowe,
- parkinsonizm.
Należy zachować szczególną ostrożność z aplikowaniem antybiotyku miejscowo w przypadku występowania owrzodzeń żylakowatych, sączących się ran i innych zmian chorobowych na skórze. Ponadto należy przemyśleć stosowanie i dawkowanie neomycyny u dzieci (w szczególności u noworodków i wcześniaków), osób starszych, a także u pacjentów borykających się z zaburzeniami pracy nerek.
Administration
Neomycin can be administered through various routes, yet its GI absorption is limited, which is similar to most aminoglycosides.[1]
Although oral administration primarily targets the GI tract, alternatively, topical formulations of neomycin are also accessible for localized use.
Adult Dosage
Hepatic coma
In treating hepatic coma, the recommended dosage for neomycin is 1000 to 3000 mg administered orally every 6 hours, and this regimen can be continued for up to 6 days to manage hepatic encephalopathy. According to The American Association for the Study of Liver Diseases (AASLD) guidelines, rifaximin and lactulose is the preferred treatment regimen. However, neomycin is explicitly used for cases of overt hepatic encephalopathy.[2]
Surgical (perioperative) prophylaxis
The recommended dosage of oral neomycin for surgical prophylaxis is 1000 mg, administered in combination with erythromycin or metronidazole base at 1 pm, 2 pm, and 11 pm on the day before the surgery.[3] Certain resources may depict administration times that vary by an hour from these guidelines.
Specific Patient Populations
Hepatic impairment: The manufacturer's labeling does not provide specific dosage adjustments of neomycin for individuals with hepatic impairment.
Renal impairment: The manufacturer's labeling does not include explicit dosage adjustments of neomycin for individuals with renal impairment. However, it is crucial to exercise caution with patients experiencing renal insufficiency, as inadequate dosage regulation can lead to elevated blood levels and potential toxicity. If renal insufficiency develops during treatment, healthcare providers should consider lowering the dosage or discontinuing the administration of antibiotics.
Pregnancy considerations: As an aminoglycoside, neomycin can cross the placenta. The administration of this drug during pregnancy carries the potential for teratogenic effects. Therefore, after conducting a thorough risk-benefit evaluation, neomycin should only be administered to pregnant individuals when necessary. Neomycin is classified as an FDA pregnancy Category C medication.[11]
Biosynthetic pathway [ edit ]
Neomycin was first isolated from the Streptomyces fradiae and Streptomyces albogriseus in 1949 (NBRC 12773). [18] Neomycin is a mixture of neomycin B (framycetin), and its epimer neomycin C, the latter component accounting for some 5–15% of the mixture. It is a basic compound that is most active with an alkaline reaction. [5] It is also thermostable and soluble in water (while insoluble in organic solvents). [5] Neomycin has good activity against Gram-positive and Gram-negative bacteria, but is ototoxic. Its use is thus restricted to the oral treatment of intestinal infections. [19]
Neomycin B is composed of four linked moieties: D-neosamine, 2-deoxystreptamine (2-DOS), D-ribose, and L-neosamine. [ citation needed ]
Next is the attachment of the D-ribose via ribosylation of neamine, using 5-phosphoribosyl-1-diphosphate (PRPP) as the ribosyl donor (BtrL, BtrP), [22] glycosyltransferase (potential homologues RibF, LivF, Parf) gene (Neo15). [23]
Neosamine B (L-neosamine B) is most likely biosynthesized in the same manner as the neosamine C (D-niosamine) in neamine biosynthesis, but with an additional epimerization step required to account for the presence of the epimeric neosamine B in neomycin B. [24]
Neomycin B and C are 23-carbon molecules with a four-ring structure. Three of the rings are six-membered, and one is five-membered. [25] Neomycin B and Neomycin C are stereoisomers of each other and differ by only one stereocenter one giving the R conformation and the other giving the S conformation. [26] Neomycin C can undergo enzymatic synthesis from ribostamycin. [27]