Neomycin¿¡ ´ëÇÑ Mechanism_Of_Action Á¤º¸ Aminoglycosides like neomycin "irreversibly" bind to specific 30S-subunit proteins and 16S rRNA. Specifically neomycin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes. Prednisolone¿¡ ´ëÇÑ Mechanism_Of_Action Á¤º¸ Glucocorticoids such as Prednisolone can inhibit leukocyte infiltration at the site of inflammation, interfere with mediators of inflammatory response, and suppress humoral immune responses. The antiinflammatory actions of glucocorticoids are thought to involve phospholipase A2 inhibitory proteins, lipocortins, which control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes. Prednisolone reduces inflammatory reaction by limiting the capillary dilatation and permeability of the vascular structures. These compounds restrict the accumulation of polymorphonuclear leukocytes and macrophages and reduce the release of vasoactive kinins. Recent research suggests that corticosteroids may inhibit the release of arachidonic acid from phospholipids, thereby reducing the formation of prostaglandins. Prednisolone is a glucocorticoid receptor agonist. On binding, the corticoreceptor-ligand complex translocates itself into the cell nucleus, where it binds to many glucocorticoid response elements (GRE) in the promoter region of the target genes. The DNA bound receptor then interacts with basic transcription factors, causing an increase or decrease in expression of specific target genes, including suppression of IL2 (interleukin 2) expression.
Pharmacology
Neomycin¿¡ ´ëÇÑ Pharmacology Á¤º¸ Neomycin is an aminoglycoside antibiotic. Aminoglycosides work by binding to the bacterial 30S ribosomal subunit, causing misreading of t-RNA, leaving the bacterium unable to synthesize proteins vital to its growth. Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter. In addition, some mycobacteria, including the bacteria that cause tuberculosis, are susceptible to aminoglycosides. Infections caused by Gram-positive bacteria can also be treated with aminoglycosides, but other types of antibiotics are more potent and less damaging to the host. In the past the aminoglycosides have been used in conjunction with penicillin-related antibiotics in streptococcal infections for their synergistic effects, particularly in endocarditis. Aminoglycosides are mostly ineffective against anaerobic bacteria, fungi and viruses. Prednisolone¿¡ ´ëÇÑ Pharmacology Á¤º¸ Prednisolone is a synthetic glucocorticoid used as antiinflammatory or immunosuppressive agent. Prednisolone is indicated in the treatment of various conditions, including congenital adrenal hyperplasia, psoriatic arthritis, systemic lupus erythematosus, bullous dermatitis herpetiformis, seasonal or perennial allergic rhinitis, allergic corneal marginal ulcers, symptomatic sarcoidosis, idiopathic thrombocytopenic purpura in adults, leukemias and lymphomas in adults, and ulcerative colitis. Glucocorticoids are adrenocortical steroids and cause profound and varied metabolic effects. In addition, they modify the body's immune responses to diverse stimuli.
Protein Binding
Neomycin¿¡ ´ëÇÑ ´Ü¹é°áÇÕ Á¤º¸ Protein binding studies have shown that the degree of aminoglycoside protein binding is low and, depending upon the methods used for testing, may be between 0% and 30%. Prednisolone¿¡ ´ëÇÑ ´Ü¹é°áÇÕ Á¤º¸ Very high (>90%)
Neomycin¿¡ ´ëÇÑ Absorption Á¤º¸ Poorly absorbed from the normal gastrointestinal tract. Although only approximately 3% of neomycin is absorbed through intact intestinal mucosa, significant amounts may be absorbed through ulcerated or denuded mucosa or if inflammation is present. Prednisolone¿¡ ´ëÇÑ Absorption Á¤º¸ Readily absorbed by gastrointestinal tract, peak plasma concentration is reached 1-2 hours after administration.
Neomycin¿¡ ´ëÇÑ Biotransformation Á¤º¸ Neomycin undergoes negligible biotransformation after parenteral administration. Prednisolone¿¡ ´ëÇÑ Biotransformation Á¤º¸ Excreted in the urine as either free or glucoconjugate.
Toxicity
Neomycin¿¡ ´ëÇÑ Toxicity Á¤º¸ LD50 = 200 mg/kg (rat). Because of low absorption, it is unlikely that acute overdosage would occur with oral neomycin. However, prolonged administration could result in sufficient systemic drug levels to produce neurotoxicity, ototoxicity and/or nephrotoxicity. Prednisolone¿¡ ´ëÇÑ Toxicity Á¤º¸ LD50=500 mg/kg (oral, rat), short-term side effects include high blood glucose levels and fluid retention. Long term side effects include Cushing's syndrome, weight gain, osteoporosis, glaucoma, type II diabetes and adrenal suppression.
Drug Interactions
Neomycin¿¡ ´ëÇÑ Drug_Interactions Á¤º¸ Not Available Prednisolone¿¡ ´ëÇÑ Drug_Interactions Á¤º¸ Ambenonium The corticosteroid decreases the effect of anticholinesterasesEdrophonium The corticosteroid decreases the effect of anticholinesterasesNeostigmine The corticosteroid decreases the effect of anticholinesterasesPyridostigmine The corticosteroid decreases the effect of anticholinesterasesWarfarin The corticosteroid alters the anticoagulant effectAcenocoumarol The corticosteroid alters the anticoagulant effectDicumarol The corticosteroid alters the anticoagulant effectAnisindione The corticosteroid alters the anticoagulant effectMidodrine Increased arterial pressureAspirin The corticosteroid decreases the effect of salicylatesBismuth Subsalicylate The corticosteroid decreases the effect of salicylatesSalicylate-magnesium The corticosteroid decreases the effect of salicylatesSalicylate-sodium The corticosteroid decreases the effect of salicylatesSalsalate The corticosteroid decreases the effect of salicylatesTrisalicylate-choline The corticosteroid decreases the effect of salicylatesTalbutal The barbiturate decreases the effect of the corticosteroidSecobarbital The barbiturate decreases the effect of the corticosteroidQuinidine barbiturate The barbiturate decreases the effect of the corticosteroidPrimidone The barbiturate decreases the effect of the corticosteroidPhenobarbital The barbiturate decreases the effect of the corticosteroidPentobarbital The barbiturate decreases the effect of the corticosteroidMethylphenobarbital The barbiturate decreases the effect of the corticosteroidMethohexital The barbiturate decreases the effect of the corticosteroidHexobarbital The barbiturate decreases the effect of the corticosteroidHeptabarbital The barbiturate decreases the effect of the corticosteroidDihydroquinidine barbiturate The barbiturate decreases the effect of the corticosteroidButethal The barbiturate decreases the effect of the corticosteroidButalbital The barbiturate decreases the effect of the corticosteroidButabarbital The barbiturate decreases the effect of the corticosteroidAprobarbital The barbiturate decreases the effect of the corticosteroidAmobarbital The barbiturate decreases the effect of the corticosteroidChlorotrianisene The estrogenic agent increases the effect of the corticosteroidClomifene The estrogenic agent increases the effect of the corticosteroidDiethylstilbestrol The estrogenic agent increases the effect of the corticosteroidEstradiol The estrogenic agent increases the effect of the corticosteroidEstriol The estrogenic agent increases the effect of the corticosteroidConjugated Estrogens The estrogenic agent increases the effect of the corticosteroidEstrone The estrogenic agent increases the effect of the corticosteroidEstropipate The estrogenic agent increases the effect of the corticosteroidEthinyl Estradiol The estrogenic agent increases the effect of the corticosteroidMestranol The estrogenic agent increases the effect of the corticosteroidQuinestrol The estrogenic agent increases the effect of the corticosteroidEthotoin The enzyme inducer decreases the effect of the corticosteroidFosphenytoin The enzyme inducer decreases the effect of the corticosteroidMephenytoin The enzyme inducer decreases the effect of the corticosteroidPhenytoin The enzyme inducer decreases the effect of the corticosteroidRifampin The enzyme inducer decreases the effect of the corticosteroidItraconazole The imidazole increases the effect and toxicity of the corticosteroidKetoconazole The imidazole increases the effect and toxicity of the corticosteroid
Neomycin¿¡ ´ëÇÑ Description Á¤º¸ A component of neomycin that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed) Prednisolone¿¡ ´ëÇÑ Description Á¤º¸ A glucocorticoid with the general properties of the corticosteroids. It is the drug of choice for all conditions in which routine systemic corticosteroid therapy is indicated, except adrenal deficiency states. [PubChem]