Which drug acts by inhibiting protein synthesis?
Correct Answer: Erythromycin
Description: Ref: katzung 11th ed. P. 805Explanation: (See the following Table) SubclassMechanism of ActionEffectsClinical applicationPharmacokinetics, Toxicities. InteractionsTetracyclinesTetracyclinePrevents bacterial protein synthesis by binding to the 30S ribosomal subunitbacteriostatic activity against susceptible bacteriaInfections caused by mycoplasma, chlamydiae. nckettsiae, some spirochetes* malaria * H pylori*acneOral * mixed clearance (half-life 8 h)* dosed every! 6h * divalent cations impair oral absorption * Toxicity: Gastrointestinal upset, hepatotoxicity, photosensitivity, deposition in bone and teethMacrolidesErythromycinPrevents bacterial protein synthesis by binding to the 30S ribosomal subunitBacteriostatic activity againsl susceptible bacteriaCommunit-acquired pneumonia * pertussis corynebaclerial. and chlamydial infectionsOral, IV * hepatic clearance (half-life 1.5 h) * dosed every 6h 'cytochrome P45Q inhibitor * Tixicity: Gastrointestinal upset, hepatotoxicity, QTc prolongationLincosamideClindamycinPrevents bacterial protein synthesis by binding to the 50S ribosomal subunitBacteriostatic activity against susceptible bacteriaSkin and soft tissue infections * anaerobic infectionsOral. IV * hepatic clearance (half-life 2.5 h) * dosed every 6-8 hours * Toxicity: Gastrointestinal upset, difficile colitisStreptograminsQuinupristin-dalfopristinPrevents bacterial protein synthesis by binding to the 50S ribosomal subunitRapidbactericidal activity against most susceptibleoacteriainfections caused by staphylococci or vancomycin-resistant strains of faeciumIV * hepatic clearance * dosed every 8-12 h * cytochrome P450 inhibitor * Txicity: severe infusion-related myalgias and arthralgiasChloramphenicolPrevents bacterial protein synthesis by binding to the 5OS ribosomal subunitBacteriostatic activity against susceptible bacteriaUse is rare in the developed world because of serious toxicitiesOral, IV * hepatic clearance (half-life 2.5 h) * dosage is 50-100 mg/kg.'d in four divided doses * Toxicity: Dose - related anemia, idiosyncratic aplastic anem a. gray baby syndromeOxazolidinonesLinezolidPrevents bacterial protein synthesis by binding 1c the 23S ribosomal RNA of 50S subunitBacteriostatic activity against susceptible bacteriaInfections caused by mathicrllin-resisfant staphylococci and vaneomycin- resistant enterococcioral, IV * hepatic clearance (half-life 6 h) dosed twice-daily * Toxicity: Duration dependent bone marrow suppression, neuropathy, and optic neuritis * serotonin- syndrome may occur when coadministered with other serotonergic drugs (e.g. selective serotonin reuptake inhibitors)Drugs acting on 50 S-(remember CELLS)-"Chloramphenicol, erythromycin, lincosamides, linezolide, streptogramin
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