<prompt> Tetracyclines are the first drug of choice for the following EXCEPTGranuloma inguinaleCholeraAtypical pneumoniaCommunity acquired pneumonia  <response>: Ans. d Community acquired pneumonia Ref. KDT, Pharmacology, 6th ed., 715Tetracyclines are 1st choice of drugs for: Lymphogranuloma venereum Lymes disease Brucellosis Relapsing feverMneumonic Lvbra CPG Rickettsial infection Atypical pneumonia due to chalmydia Cholera Plague prophylaxis Granuloma inguinale TETRACYCLINESMechanism of actionBacteriostatic; bind to 30S and prevent attachment of aminoacyl-tRNA; limited CNS penetration. Doxycycline is fecally eliminated and can be used in patients with renal failure. Do not take with milk Ca2, antacids Ca2 or Mg2, or iron-containing preparations because divalent cations inhibit its absorption in the gut.IndicationsBorrelia burgdorferi, M. pneumoniae. Drugs ability to accumulate intracellularly makes it very effective against Rickettsia and Chlamydia, Also used to treat acne.Advrese effectsGl distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity. Contraindicated in pregnancy.Mech of resistanceuptake or efflux out of bacterial ceils by plasmid-encoded transport pumps. Educational Points All tetracyclines excreted in urine except--Doxycycline Contraindicated in pregnancy Causes fetal tooth enamel dysplasia and bone growth disturbances Out-dated tetracycline -can cause Fanconis syndrome pseudotumor cerebri Demeclocycline and Doxycycline -Phototoxicity . Minocycline -Vestibulotoxicity Demeclocycline -ADH-like action Block protein synthesis at 30S ribosomal subunit-Aminoglycosides, tetracyclines. 