Antibiotic Therapy

<p>1 hour</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Cell wall, ribosomes, DNA replication, DNA gyrases, Metabolic pathways, Cell. membrane function</p> Signup and view all the answers

<p>Inhibit cell wall synthesis by preventing cross linking of peptidoglycan - bactericidal</p> Signup and view all the answers

<ul> <li>β lactam</li> <li>Very few side effects</li> <li>Range from narrow to broad spectrum</li> <li>Excreted (rapidly) via kidneys</li> <li>Safe in pregnancy</li> </ul> Signup and view all the answers

<p>-Patients can be hypersensitive (allergic). -Rapid excretion via the kidneys. This results in frequent dosing -Resistance- Due to a long history of clinical use, many microbes have been exposed to these compounds and some resistant strains have been selected for.</p> Signup and view all the answers

<ol> <li>Benzylpenicillin- penicillin G, intravenous IV</li> <li>Phenoxymethyl penicillin- penicillin V, oral</li> <li>Benzathine penicillin- long acting, intramuscular (IM)</li> </ol> Signup and view all the answers

<p>Penicillin V is effective on a narrow range of largely Gram +ve bacteria. Absorbed through intestine Sensitive to stomach acid (30 mins before meal or 3 hours after) Peak plasma concentration 30-60 minutes after taking 75-90% binds to plasma proteins Serum levels maintained for 30-60 minutes</p> Signup and view all the answers

<p>Amoxicillin is administered via IV or orally. It is a safe, well tolerated antibiotic. It is well-absorbed when given orally. It has a low binding ability to plasma proteins (longer half life) and good tissue distribution. Its effectiveness is challenged by spread of beta-lactamases.</p> Signup and view all the answers

<p>Amoxycillin has a broad spectrum effect across Gram +ve and Gram -ve bacteria. Absorbed through the intestine Stable in the presence of stomach acid Peak plasma concentration 60-120 minutes after taking Wide tissue distribution and it also has the capacity to enter the CSF (cerebrospinal fluid) if meninges are inflamed. 20% binds to plasma proteins Plasma half life is 60 minutes</p> Signup and view all the answers

<ol> <li>Inhibitory/ bactericidal</li> <li>Time Dependant action (peak plasma concentration)</li> <li>Spectrum (Gram +ve or -ve)/ Anaerobic bacteria</li> <li>Absorption- Peritoneal versus IV, where it gets absorbed, acid sensitivity</li> <li>Distribution- Plasma binding proteins, GI/urinary tract, environment permissive for activity 6)Elimination via liver or kidney</li> </ol> Signup and view all the answers

<p>Kills bacteria, selective toxicity, good tissue distribution, long half life, peritoneal absorption, no significant drug interactions.</p> Signup and view all the answers

<p>Cephalosporins inhibit cell wall synthesis and are bactericidal. Modified beta-lactam It has a longer half life in plasma Excreted via kidneys and urine Has a few side effects, reduced allergy Safe in pregnancy Narrow Gram -ve to broad (3rd) and extended spectrum (4th) Relatively resistant to beta lactamases</p> Signup and view all the answers

<p>Cephalosporins are broad spectrum antibiotics, which significantly affect the normal bowel flora. They kill the normal gut bacteria and allow the overgrowth of C. difficile which causes bad gastroenteritis. Their use in Tayside is very restricted.</p> Signup and view all the answers

<p>1)They are not Beta lactic antibiotics. 2)Bactericidal 3)Excreted via the kidneys and urine; toxic levels of vancomycin in the blood can build up in patients who have kidney failure- causes red man syndrome 4) Limited to bacteria with Gram positive cell wall 5) Oral vancomycin can target Gram +ve GI microbes as it builds up in intestines. It doesn't get absorbed too easily and therefore is effective against C. difficile. 6) It has no activity against Gram -ve organisms.</p> Signup and view all the answers

<p>Antibiotics that inhibit protein synthesis do so by attaching to bacterial ribosomes, which are structurally different from mammalian ribosomes.</p> Signup and view all the answers

<p>Usually, protein synthesis can resume when the antibiotic is removed so most of these antibiotics (macrolides, tetracycline) are bacteriostatic. However, in aminoglycosides, the binding of these antibiotics to the ribosomes is lethal. This is what makes it bactericidal.</p> Signup and view all the answers

<ol> <li>Aminoglycosides e.g. Gentamicin</li> <li>Tetracyclines e.g. Doxycycline/Minocycline</li> <li>Macrolides e.g. Erythromycin</li> </ol> Signup and view all the answers

<p>Aminoglycosides are protein synthesis inhibitors which are not absorbed from the gut and therefore must be given in IV.</p> <ol> <li>Binds irreversibly to ribosomes inhibiting protein synthesis and thus it is bactericidal.</li> <li>Active mostly against Gram -ve aerobic bacteria. (coliform and Pseudomonas aeruginosa). It is effective in hospital for treating life threatening gram -ve infection.</li> <li>Excreted in urine</li> <li>Excessive levels in the serum would cause damage to kidney and the 8th cranial nerve- need to monitor blood levels of aminoglycosides.</li> </ol> Signup and view all the answers

<p>Tetracyclines are protein synthesis inhibitors that are bacteriostatic in nature.</p> <ol> <li>Broad spectrum- useful against intracellular bacteria and atypical bacteria like chlamydia</li> <li>Resistance- increasing as more is being used</li> <li>Adverse effects- Destruction of normal intestinal flora resulting in increased secondary infections. Staining and impairment of the structure of bone and teeth, restricted use in infants, children and pregnancy.</li> </ol> Signup and view all the answers

<p>Tetracyclines are actively transported into the cell. It binds to 30S subunit and prevents attachment of tRNA to acceptor sites. It stops the chain elongation. Doxycycline and Minocycline provide more efficient absorption- lower concentrations in gut, less disturbance, higher concentration in serum.</p> Signup and view all the answers

<p>Macrolides are</p> <ol> <li>bacteriostatic</li> <li>commonly prescribed for Penicillin allergy and intracellular pathogens.</li> <li>This group of antibiotics is excreted via the liver, biliary tract and into the gut. They are not excreted in the urine.</li> <li>Lipophilic antibiotics pass through cell membranes easily.</li> <li>Useful in treating infections where intracellular bacteria hide from host's immune system 6)Safe in pregnancy</li> </ol> Signup and view all the answers

<p>Erythromycin, Clarythromycin (Gram -ve) and Azithromycin (Gram +ve)</p> Signup and view all the answers

<p>It binds to the 50S subunit and blocks translocation- therefore no release of peptides.</p> Signup and view all the answers

<p>Fluoroquinolones (for Gram -ve and Gram +ve) Metronidazole (for Anaerobes and protozoa) Trimethoprim (for primary use in urinary tract infection)</p> Signup and view all the answers

<ol> <li>Bactericidal</li> <li>Good intracellular activity</li> <li>Activity on infection of bones, UTIs, community acquired pneumonia</li> <li>Effective on gram -ve bacteria mostly</li> </ol> Signup and view all the answers

<p>Binds to the A subunit of DNA gyros (topoisomerase) and prevent supercoiling of DNA. It directly inhibits DNA synthesis.</p> Signup and view all the answers

<p>Use of broad spectrum antibiotics is now severely restricted to reduce the risk of C. difficile GI infection, especially in elderly patients.</p> Signup and view all the answers

<p>Ciprofloxacin, moxiflocin, levofloxacin</p> Signup and view all the answers

<p>1)It has good activity against anaerobe bacteria and parasites/ protozoa. 2) Administered via Oral or IV methods 3) Resistance is rare 4) Adverse reactions with alcohol- furred tongue etc.</p> Signup and view all the answers

<p>The drug is activated by reduction in strict anaerobes and it forms a toxic intermediate that induced DNA strand breakage.</p> Signup and view all the answers

<ol> <li>Active against some Gram -ve and Gram -ve bacteria</li> <li>Common for acute UTI e.g. E. coli</li> <li>Excreted via the urine</li> <li>Administered orally (on its own) or Administered in a combination with a sulphomethoxazole (a sulphonamide) in oral and IV form.</li> </ol> Signup and view all the answers

<p>It inhibits Folic acid synthesis as it is a key intermediate metabolism. Folic acid vitamin is required for synthesis of key cellular components like thymidine, purines etc.</p> Signup and view all the answers

<p>hypersensitivity/skin reactions</p> Signup and view all the answers

<p>cholestatic jaundice</p> Signup and view all the answers

<p>C. difficile colitis</p> Signup and view all the answers

<p>GI disturbances, hepatitis, Q-T interval</p> Signup and view all the answers

<p>Q-T interval, convulsions, tendonitis</p> Signup and view all the answers

<p>nephrotoxicity/ototoxicity</p> Signup and view all the answers

<p>‘red man’ syndrome</p> Signup and view all the answers

<p>hepatotoxicity, staining teeth, photosensitivity, dysphagia</p> Signup and view all the answers

<p>peripheral neuropathy, pulmonary fibrosis</p> Signup and view all the answers

<p>aplastic anaemia, grey baby</p> Signup and view all the answers

<p>blood dyscrasias, MAOI, optic neuropathy</p> Signup and view all the answers

<p>hepatotoxicity</p> Signup and view all the answers

<p>Stevens-Johnson syndrome, blood dyscrasias</p> Signup and view all the answers

<p>blood dyscrasias</p> Signup and view all the answers

<p>Enzyme inhibitors interact with erythromycin, clarithromycin, isoniazid, metronidazole, ciprofloxacin.</p> Signup and view all the answers

<p>Rifampicin is affected by enzyme inducers.</p> Signup and view all the answers

<p>Antacids/calcium can reduce the absorption of tetracyclines and quinolones.</p> Signup and view all the answers

<p>Entero-hepatic cycling can lead to contraceptive failure when taken with broad-spectrum antimicrobials and oral contraceptives.</p> Signup and view all the answers

<p>Taking broad-spectrum antimicrobials with warfarin leads to increased INR.</p> Signup and view all the answers

<p>Metronidazole can cause a disulfiram-like interaction with alcohol.</p> Signup and view all the answers

<p>Quinolones can interact with steroids, leading to tendonitis, and with NSAIDs, leading to convulsions.</p> Signup and view all the answers

<p>Macrolides and Quinolones can interact with Q-T prolonging drugs.</p> Signup and view all the answers

<p>Aminoglycosides/glycopeptides/colistin with loop diuretics or ciclosporin or tacrolimus - nephrotoxicity</p> Signup and view all the answers