Block 9 Pharmacology Flashcards
Paracetamol
Analgesic and Anti-pyretic with some anti-inflammatory efffect
- Used when NSAIDs can’t be.
MOA Inhibition of COX-1,2,3 > inhibition of prostaglandin synthesis
S/E - toxic dose cause nausea and vomiting then 24hrs later potentially fatal liver toxicity
Amoxicillin
Beta-lactam antibiotic (bactericidal) -> interferes with bacterial cell wall synthesis
Uses: Active against wide range of Gram+, and a limited range of Gram-bacteria
MOA: inhibit enzymes that crosslinks peptidoglycan within cell wall -> inhibits cell wall synthesis -> causes cell lysis
Resistance - Not effective against staph (due to β-lactamase- resistant bacterial enzyme) and streptococci (have impaired β-lactam binding) -> Amoxicillin can be combined with clavulanic acid (β-lactamase inhibitor) to overcome resistance mediated through β-lactamase production -> Co-amoxiclav
Methicillin
Beta lactam antibiotic - A transpeptidase inhibitor
Uses: Narrow spectrum beta-lactam antibiotic against gram+ bacteria
MOA: Inhibits bacterial cell wall synthesis, via inhibition of transpeptidase enzyme used for cross-linking peptidoglycan
-Flucloxacillin and Dicloxacillin used in clinic.
Cefuroxime
Cephalosporin (type of beta-lactam antibiotic) -> Transpeptidase inhibitor (Bactericidal)
Uses: Highly active against gram- cocci/ bacilli, anaerobes more than gram+ cocci/bacilli
Uses: sinusitis, ear infections, lower respiratory tract infections, urinary infections and gonorrhea
MOA: inhibits cell wall synthesis, leading to bacterial lysis (similar to penicillin)
-Can cross the blood brain barrier.
-There is resistance to Cefuroxime in Listeria and MRSA
Benzylpenicillin
Beta lactam antibiotic - A transpeptidase inhibitor (bactericidal)
Uses: target usually gram+ organisms but can target gram-aerobic and anaerobic bacteria
Uses: streptococcal, gonococcal, meningococcal infections; also anthrax, dipththeria, gas gangrene
MOA: binds penicillin proteins that then causes the inhibition of cell wall synthesis -> cell lysis
Oxytetracycline
A 30s inhibitor ( tetracycline antibiotic) - bacteriostatic
-A broad-spectrum antibiotic
Uses: infections caused by a variety of Gram positive and Gram negative microorganisms including M. pneumoniae, Pasteurella pestis,E. coli, H. influenzae (respiratory infections), and Diplococcus pneumoniae.
Uses: Used to treat many infections, including acne.
- MOA inhibition of cell growth by binding to the 30S ribosomal subunit -> Prevents tRNA from binding ribosome site -> INHIBITS translation
- Lipophilic = can pass through the cell membrane or passively diffuse through porin channels in the bacterial membrane.
Erythromycin
A 50s inhibitor (Macrolide Antibiotic) -> bacteriostatic/bacteriocidal
Uses: to treat multiple infections (respiratory infections, syphillis, skin infections, whooping cough and chronic prostatitis) in pts allergic to penicillin
- Effective ONLY against actively dividing organisms.
MOA: reversibly binds to the 50S subunit of ribosomes -> blocks the translocation of peptides from the acceptor site to the donor site -> INHIBITS PROTEIN SYNTHESIS
Gentamicin
A 30S inhibitor (aminoglycoside antibiotic)
Uses: A broad spectrum antibiotic
Uses: infections involving Gram- bacteria (such as Pseudomonas, Acinetobacter, and Enterobacter)
- septicaemia, meningitis, pyelonephritis, endocarditis and pneumonia
- can be used to treat mycobacteria (TB) and gram+ infections.
MOA: bind to the bacterial 30S ribosomal subunit, INHIBITS PROTEIN SYNTHESIS
- NOTE: aminoglycosides can cause ototoxicity and nephrotoxicity
Rifampicin
A RNA/DNA polymerase inhibitor (Ansamycin antibiotic) -> Bactericidal
Uses: A broad spectrum antibiotic (targets both gram+ and gram- bacteria)
Uses: TB, Leprosy. Prophylaxis for meningococcal meningitis, and H. influenzae. Also used for brucellosis, endocarditis, legionnaires’ disease, serious staphylococcal infections
MOA: inhibition of DNA-dependent RNA polymerase -> prevents RNA synthesis -> cell death
NOTE: Due to increased resistance Rifampicin is restricted to mainly mycobacterial infections.
Trimethoprim
Folate antagonist (Antibiotic)
Uses: UTIs, acute and chronic bronchitis, prostatitis
MOA: binds to DHF synthetase enzyme -> prevents formation of tetrahydrofolate-> less thymidine synthesis -> INHIBITION OF BACTERIAL DNA SYNTHESIS
-Trimethoprim has higher affinity for bacterial dihydrofolate reductase that human form of the enzyme
Sulfamethoxazole
A sulfonamide antibiotic (PABA analogue)
Uses: to treat bronchitis, prostatitis and urinary tract infections and combined with trimethoprim to treat pneumocystis pneumonia, toxoplasmosis & nocardiosis
MOA: Competitively inhibits DHF synthetase -> inhibits tetrahydrofolate synthesis -> less thymidine synthesis -> INHIBITION OF BACTERIAL DNA SYNTHESIS
Trimethoprim and sulfamethoxazole are commonly used in combination -> they target the same pathway and their synergistic effects reduce the development of bacterial resistance
Vancomycin
Glycopeptide antibiotic -> affects cell wall synthesis
Uses: Listeria monocytogenes, Strep. pyogenes, Strep. pneumoniae (including penicillin-resistant strains) BUT NOT active against gram negative bacilli, mycobacteria, or fungi
MOA: incorporation of NAM and NAG subunits into peptidoglycan cell wall matrix -> affects cell wall permeability -> cell lysis
NOTE used as a ‘last resort drug’ after other antibiotics have failed as no cross-resistance with other ABs
Colistin
A polymyxin polypeptide antibiotic -> bactericidal
Uses: acute or chronic infections due to sensitive strains of certain gram-negative bacilli (Particularly) Pseudomonas aeruginosa)
MOA: Polymyxins are polypeptides that disrupt bacterial cell membrane -> changes cell permeability -> cell lysis
The use of polymyxins is coming back after multi-drug resistance gram- bacteria against penicillins and cephalosporins
Ciprofloxacin
Quinolone antibiotic (Topoisomerase II inhibitor) -> bactericidal
Uses: Broad spectrum AB used against a wide range of gram- and gram+ bacteria. Infections of the urinary tract/ GIT and bones & joints. Also resp. infections not caused by pneumococci and for gonorrhoea and septicaemia
MOA inhibits topoisomerase II (DNA gyrase) which produce supercoils in DNA that is needed for replication -> INHIBITS DNA SYNTHESIS
Fusidic acid
Translocation inhibitor (antibiotic) -> Bacteriostatic
Uses: to treat staphylococcal bacterial skin and eye infections (used as cream/eyedrops)
MOA inhibits translocation during protein synthesis
Aspirin
NSAID
Uses: Analgesic, antipyretic and anti-inflammatory effects. anti-platelet -> inhibits platelet aggregation
MOA: Irreversibly inhibits COX 1 and COX2 enzymes to decrease formation of prostaglandins and thromboxanes from arachidonic acid
Ibuprofen
NSAID
Uses: Infammatory conditions (e.g. rheumatoid disease, osteoarthritis, musculo-skeletal disorders); dysmenorrhoea
MOA Reversible inhibition of COX1 and weak inhibition of COX2 -> decreasing prostaglandin synthesis -> reduced inflammation, pain, fever and swelling. Anti-pyretic effect possibly due to effect on hypoT - > leading to increased peripheral blood flow, vasodilation which allows for heat dissipation