Gram positive and Gram negative Amoxicillin-clavulanate Tazobactam-piperacillin Carbapenem: Ertapenen, Imipenem, Meropenem Cefuroxime Cefotaxime Ceftriaxone Anaerobes Amoxicillin-clavulanate Tazobactam-piperacillin Carbapenems Clindamycin Metronidazole Pseudomonas Tazobactam-piperacillin Carbapenems (except Ertapenem) Ceftazidime, Cefoperazone, Cefepime Gentamicin, Amikacin, Tobramycin Ciprofloxacin Colistin Aztreonam Only gram positive Vancomycin Teicoplanin Linezolid Daptomycin Only gram negative Ceftazidime Colistin Aztreonam “Non-culturable” bacteria Macrolides:…
Tag: General concepts
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Pharmacokinetics Mnemonics
ADME is the 4-letter acronym used to describe pharmacokinetics: ABCD is another 4-letter acronym used to describe pharmacokinetics: The most important pharmacokinetic parameters from a dosing point of view are: Vd = Volume of distributionD = DoseCo = Concentration in plasmaCL = ClearancekE = Elimination constantt1/2 = Half life In…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Cell-Cell or Interceullular Junctions
Junction Location Composition Function Remarks Tight junction (Zonula occludens) Epithelial cell-Epithelial cell Claudin and Occludin (attaches to cytoskeleton – actin filament) Prevents paracellular movement of solutes and diffusion Adherens junction (Zonula adherens) Epithelial cell-Epithelial cell E-cadherin (attaches to cytoskeleton – actin filament) Belt desmosome (Anchoring) Cadherins are Ca2+ depndend adhesion…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Competitive, Non-competitive and Uncompetitive Inhibitors
Vmax is the maximum velocity, or how fast the enzyme can go at full ‘‘speed.’’ Vmax is reached when all of the enzyme is in the enzyme–substrate complex. Km is the substrate concentration at which v = 1/2 Vmax. Km approximately describes the affinity of the substrate for the enzyme….
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Beta-oxidation of Fatty Acids : Simplified
Fatty Acid Activation (Cytoplasm) Before undergoing oxidation, fatty acid must be activated first by conversion into Acyl-CoA by the action of Fatty Acyl-CoA synthase (thiokinase). ATP is converted to AMP (not ADP) – 2 ATP equivalent used Uses Mg2+ as cofactor, Co-ASH and ATP Sites of Beta-oxidation A. Mitochondria: Short/Medium…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Fatty Acid Synthesis : Simplified
Enzymes: Fatty acid synthase (6 enzymes and 1 Acyl carrier protein molecule) Acetyl-CoA carboxylase (rate-limiting enzyme) Starting material: For palmitate synthesis: Acetyl-CoA For odd number carbon long chain fatty acid synthesis: Propionyl-CoA 2 Carbon donor: Malonyl-CoA (donates 2 C and 1 C is thrown out as CO2) Site: Cytosol Citrate…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Structure of Fatty acids and Derivatives : Simplified
Structure Saturated fatty acid: Single bond (“S” for saturated and single bond) Unsaturated fatty acid: Double bond(s), i.e. “D” for Double bonds, Decreased melting temperature and Decreased atherosclerotic risk (by decreasing LDL) Trans-fatty acid: Unsaturated fatty acid which act like saturated fatty acid (hydrogenation of unsaturated fatty acid) Nomencleture: C…
Clinical Skills and Approaches 
Eliciting Smoking and Alcohol History
Smoking History Ask: Have you ever smoked? If yes – Further ask: For how long? What form? (cigarettes, cigars, pipe, chewed) How much? Quantify smoking history: A ‘pack year’ is smoking 20 cigarettes a day (1 pack for one year) (Number of cigarettes smoked per day X Number of years…