BP SBA Flashcards
Enzyme that converts paracetamol to reactive metabolite -
CYP2E1; the reactive metabolite is NAPQI
Depleted in paracetamol overdose -
glutathione -S - transferase
Bacterial protein synthesis inhibition
macrolide e.g. erythromycin (target the 50S ribosomal subunit - involved in translocation) or tetracyclines (target the 30S ribosomal subunit involved in elongation)
Which receptors mediate sympathetic effects -
adrenoreceptors
What receptors mediate parasympathetic effects? -
muscarinic acetylcholine receptors (post synaptically) and nicotinic receptors (presynaptically); NMJ is also nicotinic presynaptic
Acyclovir
viruses specifically herpes simplex - it inactivates its DNA polymerase which stops DNA synthesis
effect of a1, a2, b1, b2
should know this
Warfarin inactivated to result in transformation of ketone to hydroxyl group
phase I metabolism (we do not have this detail in our lectures)
Insulin release by blocking K channels -
Sulphonylureas (e.g. glibenclamide) block the KATP channels so cause depolarisation and increase insulin secretion independently of glucose levels (need partially functioning β cells).
What do polyenes e.g. nyasatins target
binds to ergosterol and in high enough concentrations cause pore formation which leads to potassium leakage
What type of data would be used to generate a graded response curve?
individual Response of a particular system: isolated tissue, animal or patient. Measured against agonist concentration
Quantal?
population Drug doses (agonist or antagonist) required to produce a specified response determined in each member of a population
What drugs are highly protein bound and poorly absorbed? -
warfarin (the one in the notes) Ceftriaxone,
found at lower concentration in filtrate than in plasma
Drug Vd question:
initial dose/T0
What hormone is affected in the contraceptive pill?
Oestrogen and progesterone
What hormone is affected in in the morning after pill?
Higher doses of oestrogen and progesterone
Paracetamol metabolism -
• Mainly by conjugation with sulphate and glucuronic acid
• Only a minor proportion metabolised by CYP450 to a toxic metabolite
• Toxic metabolite normally detoxified by glutathione (another Phase II reaction)
• NAPQI will bind to heaptocyes and will damage the liver cells
- This is conjugated to eliminate the mercapturic acid from the body
• Alcohol can increase the amount Of enzyme working to produce the NAPQ
anticoagualnts
•Anticoagulation usually starts with a combination of heparin and an oral anticoagulant e.g. warfarin
ORAL ANTICOAGULANTS - Warfarin
•Warfarin massively prescribed
-inhibit hepatic synthesis of vitamin K1 dependent clotting factors II, VII, IX & X
-VitK driver of coagulation site
Parenteral anticoagulants - HEPARIN
Ability to bind to antithrombin which allows interaction
• Heparin can bind to thrombin and antithrombin to inactive thrombin
• requires antithrombin III (a2 globulin) for activity
• AT III inactivates thrombin, IX, X, XI & XII
- Stops conversion of soluble clot into insoluble clot
Efficacy
Efficacy - maximum response achievable from an applied or dosed agent, for instance, a small molecule drug
Agonist concentration/response graphs
see notes
Which receptor is affected by a drug that stops polarisation at the NMJ?
- (muscle type) nicotinic receptors agonists and antagonists (suxemethonium and tubocurarine respectively)
Which reaction is part of phase one metabolism?
usually consist of oxidation (most common), reduction or hydrolysis
Purpose of conjugation
- further decreases lipid solubility and almost always results in pharmacologically inactive metabolites
What effects volume of distribution
Membrane permeability Blood perfusion Lipid solubility pH-pKa Plasma protein binding Tissue binding
Definition of phobia?
- Fear of object or situation
What effects drug clearance from body?
kidney function, protein binding, urine pH and urine flow.
VOD is affected by?
tissue binding- drugs which accumulate in tissues have a large volume of distribution.
Size - Drugs confined to the plasma compartment are too large to cross the capillary wall easily e.g. heparin