BP SBA Flashcards by Zaira Sattar

Enzyme that converts paracetamol to reactive metabolite -

CYP2E1; the reactive metabolite is NAPQI

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Depleted in paracetamol overdose -

glutathione -S - transferase

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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)

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Which receptors mediate sympathetic effects -

adrenoreceptors

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What receptors mediate parasympathetic effects? -

muscarinic acetylcholine receptors (post synaptically) and nicotinic receptors (presynaptically); NMJ is also nicotinic presynaptic

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Acyclovir

viruses specifically herpes simplex - it inactivates its DNA polymerase which stops DNA synthesis

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effect of a1, a2, b1, b2

should know this

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Warfarin inactivated to result in transformation of ketone to hydroxyl group

phase I metabolism (we do not have this detail in our lectures)

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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).

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What do polyenes e.g. nyasatins target

binds to ergosterol and in high enough concentrations cause pore formation which leads to potassium leakage

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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

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Quantal?

population Drug doses (agonist or antagonist) required to produce a specified response determined in each member of a population

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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

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Drug Vd question:

initial dose/T0

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What hormone is affected in the contraceptive pill?

Oestrogen and progesterone

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What hormone is affected in in the morning after pill?

Higher doses of oestrogen and progesterone

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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

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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

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Efficacy

Efficacy - maximum response achievable from an applied or dosed agent, for instance, a small molecule drug

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Agonist concentration/response graphs

see notes

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Which receptor is affected by a drug that stops polarisation at the NMJ?

(muscle type) nicotinic receptors agonists and antagonists (suxemethonium and tubocurarine respectively)

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Which reaction is part of phase one metabolism?

usually consist of oxidation (most common), reduction or hydrolysis

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Purpose of conjugation

further decreases lipid solubility and almost always results in pharmacologically inactive metabolites

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What effects volume of distribution

Membrane permeability
Blood perfusion
Lipid solubility
pH-pKa
Plasma protein binding
Tissue binding

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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

Adrenaline is given with LA why?

because it is a vasoconstrictor – reduces bleeding during extractions and prevents the LA solution from diffusing away from the area where it is needed

1)Which receptors are associated with sympathetic response?

A1, a2, b1, b2, b3

Which drugs prevent ovulation?

Combined pill

1)Which drugs induce abortion?

Progesterone antagonist

Comparing different graphs?

Competitive agonist, partial agonist…

Which drug inhibits bacterial protein synthesis?

Macrolides: erythromycin (translation) and tetracycline (elongation)

Which is aciclovir best against?

Viruses

Why cant you take metronidazole with alcohol?

enzyme (aldehyde dehydrogenase) which breaks down acetaldehyde it down is inhibited by metronidazole. accumulation of acetaldehyde = hepatocyte damage

phase 1 reaction?

• usually consist of oxidation (most common) reduction or hydrolysis • cytochromes P450 (important group of enzymes) & plasma cholinesterase involved • often introduce/expose a functional group e.g. OH (functionalisation) • decrease lipid solubility but may increase pharmacological/toxicological activity

What does penicillin target?

Peptidoglycan cell wall

parasympathetic receptor?

cholinergic muscarinic receptors M1 M2 M3

Which of these block Na channel to stimulate insulin release?

Sulphonylureas (e.g. glibenclamide) 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  cells).

Which of these causes a depolarizing block?

nicotinic agonists •(suxemethonium) anticholinesterase at large dose (neostigmine, organophosphates)

What is the disorder in which someone has an excessive/unreasonable fear?

A Phobia

Feature vs identity – which error?

Phenomenist error making erroneous assumptions about the identity of an object based on its external features Intellectual realism error making erroneous assumptions about the external features of an object based on its identity

which drugs precipitates an asthmatic attack?

NSAIDS or beta blockers notes say Propranolol is (b1 b 2 antagonist) bad for asthma so should be beta blocker as answer

Active compound of acyclovir?

Acyclovir triphosphate

Drug metabolism statement.

Calculation for Vd – dose / [plasma]

What is given to overcome over anti-coagulation

vitamin K1 warfarin can inhibit hepatic synthesis of vitamin K1 dependent clotting factors II, VII, IX & X

GI transport is independent of ?

Substance is oxidised and becomes more lipophilic, this is an example of…?

Phase 1 metabolism

Lidocaine, a local anaesthetic, targets…?

Na+ voltage gates channels

Parasympathetic effect Muscarinic agonists

* Increase in Pupil constriction (contraction of constrictor pupillary muscle) * Decrease in focal length of the lens (contraction of ciliary muscle) * Bronchoconstriction * Decrease in cardiac output, (rate & force) * Increase GI motility * Increase exocrine gland secretion (sweating salivation, bronchiol secretion)

What blocks depolarisation in neuromuscular junction?

Botulism

Rate of renal excretion is related to…?

Lipid solubility

Anxiolytics target which receptors?

GABA

What mechanism moves drugs from blood to tissues?

Distribution

2)What to polyenes/nystatins target?

It’s an antifungal drug targeting sterol in the fungus’ cell walls, ergosterol - pores

What class of drugs are highly protein bound and poorly absorbed?

Antifolates

Drug Vd question?

Make sure you know how to convert ug to mg = dose/conc at zero

What hormone is affected in the contraceptive pill?

Progesterone or both progesterone and estrogen.

What enzyme converts paracetemol in a phase 1 reaction?

Glucuronidation UDP GLUCURONYLTRANSFERASE

2019 cs starts here neonates are highly susceptible to drug interactions, why is this?

lack of conjugating activity is most important (lack of use of morphine labour) also: have poor glomerular filtration rate have a low activity with regards to: CYPs, glucornyl transferase, N-acetyltransferase

What is the biological target of metronidazole?

Inhibits bacterial DNA synthesis/degrades DNA

Why is aciclovir is most suited to its function?

High specificty to herpes simplex so only toxic to infected cell

29. What is the effect of LA independent of?

add

30. Drug metabolism statement – which is most appropriate?

- Body inactivates the drug through enzymatic modification. Enzymes will destroy the drug compound and start process of elimination.

1. TCAs statement – which is most appropriate?

SSRIs and TCAs exhibit equivalent antidepressant efficacy SSRIs have a better adverse side effect profile than TCAs They block 5-HT and noradrenaline

A woman has been taking benzodiazepines for a long time, what is she most likely to experience when she stops taking them?

Dependence? can t find anything specfiic in lectures (sexual fantasies mentioned but not sure if this is a withdrawal effect

33. How does a specified oral anticoagulant work – mechanism of action?

warfarin - inhibit hepatic synthesis of vitamin K1 dependent clotting factors II, VII, IX & X via inhibition of vitamin K reductase

What substance is responsible for increasing insulin production?

Sulphonylureas block the KATP channels so cause depolarisation and increase insulin secretion independently of glucose levels (need partially functioning cells).