Pharmacology Flashcards
Define clinical pharmacology
the application of pharmacological principles and methods in the medical clinic or towards patient care
Define toxicology
The study of adverse affects, molecular targets, and characterisation of drugs or any chemical substance in excess (the dose makes the poison)
Define Agonistic drugs
a drug that binds to and activates a receptor to cause a response
Define antagonistic drugs
a drug that blocks or dampens a biological response by binding to a blocking a receptor
Define pharmacokinetics
[what the body does to the drug] how the drug is absorbed, distributed, moved around, metabolised and excreted
Define pharmacodynamics
[what the drug does to the body] — How well the targets (e.g. receptors, ion channels, enzymes, and immune system components) respond to the drug
Name the axis on a dose-response graph
increasing dosage across the X axis and increasing response across the Y axis
What gradient depicts a margin of safety on a dose response graph?
The higher the gradient, the less the margin of safety as changing the dose a little can have a large response change
What is the ED50
a value showing the dose required to produce 50% of the maximum response
Define Potency
the amount of drug necessary to produce a certain effect (often used in comparing ED50 values)
Define Efficacy
the maximum response that a given drug will produce, irrespective of dose (Emax)
What are the 4 main types of targets for drug action?
Receptors, Enzymes, Transporters and Ion Channels
What is a prodrug?
Prodrugs are inactive precursors that are metabolised to active metabolites (e.g. L-dopa is converted to dopamine)
Explain the mechanism of ligand gated channels
it permits the movement of positively charged ions into the synaptic cleft of the cytoplasm in response to the binding of a chemical messenger ligand
What are the 4 stages of drug disposition (ADME)
Absorption: the passage of a drug from its site of administration into the plasma
Distribution through the blood plasma and different body tissues
Metabolism: the chemical changes of the substance in the body
Excretion or elimination of the substance or the products of its metabolism
What is an analgesic?
A drug used to relieve pain
True or false: analgesics remove sensation
False, they just remove pain not full sensation
During pain perception, what is released into the blood plasma and what does it trigger?
Bradykinin is released, which causes the release of prostagladins and substance P which stimulates the nervous system
What are the most common types of analgesics given for toothache or post dental surgery
Non-opoid analgesics
True or false: ibuprofen causes xerostomia
True
Name three examples of Corticosteroids and what they do
Orabase-HCA, Oracort, Oralone, they are all anti-inflammatory
Explain pharmacogenetics
the identification of genetic variants that affect the responses to medications in patients
What is the term for when patients do not respond to a drug because of their particular genetic makeup?
Refractory
what tpyes of drugs are particularly affected by polymorphism?
Drugs involved in the liver, with proteins and enzymes
What is codiene?
opiate used to treat mild to moderate degrees of pain
What is the name of the catalyst involved in codiene and what does it do?
CYP2D6, as codiene is a prodrug this catalyses its breakdown into morphine in the liver
Give an example for the most common intravenous sedation drugs
Midazolam, which is in the branch of benzodiazepines, which works as a general CNS (HR included) depressant
What does midazolam bind to to work?
the GABAa receptor on the GABA neurotransmitter, which opens a chloride ion channel to increase -ve charge and depress the nervous system AP
what are the phases of midazolam recovery?
- recovery from sedation, 2. recovery from psycho-motor impairment. so cant drive or operate machinery directly after even if you can get up and walk e.t.c
What is the most popular antibiotic prescribed by dentists?
amoxicillin, which is a type of penicillin
What antibiotic is particularly used for anaerobic bacteria and protozoa?
Metronidazole, a nitroimidazole antibiotic medication
What happens if one takes alcohol on metronidazole?
a disulfiram-like reaction with effects that can include nausea, vomiting, flushing of the skin, tachycardia (accelerated heart rate), and shortness of breath
Antidepressants can cause ____
Xerostomia by blocking acetylcholine action which blocks saliva/mucous production
Nitroglycerin is a ______ used to treat _____ that can also cause _____
Nitrates, Agina, headaches that can be referred to as toothache (it is a vasodilator, causes blood vessel swelling)
What is the primary oral effect of heorin?
Dental decay
What are people who are type 1 diabetic more at risk of?
Dry mouth, Gum inflammation, Poor healing of oral tissues, Thrush (yeast thrives on the high levels of sugar in the saliva of people with uncontrolled diabetes), getting hypoglycemia
What are examples of complications from use of steroids?
Oral yeast infections, blood blisters, adrenal supression
What happens when L.A is given when the patient is on beta blockers?
B inhibit hepatic enzymes, resulting in the reduced metabolism of lidocaine (local anaesthetic), could lead to increased serum levels and, possibly, toxicity of lidocaine.
With non-selective blockers, acute hypertensive episodes if they receive vasopressors contained in local anaesthetics, e.g. epinephrine
What are examples of complications from use of bisphosphonates?
they are used to prevent bone resorption so after extraction can lead to exposure of dead bone (osteonecrosis) which causes pain and an attachment surface
What is Steven-John’s syndrome and what are it’s symptons?
hypersensitivity complex causes by a severe allergic reaction to medication. It causes massive ulcers and lesions on the lips and mucous membranes, making it hard to eat/drink/speak
What is the difference between anaesthesia and analgesia?
Analgesia is the removal of pain, anaesthetics is the removal of all sensation
Give some ‘unconventional’ examples of local anaesthesia
Pressure, hypoxia, extreme cooling
Give 5 examples of methods of administering anaesthetics
Nerve block, subcutaneous injection (e.g. infiltration), topical, epidural, Intrathecal (injection into spinal canal)
Give examples of properties of ideal anaesthesia
stable in solution, (requires no additive), non-irritating to tissues, no permanent damage to nerves, no systemic toxicity, no allergic response, potent
effective topically and by infiltration, rapid onset of action, predictable duration
What are the names for the two general types of local anaesthetics?
Lignocaine and Procaine. Lignocaines use an amide as the intermediate chain and Procaines use an ester linkage
What are the two terminal groups in a local anaesthetic?
Lipophilic aromatic terminal and a hydrophilic amino terminal
What is the purpose of the aromatic terminal and what property allows this?
To be lipophilic to penetrate fatty tissue such as the lipid nerve sheath to gain access to the nerve cell membrane to reach its site of action - unpolarised
What is the purpose of the amino terminal and what property allows this?
amino group allows charge for solubility in water so it can be dissolved in a solvent to inject it and to move through the interstitial fluid after injection
Give 4 examples of ester linked agents
Benzocaine, Procaine, Chloroprocaine and Tetracaine
Give 4 examples of amide linked agents
Lidocaine, Mepivocaine, Ropivaciaine, Bupivacaine, articaine
Describe the mechanism of action
The receptor for the voltage-gated Na+ channel isn’t accessible from the outside of the cell so the non-polar molecule diffuses through, then ionises and binds
Local anaesthetics bind most readily when the Na+ channel is in what state?
Inactivated
Which subunit of a Na+ channel does a L.A bind to?
IV
What is the order of sensitivity to L.A?
autonomic > warm > pain > pressure
True or False: rapidly firing axons will cause a lower amount of anaesthetic binding at a given concentration
False, it will be higher as the more firing means more opening which leads to more inactivated states which allows for more binding
What is the affect of acidosis on L.A
[When arterial pH is <7.35] Reduces the action as it will cause more ionisation of molecule meaning it cannot diffuse through nerve membrane
What is a tonic v.s phasic blockade
Tonic- with pig gaps between impulses, it returns to equilibrium after each impulse so no stacking of blockages
Phasic - short gaps between impulses causes ‘stacking’ of bound channels
What 2 main types of topical anaesthesia used?
Benzocaine (bubblegum, good with kids) and Xylanor gel
What do you need to always check on a local anaesthetic cartridge before use?
Name, concentration, expiry date, serial number, solution
What local anaesthetic has both an amide and ester link?
Articaine
What anaesthetic is more effective when used plain as opposed to lidocaine?
Priolcaine 4% (also called citanest)
What local anaesthetic has a slow onset but long duration?
Bupivacaine
True or false: you can rely on the patient to describe how much they drink.
True, but actually never trust what they say
Which anaesthetic should be avoided for pregnant women and why?
Anything with Felypressin, as it is similar in structure to oxytocin and so is theoretically possible to kick start labour
Describe the possible effects of a needlestick on the patient.
Soft tissue trauma, nerve trauma, intravascular injection that can lead to cardiac arrest and attack on the liver
List the reasons for a failure of a L.A
Insufficient solution injected, inaccurate placement, someone’s anatomical differences, some teeth are harder than other, outdated L.A, infection/inflammation, pH in the mouth, intravascular injection
In the event of a latex allergy, which anaesthetics have a rubber-free bung and so can be used?
Citanest (prilocaine) with octapressin
What is one thing you can do to avoid psychogenic reactions?
Don’t wave the needle around, prepare and move it below the patient or out of sight
What to do during a vasovagul attack? (faint)
Lie the patient flat down, loosen tight clothing, call for help, check airway, 02 if needed, assume more complicated if they are not recovered in 2-3 minutes
What can you give to someone with heart complications?
Felypressin as opposed to adrenaline as it puts less stress on the heart
What can happen if you inject the muscles of mastication?/
Trismus (lockjaw)
What instruction should be given to patient at the injection?
DONT SAY SHARP SCRATCH
focus them on breathing, ‘dont think about your right thumb’, explain using very neutral phasing
