Pharmacology

Question 1

define volume of distribution

Answer 1

D (total drug in body (mg)) divided by c (plasma concentration (mg/L)) unit would be litres.

Question 2

Pharmacodynamics

Answer 2

What the drug does to the body. relates to the study of a drugs effect and mechanism within the body

Question 3

what is a “therapeutic dose”

Answer 3

the amount/dose of drug required to produce desired change in their disease or condition.

Question 4

describe the mode of action “absorption/administration”

Answer 4

absorption= the movement of the drug from the site of administration to the blood stream. (Passive absorption, facilitated absorption, active transport, pinocytosis)

Question 5

define tachyphylaxis

Answer 5

an acute, rapid, sudden, decrease in response to a drug after its administration, rendering it less effective.

Question 6

define “half life”

Answer 6

is the time it takes the body to reduce the amount of drug in the plasma by half.

Question 7

intropes

Answer 7

Inotropes increase the contractility of the heart.

Inotropes increase CO, thereby increasing MAP and maintaining perfusion to vital organs and tissues. Inotropes increase CO by increasing both SV and HR.

noradrenaline
adrenaline
ephedrine

Question 8

describe the mode of action “metabolism”

Answer 8

metabolism= the process of transformation of the drug within the body to take it from being lipophilic to more hydrophilic so that it can be excreted from the body by the kidneys.

Question 9

spinals related to cardiac effects

Answer 9

blocks the nerves in the thoraco-lumbar region (sympathetic) resulting in blocking sympathetic reflexes and parasympathetic takes over decreasing the blood pressure.

(total spinal= respiratory muscle paralysis, respiratory depression, apneic, cardiac arrest).

management of total spinal= intubation/establish patent airway, why? Because of total spinal affecting respiratory muscle function and subsequent loss of spontaneous breathing

Question 10

propofol

Answer 10

Painful on injection, decreases cardiovascular system, respiratory depressant, alters EEG monitoring (epileptic movement), short acting, induction and sedation agent. • CNS
o Excitatory movement upon induction
o Euphoria at low doses -> abuse potential
CVS
o Decreases BP
o Blunts baroreceptor reflexes
Resp
o Resp depression
o Blunted response to hypercarbia & hypoxia
o Hiccups
Anaphylaxis
Pain on injection- pH difference with blood
Propofol infusion syndrome- form of metabolic acidosis
Bacterial contamination

doses= 1.5-2.5mg/kg for induction. 20ml/200mg ampules.
1-1.5 mg/kg/min

pharmacokinetics = (ADME) IV adminitration. Works on GABA receptors. metabolised in the liver. excreted by kidneys in urine.

Question 11

intralipid

Answer 11

bolus of 1.5mls/kg over 1 minute
Infusion of 15ml/kg/hr
IF CVS IS STILL UNSTABLE= repeat boluses unto 3 in total and 5 mins between and double infusion rate.
Do not exceed 12ml/kg
The theory states that highly lipid-soluble drugs, including local anaesthetics and non-local anaesthetic drugs, are absorbed into the lipid emulsion of the plasma and removed from tissues affected by toxicity. reversing cardiotoxic effects of local anaesthetics.

Question 12

describe the parasympathetic nervous system

Answer 12

the parasympathetic nervous system refers to our “rest and digest” involuntary reflexes such as vasodilation, devrease in heart rate and contractility, constriction of bronchioles and constriction of pupils. the nerve fibers come from the cranial-sacral region and have longer per-ganglionic fibres and shorter post-ganglionic fibres. acetylcholine is the neurotransmitter released at both junctions. the pre-ganglionic junction is a nicotinic receptor and the post-ganglionic fibre is a muscarinic receptor (cholinergic).

Question 13

adrenaline

Answer 13

a potent alpha and beta agonist. comes in amplues of either 1:1000 (1ml) or 1:10000 (10ml) and both contain 1 mg.
bolus dose for anaphylaxis in 100mcg (1 ml of 1:10,000).
bolus dose for cardiac arrest is 1mg.

Question 14

atropine

Answer 14

increases heart rate.
Anti muscurinic, anti cholinergic antagonist that blocks the receptors of the parasympathetic fibres allowing the sympathetic system to take over and increase heart rate. Drys secretions (mouth) and blurred vision. Dose = 20mcg/kg bolus. 600mcg or 0.6mg in an ampule of 1ml

Question 15

olol’s

Answer 15

labetalol = alpha and beta blocker
metopralol = beta blocker
esmalol = beta blocker

Question 16

ketamine

Answer 16

induction agent. non-respiratory depressant and hardly any effect on the cardiovascular system. Increases intra cranial and ocular pressure. Analgesic agent. Hallucinations. Induction agent shocked patients (very low BP, hypovalemic). PCAs. Doses = 1mg/kg. IV (induction dose) 10-20mg/kg.

Question 17

define “bio availability”

Answer 17

is the percentage of drug that is a absorbed

Question 18

describe the sympathetic nervous system

Answer 18

the sympathetic nervous system refers to our “fight or flight” involuntary reflexes such as vasoconstriction (alpha 1), increased heart rate and contractility (beta 1), dilatation on bronchioles (beta 2) and dilation of pupils. the nerve fibres come from the thoraco-lumbar region and have shorter pre-ganglionic fibres and longer post-ganglionic fibres. noradrenaline is the neurotransmitter released at the post ganglionic junction to stimulate the alpha and beta receptors (adrenergic). acetylcholine is released and the pre-ganglionic junction and is considered nicotinic.

Question 19

describe the mode of action “distribution”

Answer 19

distribution= the movement of drugs within the body

Question 20

Paracetamol

Answer 20

Paracetamol= analgesic and Anti pyretic. Weak anti inflammatory effect. inhibitor of the synthesis of prostaglandins. Side effects= paracetamol-induced liver intoxication from large doses. 15mg/kg 4-6 times a day

Question 21

volitile

Answer 21

Volatile anaesthetics exert their effects at multiple sites throughout the central nervous system.

It appears that volatile agents preferentially increase power of GABAA receptors and two-pore domain K+ channels

Question 22

midazolam

Answer 22

(benzodiazapam works at the gaba receptor). Comes in 5 mg/5 ml ampule. 1-2 mg IV bolus for sedation and amnesia. Oral = 0.5mg/kg. CNS depression and addiction from long term use.
reversed by flumazenal

Question 23

side effects vs adverse effects

Answer 23

Side effects= drug effect other than the therapeutic effect that is usually undesirable but not harmful.

Adverse effects – including allergic reactions= undesirable and potentially harmful drug effect other than the therapeutic effect.

Question 24

amiodarone

Answer 24

anti-arrhythmic. acts on the nodal cells in the myocardium to regulate fast rhythms and has little effect on the BP.

Question 25

suxamethonium

Answer 25

is a depolarising neuromuscular blockade and aggressive nicotinic agonist that works by attaching to the nicotinic receptor at the neuromuscular junction to create the depolarisation of the nerve (sodium channels open) causing the “twitching” of muscles, and then remains on the receptor and blocking it rendering it unable to receive acetylcholine for depolarisation and therefore causing neuromuscular blockade (muscle relaxation).
dose= 100mg/2ml ampules. 1-1.5 mg/kg intubation dose for adults. 1ml from the ampule (50mg) dilutes into 5ml makes 10mg/ml.

side effects = bradycardia, increased intracranial pressure, increased intraoccular pressure, rise in potassium esp. in patients with burns, crush injury, trauma, renal failure, MH trigger, high reaction rate, sux apneoa, muscle aches and pains

Question 26

Dantrolene

Answer 26

acts within skeletal muscle by acting as a receptor antagonist to the ryanodine receptor, to depress calcium ion release which reduces excitation-contraction coupling in skeletal muscle.

Question 27

non-depolarising Muscle relaxants

Answer 27

Rocuronium = .5 - 1 mg per kg for intubating dose. 50mg or above for RSI dose competitive non depolarising. At neuromuscular site, ACh normally produces electrical depolarization of the postjunctional membrane of motor end-plate, which leads to conduction of muscle action potential and subsequently induces skeletal muscle contraction. Rocuronium acts by competing for cholinergic receptors at the motor end-plate. Rocuronium acts by competitively binding to nicotinic cholinergic receptors. The binding of vecuronium decreases the opportunity for acetylcholine to bind to the nicotinic receptor at the postjunctional membrane. As a result, depolarization is prevented, calcium ions are not released and muscle contraction does not occur.

Question 28

meteraminol

Answer 28

potent alpha agonist

Question 29

salbutamol

Answer 29

selective beta 2 agonist. You still get tachycardia because its not pure (stimulates both beta 1 and 2). beta 2 dilates the brocheoles and beta 1 increased heart rate and contractility.

Question 30

neostigmine

Answer 30

anticholinesterase (prevents break down of acetylcholine (neuro transmitter). used to reverse muscle paralysis from non-depolarising muscle relaxant. inhibits the break down of acetylcholine at both the neuromuscular junction and the parasympathetic pathway resulting in bradycardia. often given with atropine, a anticholinergic and antimuscarinic antagonist which blocks the cholinergic receptors and allows the sympathetic pathway to increase the heart rate.

Question 31

define “first pass metabolism”

Answer 31

it is drug metabolism that occurs in the intestines and liver during oral absorption of drugs into the systemic circulation.

Question 32

antibiotics

Answer 32

Antibiotics fight bacterial infections either by killing bacteria or slowing and suspending its growth. They do this by: attacking the wall or coating surrounding bacteria. high anaphylaxis rate.

Question 33

ephidrine

Answer 33

alpha and beta agonist. comes in 30mg/1ml. diliuted into 10mls saline and bolus of 1mL increments= 3mg/1mL bolus

Question 34

define toxicity

Answer 34

refers to how harmful or poisonous a drug can be to a person. Drug toxicity occurs when the drug dose is too high or if the liver and/or kidneys fail to excrete the drug.

Question 35

phenylephrine

Answer 35

alpha agonist

Question 36

Opioids

Answer 36

pin point pupils, constipation, resp depression, disorientation, itching (intrathecal morphine), tolerance, urinary retention, risk of addiction, sedation, hallucinations, neausea and vomiting. works on the mew receptors.

Tramadol= acts on mu opioid receptor, blocking the neuron from communicating pain to the brain. Side effects= constipation, nausea and vomiting, respectively depression. You may have increased levels of serotonin (a hormone in your body). This can cause a condition called serotonin syndrome

Question 37

Pharmacokinetics

Answer 37

relates to the study of how a drug moves within the body commonly relating to the terms absorption/administration, distribution, metabolism and elimination (ADME)

Question 38

define multimodal

Answer 38

decrease the narcotic side effects by using multiple different pain relief to lessen the dose or narcotics.

Question 39

Local anaesthetics

Answer 39

Local anaesthetics = Local anaesthetics act by preventing the generation and transmission of impulses along nerve fibres and at nerve endings; depolarisation and ion exchange are inhibited. This is achieved by anesthetics reversibly binding to and inactivating sodium channels. Sodium influx through these channels is necessary for the depolarization of nerve cell membranes. When a nerve loses depolarization and capacity to propagate an impulse, the individual loses sensation in the area supplied by the nerve. Testing indicates that ropivacaine is comparable to (or slightly more potent than) bupivacaine in blocking sensory fibres and less active in blocking motor fibres (less on heart).

Lignocaine is short acting. With adrenaline 5-7mg/kg. Without = 3mg/kg
Ropivocaine is longer acting. 2.5 mg/kg
Bupivicaine longer acting

Question 40

define tolerance

Answer 40

the ability of the body to alter its response to drug affects so that the effects are minimised over time.

Question 41

describe the mode of action “elimination”

Answer 41

elimination= the removal of drugs from the body

Question 42

describe the central nervous system and peripheral nervous system

Answer 42

CNS contains the brain and the spinal cord and the PNS contains the cranial and spinal nerves and is the communication lines from the CNS to the body. the PNS is broken down into sensory (afferent) and motor (efferent) systems. The motor (efferent) pathway then gets broken down into autonomic (involuntary) and somatic (voluntary). the autonomic system then gets further divided into the sympathetic nervous system and the parasympathetic nervous system.