Drugs - Pharmacology, Metabolism, Special Notes and Pharmacokinetics Flashcards
1 - 3 Mild Pain Analgesic Requirements
May not require analgesia
Consider non pharmacological approaches
Consider non opiod analgesia - paracetamol, ibuprofen
4 - 6 Moderate Pain Analgesic Requirements
Consider:
mild pain analgesic steps
non opioid analgesia - Paracetamol, ibuprofen
7 - 10 Severe Pain Analgesic Requirements
Consider mild and moderate treatment steps
Will require NAS, IM, IV analgesia - Penthrane, fentanyl, morphine
Adrenaline Metabolism
Metabolised by sympathetic nerve endings and subject to mitochondrial enzymatic breakdown by monoamine oxidase at the synaptic level
Adrenaline pharmacology in asthma
sympathomimetic agent that is an alpha and beta adrenergic receptor antagonist that makes the heart beat faster and harder due to alpha 1 causing peripheral vasoconstriction and beta 1 increasing ventricular irritability, contractile force, conductivity and AV node. Beta 2 stabilises mast cells to negate their deregulatory effect
Adrenaline pharmacology in anaphylaxis
sympathomimetic agent which is an alpha and beta adrenergic receptor antagonist that makes the heart beat faster and harder due to alpha 1 causing peripheral vasoconstriction and beta 1 increasing ventricular irritability, contractile force, conductivity and AV node. Beta 2 stabilises mast cells to negate their deregulatory effect
Adrenaline pharmacology in cardiac arrest
sympathomimetic agent which is an alpha and beta adrenergic receptor antagonist that makes the heart beat faster and harder due to alpha 1 causing peripheral vasoconstriction and beta 1 increasing ventricular irritability, contractile force, conductivity and AV node. Beta 2 stabilises mast cells to negate their deregulatory effect
Adrenaline pharmacology in croup
reduces bronchial and tracheal epithelial permeability decreasing airway oedema, increasing airway radius and improving airflow.
It improves Westley Croup Scores at 30 minutes.
Adrenaline Special Notes
1: 1,000 (1 mg/mL) adrenaline (epinephrine) presentation should be used for all nebuliser administration
1: 10,000 (100 microg/1 mL ) or a 1 : 100,000 (10 microg/1 mL ) adrenaline (epinephrine) preparation should be used for all low dose IM/IV injections
Aspirin Metabolism
converted to salicyclic acid primarily in the GI mucosea and liver
excreted by the kidneys
Aspirin Pharmacology
prevents platelets from aggregating to exposed collagen fibres at the site of vascular injury
Aspirin Special Notes
Patients with suspected ACS or acute pulmonary oedema who have had less than 300 mg aspirin in the previous 24 hours should be administered a dose of aspirin that equates to a total daily dose of 300–450 mg
Ceftriaxone Metabolism
Excreted as a variety of active and inactive metabolites through urine, bile and faeces
Ceftriaxone Pharmacology
A third generation cephalosporin antibiotic with a bactericidal action
Ceftriaxone Special Notes
Due to adverse affects associate with IM administration, IV administration is preferred
Rapid administration of large doses may result in seizures due to high sodium content
All cannula and IV lines must be flushed thoroughly with sodium chloride 0.9% following each administration
Prepared in aseptic manner
Dexamethasone Metabolism
metabolised by the liver and excreted by the kidneys
Dexamethasone Pharmacology
Long-acting synthetic corticosteroid that produces anti-inflammatory and immunosuppressive effects
Presumed effect is vasoconstrictive actions in the upper airway, followed by systemic antiinflammatory effect
Dexamethasone Special Notes
the preferred corticosteroid for the treatment of croup due to its lower hospital re-presentation rate
All patients administered dexamethasone for the treatment of croup must be transported to an appropriate health facility for assessment
The Westley Croup Score must be used by all officers to assess croup severity
Administer with syringe or clean spoon
Mix with small amount of sweet ingestible liquid
Fentanyl Metabolism
metabolised by the liver, excreted by the kidneys
Fentanyl Pharmacology
synthetic narcotic analgesic that acts on the central nervous system by binding with the opioid receptors
Fentanyl Special Notes
When combined narcotic (morphine and fentanyl) therapy is administered, the total max dose must be calculated using a combination of all morphine and MME (eg fentanyl) medication
Hypotensive adult Pts (SBP 90 mmHg) all incremental fentanyl doses must be no greater than 25 microg for IV and 50 microg for IM
CCP backup required in fentanyl administration to hypotensive pts
Glucagon Metabolism
Metabolised by the liver, kidneys and in the plasma
Glucagon Pharmacology
Hyperglycaemic agent that mobilises hepatic glycogen which is released into the blood as glucose with inotropic and chronotropic effects not mediated through beta-receptors
Glucagon Special Notes
Oral carbs should be given when the Pt has responded to glucagon to restore liver glycogen and prevent secondary hypoglycaemia
low threshold for glucagon administration in hypotensive/shocked anaphylaxis Pts when presenting with heart failure and/or prescribed beta blocker therapy
Prepare in aseptic manner, disinfect rubber stopper of vial with antimicrobial swab and allow to dry before piercing
Glucose 10% Metabolism
Broken down in most tissues and distributed throughout total body water
Glucose 10% Pharmacology
A sugar that is the principal energy source for body cells, especially the brain
Glucose 10% Special Notes
the preferred treatment for hypoglycaemia for patients unable to take oral glucose due to its rapid onset and ability to quickly restore blood glucose concentration to normal values
Glucose Gel Metabolism
Broken down in most tissues and distributed throughout total body water
Glucose Gel Pharmacology
Quickly absorbed in the intestinal tract - principal energy source for body cells, especially the brain.
Glyceryl trinitrate (GTN) Metabolism
readily absorbed and metabolised by the liver
Glyceryl trinitrate (GTN) Pharmacology
decreases preload and afterload, dilates blood vessels to allow blood through the coronary veins and arteries and pools blood in peripheral veins
Glyceryl Trinitrate (GTN) Special Notes
Subling GTN first line Tx for ACS, however IV GTN should be considered as part of the mgmt regime for all Pts unresponsive to subling GTN, narcotics and/or blockers
GTN is first line Tx for autonomic dysreflexia, however morphine should be considered as part of the mgmt regime if Pt unresponsive to initial Tx
Hydrocortisone Metabolism
Metabolised by the liver, excreted by the kidneys
Hydrocortisone Pharmacology
Inhibit the inflammatory action of the phospholipase A2 enzyme and used for multiple reasons for infections in a variety of setting for long term disease processes
Hydrocortisone Special Notes
Each 100 mg hydrocortisone vial is to be reconstituted with 2 mL sodium chloride 0.9% or water for injection
All canulae and IV lines must be flushed thoroughly with sodium chloride 0.9% following each medication administration
Prepare in aseptic manner, disinfect rubber stopper with antimicrobial swab and allow to dry before piercing
Ibuprofen metabolism
Metabolised by the liver and exreted mainly by the kidneys
Ibuprofen pharmacology
Non-selective NSAID that inhibits the synthesis of prostaglandins resulting in analgesic, antipyretic and anti-inflammatory actions
Ibuprofen Special Notes
Consider previous doses by the Pt, carer, parent or guardian
Administer with or shortly following food/milk
Can be used in conjunction with paracetamol for additional pain relief
Ipratropium bromide Metabolism
metabolised by the liver and excreted by the kidneys
Ipratropium bromide Pharmacology
Antimuscurinic agent that promotes bronchodilation by inhibiting cholinergic bronchomotor tone
Ipratropium bromide Special Notes
Must be administered in conjunction with salbutamol - solutions may be mixed and administered via the same nebuliser mask
Loratadine Metabolism
absorbed in the GI tract with rapid first-pass hepatic metabolism
Loratadine Pharmacology
long acting, second generation peripheral histamine H1 receptor antagonist
Loratadine Special Notes
Antihistamines have no role in the Tx or prevention of respiratory or cardiovascular symptoms in anaphylaxis
May be administered with or without food
Methoxyflurane metabolism
Metabolised by the liver and excreted mainly by the lungs
Methoxyflurane pharmacology
More susceptible to metabolism than other halogenated ethers and has a greater propensity to diffuse into fatty tissue
Methoxyflurane Special Notes
At no time should unconsciousness be deliberately induced using methoxyflurane
The lowest dose of methoxyflurane to provide analgesia should be used
Pt not to be left unattended
If the Pt prefers simultaneous inhalation through both nose and mouth, the inhaler may be connected into a standard anaesthetic face mask prior to administration
Only one dose of 3 mL should be administered per Pt whilst in the ambulance
No single officer should administer more than 2 doses in the ambulance per shift
Where possible, ambulance should be adequately ventilated
Midazolam Metabolism
Metabolised by the liver, excreted by the kidneys
Midazolam Pharmacology
Short acting CNS depressant that enhances the action of the inhibitory neurotransmitter GABA, inducing amnesia, anaesthesia, hypnosis and sedation
Midazolam Special Notes
Focal seizure activity in an unconscious or altered (GCS_<_12) treated as a generalised seizure - GCS >12 contact QAS Clinical Consultation and Advice Line
Take into account previous doses prior to arrival of midazolam or diazepam
Contact QAS Clinical Consltation and Advice Line if not responding to QAS initiated Tx
First dose of midazolam for seizures must be administered NAS or IM injection unless IV cannula already in situ
All IV doses must be diluted with sodium chloride 0.9% to make 5 mg midazolam in 5 mL presentation
Morphine Metabolism
Metablised by the liver, kidneys and lungs
Morphine Pharmacology
Narcotic analgesic that acts on CNS by binding with opioid receptors altering pain perception processes and emotional response to pain. Causes respiratory depression, vasodilation, decreases gag reflex and slows AV node conduction.
Morphine Special Notes
When combined narcotic (orphine and fentanyl) therapy is administered, the total maximum dose is to be calculated using a combination of all morphine and morphine milligram equivalent (MME) medication (eg fentanyl), eg 10 mg morphine and 100 microg fentanyl would equl the ACP total max dose of 20 mg MME
When administered to hypotensive Pt, ACPs must call for CCP backup where available
Hypotensive adult Pts (SBP < 90 mmHg), all incremental morphine doses are to be no greater than 2.5 mg IV or 5 mg IM
Single IM dose morphine is suitable anagesic for moderate to severe labour pain in full term mothers. Advise receiving hospital of dose.
Ondansetron Special Notes
ampoules should be protected from light
IV cannula not to be inserted for ondansetron administration only
transient adverse effects have been reported with rapid IV injections
Ondonsetron Metabolism
metabolised by the liver and excreted by the kidneys
Ondonsetron Pharmacology
Serotonin 5-HT3 antagonist which inhibits the vagus nerve and blocks serotonin receptors in the chemoreceptor trigger zone
Oxygen Metabolism
N/A
Oxygen Pharmacology
A colourless, odourless gas essential for the production of cellular energy
Oxygen Special Notes
Diving accidents are not covered by this DTP - administer high flow oxygen
Sat monitors unable to differentiate between carboxyhaemoglobin and oxyhaemoglobin, therefore carbon monoxide poising Pts must be administered the maximum oxygen dose irrespective of SpO2 readings
COPD Pts must have a rate of 6 L/min - all other Pts at 8 L/min
FiO2 levels influenced by delivery systems, rep rate and open or closed mouth
Oxytocin Metabolism
metabolised by the liver and excreted by the kidneys
Oxytocin Pharmacology
Stimulates uterine contractions by altering calcium concentrations within the uterine muscle cells increasing it tonicity
Oxytocin Special Notes
Oxytocin is only to be administered to the consenting patient - women who prefer a physiological management must birth the placenta unaided, by maternal effort and the natural force of gravity
to allow for the benefits of delayed cord clamping it is acceptable to do a modified active third stage management by waiting until the cord has stopped pulsating to administer oxytocin. This is particularly important in neonatal resuscitation where the baby is resuscitated between the mum’s legs to receive the benefit of a pulsing cord and placental perfusion.
Paracetamol Metabolism
Metabolised by the liver, excreted by the kidneys
Paracetamol pharmacology
A p-aminophenol derivative that exhibits analgesic and antipyretic activity. It does not possess significant anti-inflammatory activity
Paracetamol Special Notes
Consider previous doses administered
May be administered with or without food
Salbutamol Metabolism
metabolised by the liver, excreted by the kidneys
Salbutamol Pharmacology
Acts on B2 adrenoreceptors causing bronchodilation, inotropic and chronotropic actions. It stimulates the sodium/potassium ATPase pump, increasing intracellular K+ and reducing serum K+.
inotropic = heart contractility chronotropic = increased HR
Salbutamol Special Notes
When clinically appropriate, MDI is preferred to minisise aerosol generation, especially if infectious
Different preparation for IM and IV - using the incorrect one will cause serious adverse effects
COPD Pts received NEB salbutamol at 6 L/min, all other Pts at 8 L/min
Nebulised salbutamol will reduce serum potassium by 0.5 - 1 mmol/L within 30 minutes
Nebules to be stored within foil packet and discarded three months after opening - write date on packet when opened
Sodium chloride 0.9% metabolism
100% bioavailability. Excess sodium is predominantly excreted by the kidneys.
Sodium chloride 0.9% pharmacology
Electrolyte replenisher for maintenance or replacement of fluid and a vehicle for parenteral drug administration
Sodium Chloride 0.9% Special Notes
Use of volume expansion in uncontrolled haemorrhage (without concurrent TBI) may be associated with poor outcomes - only administer the minimum amount of IV/IO fluid to maintain a radial pulse
Hypotension with a concurrent TBI is associated with poor outcomes - only administer the minimum amount of IV fluid required to maintain a systolic BP 100 - 120mmHg (adult)
Excessive fluid infusion may lead to neurogenic pulmonary oedema in the spinal cord injured patient
Too rapid infusion of fluids in a patient without fluid deficit, or with underlying cardiac problems, may cause pulmonary oedema and congestive heart failure
A gentle fluid challenge may be considered for patients with suspected right ventricular infarct (following 12-Lead ECG acquisition with V4R) and no signs of left ventricular failure (e.g. pulmonary oedema)
BD PosiFlushSP pre-filled are for vascular devices only and NOT for any dry product reconstitution AND/OR medication dilution
Sucrose 24% Metabolism
mucosal absorption with hepatic metabolism
Sucrose 24% Pharmacology
increases endogenous opioids resulting in approximately 5−8 mins of analgesia in infants
Sucrose 24% Special Notes
Alternate support measures (e.g. breast feeding, appropriate positioning, distraction) should always precede oral sucrose administration
Oral sucrose is not considered appropriate for the management of continuing pain or distress
Oral sucrose to manage mpain should be used in conjunction with analgesics (eg paracetamol, NAS fentanyl)
Tranexamic Acid (TXA) Metabolism
metabolised by the liver, excreted by the kidneys
Tranexamic Acid (TXA) Pharmacology
Stops the conversion of plasminogen to plasmin, stopping the breakdown of fibrin and promoting clot strength, inhibiting lysis.
Water for injection metabolism
N/A
Water for injection pharmacology
Sterilised H2O
Water for Injection Special Notes
QAS medications approved for dilution with water for injection include: ceftriaxone, glucagon, hydrocortisone and ketamine
Water for injection may be used to assist with the administration of oral medication if required (aspirin, clopidogrel, paracetamol and ticagrelor)
Amiodarone Pharmacology
blocks Na+, K+, Ca++, alpha & beta channels prolonging action potential & refractory period, decreases excitability & improves potential for ROSC
Amiodarone Metabolism
Majority is excreted by the liver and GI tract in biliary excretion, may be some hepatic recirculation
Amiodarone Special Notes
- If the Pt is on oral amiodarone cardic arrest administration is authorised
- Pts with Torsade de Pointes due to suspected prolonged QT interval from excess amiodarone magnesium sulphate should be considered - contct QAS Clinical Consultation and Advice Line
What are the four main concepts of pharmacokinetics?
Absorption
Distribution
Metabolism
Excretion
What is drug absorption?
Route of administration
What is drug distribution?
Lipid solubility
Perfusion & transportation
What is drug metabolism?
Hepatic first-pass effect
Biotransformation
What is drug excretion?
Elimination & excretion
Factors affecting drug distribution
Lipid solubility
Plasma protein binding
Body composition
Tissue and organ perfusion
Organ function
How does lipid solubility affect drug distribution?
influences in which body compartments the drug may accumulate, directly affecting drug effect and dosage schedules
How does plasma protein binding affect drug distribution?
affects bioavailability and transportation of the drug
How does body composition affect drug distribution?
relative proportions and absolute amount of lean and adipose tissues
How does tissue and organ perfusion affect drug distribution?
impacts distribution of the drug throughout the body, and therefore effect, metabolism, and excretion
How does organ function affect drug distribution?
relates to those organ systems involved in the metabolism, elimination, and excretion of the drug
What is the primary drug distribution issue or paramedics?
tissue perfusion, and therefore cardiac function, blood pressure, and shock
What is the secondary drug distribution issue for paramedics?
functionality of kidneys and liver, for metabolism and excretion
Atropine Pharmacology
- Anticholinergic action inhibits vagus innervation of the heart
- loss of parasympatheic tone resulting in increased heart rate and contractility
Sodium bicarbonate Pharmacology
Provides extracellular sodium to overcome Na+ blockade
Reverses metabolic acidosis by reacting with H+ ions
Calcium gluconate Pharmacology
- Improves contractility
- Myocardial protection in hyperkalaemia
- Provides extracellular calcium to overcome Ca++ blockade
Magnesium sulphate Pharmacology
Stabilises the membrane in Torsades de Points by reducing Ca++ influx into the cell
Naloxone Pharmacology
opioid antagonist that prevents or reverses the effects of opioids including respiratory depression, sedation and hypotension. Naloxone antagonises the opioid effects by competing for the same receptor sites.
Naloxone Metabolism
hepatic
Naloxone Special Notes
- should only be administered following adequate patient oxygenation and ventilation
- should be administered cautiously to patients who are known or suspected to be physically dependent on narcotics
- not required in the vast majority of cases, and the patient will need only supportive therapy followed by transport
- duration of the narcotic may exceed that of naloxone and renarcotisation is possible
- Administration in the pre-hospital environment may unmask potentially unwanted side effects in the setting of poly pharmacy overdose
- should not be administered to the newly born, even in the setting of suspected or identified opiate exposure/overdose, as administration of naloxone may lead to acute withdrawal and seizures
Droperidol Pharmacology
Dopamine-2 receptor antagonist that increases brain turnover of dopamine; and
Mild alpha-adrenergic receptor blockade which can result in mild hypotension
Droperidol Metabolism
Hepatic metabolism with biliary/renal excretion as inactive metabolites
Droperidol Special Notes
Where a second dose of droperidol has been administered by an ACP2, a CCP must be requested and they may be cancelled if the second dose of droperidol achieves the desired sedation effect
Dosages and times of administration prior to QAS arrival must be considerd to ensure compliance with the QAS Droperidol DTP
In Lewy body dementia, antipsychotic (e.g. droperidol) can cause deterioration in cognitive and motor function, and may paradoxically increase agitation and worsen behaviour
For other presentations of dementia (e.g. Alzeheimer’s disease) droperidol is a suitable pharmacological agent for the management of acute behavioural disturbance
Under no circumstances is an IV cannula to be inserted for the sole purpose of droperidol administration. IV droperidol administration is only to occur when an IV cannula is already insitu
Magnesium Sulphate Pharmacology
It causes vasodilation and bronchodilation through inhibition of smooth muscle contraction. Magnesium ions also possess anticonvulsant and anti-dysrrhythmic properties
Magnesium Sulphate Metabolism
filtered in the kidneys and excreted predominantly in urine with small amounts in faeces and saliva
Box Jellyfish Antivenom Pharmacology
contains concentrated immunoglobulin that acts to neutralise the toxins present in the venom of the box jellyfish
Box Jellyfish Antivenom Metabolism
Hepatic and in muscle tissue
Box Jellyfish Antivenom Special Notes
- The dose of antivenom is related to the dose of venom, not based on the size of the patient
- At all times during antivenom therapy adrenaline (epinephrine)
- must be available in case of an anaphylactic reaction. If reaction
- occurs, immediately cease the administration of box jellyfish
- antivenom and treat patient in accordance with CPG: Anaphylaxis
- and allergy.
- IV injection is the preferred route of administration for all indications.
- If a patient is in cardiac arrest due to box jellyfish envenomation, the box jellyfish antivenom is only to be administered following the commencement of effective CPR, advanced life support measures and administration of cardioactive drugs
- Box jellyfish antivenom must be protected from light and stored between 2–8°C. DO NOT FREEZE
Hydroxocobalamin Pharmacology
(an injectable form of vitamin B12), binds with circulating and cellular cyanide to form cyanocobalamin, which is then excreted in urine
Hydroxocobalamin Metabolism
excreted by the kidneys
Hydroxocobalamin Special Notes
- Hydroxocobalamin infusions are only to be administered by appropriately trained QAS clinicians within the following response catchments:
- Central Queensland District: Orica Yarwun Cyanide Plant
- Darling Downs District: Texas Silver Mine
- North West District: Great Australian Mine, Lorena Gold Project
- Substantial increases in blood pressure may occur
- There are no adequate and well-controlled studies of hydroxocobalamin
- administration in pregnant women. Hydroxocobalamin should be used
- during pregnancy ONLY if the potential benefits justifies the potential
- risk to the fetus
Ketamine Pharmacology
a rapid acting dissociative anaesthetic agent that is primarily an NMDA receptor antagonist but also interacts with opioid, monoaminergic, muscarinic receptors and voltage sensitive Ca ion channels
Box Jellyfish Antivenom Pharmacology
contains concentrated immunoglobulin that acts to neutralise the box jellyfish toxins
Clopidogrel pharmacology
selectively inhibits the binding of adenosine diphosphate (ADP) to its platelet receptor, thereby inhibiting platelet aggregation
Clopidogrel metabolism
Hepatic metabolism with near equal amounts excreted in urine and faeces
Clopidogrel special notes
15–48% of patients have a poor platelet inhibition response
to clopidogrel. Therefore, the interventional cardiologist
may request the administration of ticagrelor
Enoxaparin pharmacology
Binds to antithrombin III and inhibits thrombin generation and factor Xa and thrombin
Enoxaparin metabolism
Hepatic but mostly eliminated unchanged
Enoxaparin special notes
IV administrations an enoxaparin 60 mg/0.6 mL graduated pre-filled syringe must be used. The air bubble MUST NOT be administered with the medication.
SUBCUT administrations an enoxaparin 100 mg/1 mL graduated pre-filled syringe must be used. The volume
to be injected (1 mg/kg) should be measured precisely using
the markings on the syringe. When adjusting to the correct
dose, hold the syringe with the needle tip pointing down.
Depress the plunger so the bottom of the air bubble is level
with the marking on the syringe that corresponds to the dose
required. The air bubble is required to be administered with
the medication.
What is the pharmacology of Sodium Bicarbonate?
hypertonic solution that reacts with excess hydrogen ions forming carbon dixoide and water, restoring plasma pH levels
What is the metabolism of Sodium Bicarbonate?
to C02 and H2)
What is the pharmacology of droperidol?
Antagonises dopamine receptors in the CNS
