Section 5.2: MICA Pharmacology Flashcards
Adenosine – Presentation/s
- 6mg in 2mL glass ampoule
Adenosine – Pharmacology
A naturally occurring purine nucleoside found in all body cells
Actions:
- Slows conduction through the A-V node, resulting in termination of re-entry circuit activity within or including the A-V nodal pathway
Adenosine – Metabolism
- By adenosine deaminase in red blood cells and vascular endothelium
Adenosine – Primary emergency indication/s
- AVNRT with adequate or inadequate perfusion but not deteriorating rapidly
- AVRT and associated Wolff-Parkinson-White (WPW) or other accessory tract SVT with adequate or inadequate perfusion but not deteriorating rapidly
Adenosine – Contraindication/s
- Second or third degree A-V block (may produce prolonged sinus arrest / A-V blockade)
- Atrial fibrillation
- Atrial flutter
- Ventricular tachy-arrhythmias
- Known hypersensitivity
Adenosine – Precaution/s
- Adenosine may provoke bronchospasm in the asthmatic Pt
- Adenosine is antagonized by methylxanthines (e.g. caffeine or theophyllines). The drug may not be effective in Pts with large caffeine intake or those on high doses of theophylline medication
Adenosine – Route/s of administration
- IV
Adenosine – Side effects
Usually brief and transitory:
- Transient arrhythmia (including asystole, bradycardia or ventricular ectopy) may be experienced following reversion
- Chest pain
- Dyspnoea
- Headache or dizziness
- Nausea
- Skin flushing
Adenosine – Special notes
- Adenosine has a very short half life. It should be administered through an IV as close to the heart as practicable, such as the cubital fossa
Adenosine – Onset, Peak & Duration times
IV effects:
- Onset: N/A
- Peak: N/A
- Duration: < 10 sec
Amiodarone – Presentation/s
- 150mg in 3mL glass ampoule
Amiodarone – Pharmacology
- Class III anti-arrhythmic agent
Amiodarone – Metabolism
- By the liver
Amiodarone – Primary emergency indication/s
- VF / pulseless VT refractory to cardioversion
- Sustained or recurrent VT
Amiodarone – Contraindication/s
- VF / pulseless VT refractory to cardioversion:
* Nil of significance in this indication
2. VT (conscious):
- Inadequate perfusion
- Pregnancy
3. Tri-cyclic Antidepressant (TCA) Overdose
Amiodarone – Precaution/s
- Following Fentanyl administration
Amiodarone – Route/s of administration
- IV
Amiodarone – Side effects
- Hypotension
- Bradycardia
Amiodarone – Special notes
- Amiodarone is incompatible with saline. Glucose 5% must be used as dilutant when preparing an IV infusion.
- An IV infusion of Amiodarone may be required during inter-hospital transfer. This will be prescribed by the referring physician and will normally be at a dose of 10 – 20mg / kg run over 24hrs.
Amiodarone – Onset, Peak & Duration times
IV effects (bolus):
- Onset: 2min
- Peak: 20min
- Duration: 2hr
Atropine – Presentation/s
- 0.6mg in 1mL polyamp
- 1.2mg in 1mL polyamp
Atropine – Pharmacology
An anti-cholinergic agent
Actions:
- Inhibits the actions of acetylcholine on post-ganglionic cholinergic nerves at the neuro-effector site, e.g. as a vagal blocker, and allows sympathetic effect to:
- Increase HR by increasing SA node firing rate
- Increase the conduction velocity through the A-V node
- Antidote to reverse the effects of cholinesterase inhibitors (e.g. organophosphate insecticides) at the post-ganglionic neuro-effector sites of cholinergic nerves to:
- Reduce the excessive salivary, sweat, GIT and bronchial secretions; and
- Relax smooth muscles
Atropine – Metabolism
- By the liver. Excreted mainly by the kidneys.
Atropine – Primary emergency indication/s
- Bradycardia with poor perfusion
- Organophosphate poisoning with excessive cholinergic effects
Atropine – Contraindication/s
- Officially, nil of significance in the above indications
- ? Known hypersensitivity to Atropine or its derivatives.
Atropine – Precaution/s
- Atrial flutter
- Atrial fibrillation
- Do not increase HR above 100bpm except in children under 6 years
- Glaucoma
Atropine – Route/s of administration
- IV
- ETT
Atropine – Side effects
- Tachycardia
- Palpitations
- Dry mouth
- Dilated pupils
- Visual blurring
- Retention of urine
- Confusion, restlessness (in large doses)
- Hot, dry skin (in large doses)
Atropine – Special notes
N/A
Atropine – Onset, Peak & Duration times
IV effects:
- Onset: < 2min
- Peak: < 5min
- Duration: 2 – 6hr
Dexamethasone – Presentation/s
- 8mg in 2mL glass vial
Dexamethasone – Pharmacology
A corticosteroid secreted by the adrenal cortex
Actions:
- Relieves inflammatory reactions
- Provides immunosuppression
Dexamethasone – Metabolism
- By the liver and other tissues. Excreted predominantly by the kidneys
Dexamethasone – Primary emergency indication/s
- Bronchospasm associated with acute respiratory distress not responsive to nebulised Salbutamol
- Anaphylaxis
- Acute exacerbation of COPD
Dexamethasone – Contraindication/s
- Known hypersensitivity
Dexamethasone – Precaution/s
- Solutions which are not clear or are contaminated should be discarded
Dexamethasone – Route/s of administration
- IV
- IM
Dexamethasone – Side effects
- Nil of significance in the above indication
Dexamethasone – Special notes
- Does not contain an antimicrobial agent, therefore use the solution immediately and discard any residue
Dexamethasone – Onset, Peak & Duration times
IV effects:
- Onset: 30 – 60min
- Peak: 2hr
- Duration: 36 – 72hr
Dextrose 5% – Presentation/s
- 100mL infusion soft pack
Dextrose 5% – Pharmacology
An isotonic crystalloid solution
Composition:
- Sugar – 5% dextrose
- Water
Actions:
- Provides a small source of energy
- Supplies body water
Dextrose 5% – Metabolism
Dextrose:
- Broken down in most tissues
- Stored in the liver and muscle as glycogen
Water:
- Distributed throughout total body water, mainly in the extracellular fluid compartment
- Excreted by the kidneys
Dextrose 5% – Primary emergency indication/s
- Vehicle for dilution and administration of IV emergency drugs
Dextrose 5% – Contraindication/s
- Nil of significance in the above indication
Dextrose 5% – Precaution/s
- Nil of significance in the above indication
Dextrose 5% – Route/s of administration
- IV infusion
Dextrose 5% – Side effects
- Nil of significance in the above indication
Dextrose 5% – Special notes
IV half life:
- Approximately 20 – 40min
Dextrose 5% – Onset, Peak & Duration times
- Onset: N/A
- Peak: N/A
- Duration: N/A
Enoxaparin (Clexane) – Presentation/s
- 100mg in 1mL pre-filled syringe with graduated markings (SC injection)
- 40mg in 0.4mL glass ampoule (IV bolus)
Enoxaparin (Clexane) – Pharmacology
- Binds to and accelerates the action of antithrombin III which inactivates clotting factors IIa (thrombin) and Xa, inhibiting the conversion of prothrombin to thrombin
Enoxaparin (Clexane) – Metabolism
- Metabolised by the liver
Enoxaparin (Clexane) – Primary emergency indication/s
- Acute STEMI
Enoxaparin (Clexane) – Contraindication/s
- Known allergy or hypersensitivity
- Active bleeding (eg peptic ulcer, intracranial haemorrhage)
- Bleeding disorders
- Severe hepatic impairment / disease
- Heparin-induced thrombocytopenia (HIT)
Enoxaparin (Clexane) – Precaution/s
- Renal impairment
- If Pt > or = 75yo, omit the initial IV bolus dose and only administer 0.75mg / kg SC injection with a maximum 75mg SC
Enoxaparin (Clexane) – Route/s of administration
- Enoxaparin 30mg IV followed 15min later by 1mg / kg SC not exceeding 100mg SC
Enoxaparin (Clexane) – Side effects
- Bleeding
- Bruising
- Pain at injection site
- Hyperkalaemia
- Mild reversible thrombocytopenia
Infrequent
- Transient elevation of liver aminotransferases
- Severe thrombocytopenia
Rare
- Skin necrosis at injection site
- Osteoporosis with long term use
- Allergic reactions including urticaria and anaphylaxis
- Hypersensitivity reactions
Enoxaparin (Clexane) – Special notes
- STEMI – 12 lead ECG shows ST elevation > or = 1mm in two contiguous limb leads (I, II, III, aVR, aVL, aVF) or ST elevation > or = 2mm in two contiguous chest leads (V1, V2, V3, V4, V5, V6), new LBBB
Enoxaparin (Clexane) – Onset, Peak & Duration times
- Onset: Within 3hrs
- Peak: 3 – 6hrs
- Duration: > or = 12hrs
Frusemide – Presentation/s
- 40mg in 4mL glass ampoule
Frusemide – Pharmacology
A diuretic
Actions:
- Causes venous dilatation and reduces venous return
- Promotes diuresis
Frusemide – Metabolism
- Excreted by the kidneys
Frusemide – Primary emergency indication/s
- Acute LVF with SOB and audible fine crackles (bases, mid-zones or full field)
Frusemide – Contraindication/s
- Nil of significance in the above indication
Frusemide – Precaution/s
- Hypotension
Frusemide – Route/s of administration
- IV
Frusemide – Side effects
- Hypotension
Frusemide – Special notes
- The effect of vasopressor drugs will often be reduced after Rx with Frusemide
Frusemide – Onset, Peak & Duration times
IV effects:
- Onset: 5min
- Peak: 20 – 60min
- Duration: 2 – 3hr
Ketamine – Presentation/s
- 200mg in 2mL vial
Ketamine – Pharmacology
A rapid acting dissociative anaesthetic agent (primarily an N-methyl-D-aspartate [NMDA] receptor antagonist)
Actions:
Produces a dissociative state characterised by:
- A trance-like state with eyes open but not responsive
- Nystagmus
- Profound analgesia
- Normal pharyngeal and laryngeal reflexes
- Normal or slightly enhanced skeletal muscle tone
- Occasionally a transient and minimal respiratory depression
Ketamine – Metabolism
- By the liver and excreted by the kidneys
Ketamine – Primary emergency indication/s
- Rapid sequence intubation
- Intubation facilitated by sedation
Ketamine – Contraindication/s
- Known hypersensitivity
- Severe hypertension (SBP > 180mmHg)
Ketamine – Precaution/s
- Any condition where significant elevation of BP would be hazardous:
- Hypertension
- CVA
- Recent AMI
- CCF
- If being administered for analgesia, inject slowly over 1/60 to minimize risk of respiratory depression and hypertension
Ketamine – Route/s of administration
- IV
- IO
Ketamine – Side effects
Cardiovascular:
- Increase BP and HR
CNS:
- Respiratory depression or apnoea
- Emergent reactions (nightmares, restlessness, vivid dreams, confusion, hallucinations, irrational behaviour)
- Enhanced skeletal tone
- Nausea and vomiting
Ocular:
- Diplopia and nystagmus with slight increase in intraocular pressure
Other:
- Local pain at injection site
- Lacrimation
- Salivation
Ketamine – Special notes
N/A
Ketamine – Onset, Peak & Duration times
IV / IO effects:
- Onset: 30sec
- Peak: 12 – 25min
- Duration: N/A
Lignocaine 1% (IO Administration) – Presentation/s
- 50mg in 5mL amp (1%)
Lignocaine 1% (IO Administration) – Pharmacology
A local anaesthetic agent
Actions:
- Prevents initiation and transmission of nerve impulses (local anaesthesia)
Lignocaine 1% (IO Administration) – Metabolism
- By the liver (90%)
- Excreted unchanged by the kidneys (10%)
Lignocaine 1% (IO Administration) – Primary emergency indication/s
- To reduce the pain of IO drug and fluid administration in the responsive Pt
Lignocaine 1% (IO Administration) – Contraindication/s
- Known hypersensitivity
Lignocaine 1% (IO Administration) – Precaution/s
- Hypotension and poor perfusion
- Chronic LVF
- Liver disease
Lignocaine 1% (IO Administration) – Route/s of administration
- IO
Lignocaine 1% (IO Administration) – Side effects
CNS effects (common):
- Drowsiness
- Disorientation
- Decreased hearing
- Blurred vision
- Change or slurring of speech
- Twitching and agitation
- Convulsions
Cardiovascular effects (uncommon):
- Hypotension
- Bradycardia
- Sinus arrest
- AV block
Respiratory effects (uncommon):
- Difficulty in breathing
- Respiratory arrest
Lignocaine 1% (IO Administration) – Special notes
N/A
Lignocaine 1% (IO Administration) – Onset, Peak & Duration times
IO effects:
- Onset: 1 – 4min
- Peak: 5 – 10min
- Duration: 20min
Oxytocin – Presentation/s
- 10 units (IU) in 1mL glass ampoule
Oxytocin – Pharmacology
A synthetic oxytocic
Action:
- Stimulates smooth muscle of the uterus producing contractions
Oxytocin – Metabolism
- By the liver; excreted by the kidneys
Oxytocin – Primary emergency indication/s
- PPPH
Oxytocin – Contraindication/s
- Previous hypersensitivity
- Severe toxaemia (pre-eclampsia)
- Cord prolapse
- Exclude multiple pregnancy before drug administration
Oxytocin – Precaution/s
- If given IV may cause transient hypotension
- Concurrent use with Methoxyflurane may cause hypotension
Oxytocin – Route/s of administration
- IM
Oxytocin – Side effects
Uncommon via IM route:
- Tachycardia
- Bradycardia
- Nausea
Oxytocin – Special notes
Concomitant use with prostaglandins (Misoprostol) may potentiate uterotonic effect
Must be stored between 2 – 8 °C
Oxytocin – Onset, Peak & Duration times
IM effects:
- Onset: 2 – 4 min
- Peak: N/A
- Duration: 30 – 60min
Pancuronium – Presentation/s
- 4mg in 2mL polyamp
Pancuronium – Pharmacology
A non-depolarising neuromuscular blocking agent
Actions:
- Blocks transmission of impulses at the neuromuscular junction of striated muscles resulting in skeletal muscle paralysis
- Due to weak vagolytic action, a slight rise in HR and mean arterial pressure may be expected
Pancuronium – Metabolism
- By the kidneys; excreted mainly unchanged in the urine
Pancuronium – Primary emergency indication/s
- To maintain skeletal muscle paralysis and allow mechanical ventilation in intubated Pts following IFS, RSI or during inter-hospital transfer of ventilated Pts.
Pancuronium – Contraindication/s
- Pancuronium must not be given if continuous monitoring of Pt vital signs, including pulse oximetry and EtCO2 monitoring, is not available.
- Status epilepticus
Pancuronium – Precaution/s
- Ensure patency of IV access
- Sedatives must always be administered prior to Pancuronium
- ETT placement, adequacy of ventilation, Sp02, EtCO2, HR and BP must be continuously monitored
- Pts with myasthenia gravis should be given much smaller doses and monitored carefully due to the potential of increased degree of neuromuscular block
- Care should be exercised in Pts with renal impairment
Pancuronium – Route/s of administration
- IV
- IO
Pancuronium – Side effects
- Slight increase in HR
- Slight increase in mean arterial pressure
- Localised reaction at injection site (rare)
Pancuronium – Special notes
- Allergic reactions such as urticaria, laryngeal oedema, bronchospasm and anaphylactic shock have been reported.
- Pancuronium infusions required during inter-hospital transfers are to be prescribed and signed by the referring hospital medical officer. The initial dose is usually 0.1mg / kg.
Pancuronium – Onset, Peak & Duration times
IV effects:
- Onset: 2 – 3min
- Peak: 8 – 10min
- Duration: 35 – 45min
Sodium Bicarbonate 8.4% – Presentation/s
- 50mL prepared syringe
- 100mL glass bottle
Sodium Bicarbonate 8.4% – Pharmacology
A hypertonic crystalloid solution
Composition:
- Contains sodium and bicarbonate ions in a solution of high pH
Action:
- Raises pH
Sodium Bicarbonate 8.4% – Metabolism
- Sodium: Excreted by the kidneys
- Bicarbonate: Excreted by the kidneys as bicarbonate ion and by the lungs as CO2
Sodium Bicarbonate 8.4% – Primary emergency indication/s
- Cardiac arrest, after 15min of AV CPR
- Symptomatic TCA OD
Sodium Bicarbonate 8.4% – Contraindication/s
- Hypothermia < 30°C
Sodium Bicarbonate 8.4% – Precaution/s
- Administration of Sodium Bicarbonate 8.4% must be accompanied by effective ventilation and ECC if required
- Since Sodium Bicarbonate 8.4% causes tissue necrosis, care must be taken to avoid leakage of the drug into the tissues
- Because of the high pH of this solution, do not mix or flush any other drug or solution with Sodium Bicarbonate 8.4%
Sodium Bicarbonate 8.4% – Route/s of administration
- IV
Sodium Bicarbonate 8.4% – Side effects
- Sodium overload may provoke pulmonary oedema
- Excessive doses of Sodium Bicarbonate 8.4%, especially without adequate ventilation and circulation, may cause an intracellular acidosis
Sodium Bicarbonate 8.4% – Special notes
N/A
Sodium Bicarbonate 8.4% – Onset, Peak & Duration times
IV effects:
- Onset: 1 – 2min
- Peak: N/A
- Duration: Depends on cause and Pt’s perfusion
Suxamethonium – Presentation/s
- 100mg in 2mL polyamp
Suxamethonium – Pharmacology
Depolarising neuromuscular blocking agent
Actions:
- Short acting muscular relaxant
Suxamethonium – Metabolism
- Pseudo-cholinesterase in plasma
Suxamethonium – Primary emergency indication/s
- Complete muscle relaxation to allow endotracheal intubation
Suxamethonium – Contraindication/s
- Known hypersensitivity
- Known history of Suxamethonium apnoea
- Known history of malignant hyperthermia
- Upper airway obstruction
- Severe respiratory distress
- Penetrating eye injury
- Burns > 24hr post injury
- Ruptured AAA
- Organophosphate poisoning
- ECG signs of hyperkalaemia in conditions such as muscle necrosis and renal failure
Suxamethonium – Precaution/s
- Elderly Pts
- Liver disease
- Crush injuries
- Pts who have not fasted
- Airway trauma
Suxamethonium – Route/s of administration
- IV
- IO
Suxamethonium – Side effects
- Muscular fasciculation
- Increased intraocular pressure
- Increased intragastric pressure
- Elevated serum potassium levels
Suxamethonium – Special notes
- Sedation is required prior to use
- Atropine 600mcg should be administered prior to Suxamethonium administration in adult Pts with a HR < 60
- Atropine 20mcg / kg should be administered prior to Suxamethonium administration in children
- A second dose of Suxamethonium usually causes profound bradycardia
- Refrigeration of Suxamethonium is required – requires weekly rotation or disposal when not refrigerated
- Usual dosage:
- Adults: 1.5mg / kg IV (max. dose 150mg)
Suxamethonium – Onset, Peak & Duration times
IV effects:
- Onset: 20 – 40sec
- Peak: 60sec
- Duration: 4 – 6min
Tenecteplase (Metalyse) – Presentation/s
- 50mg in glass vial with weight marked and pre-filled syringe containing water for IV administration (must reconstitute all drug then discard unwanted amount according to weight)
Tenecteplase (Metalyse) – Pharmacology
- Fibrinolytic, a modified form of tissue plasminogen activator (tPA) that binds to fibrin and converts plasminogen to plasmin
Tenecteplase (Metalyse) – Metabolism
- By the liver
Tenecteplase (Metalyse) – Primary emergency indication/s
- Acute STEMI
Tenecteplase (Metalyse) – Contraindication/s (Exclusion Criteria)
- Blood pressure Systolic > 180mmHg; or Diastolic > or = 110mmHg
- Known allergy or hypersensitivity to Tenecteplase or Gentamicin
- Anticoagulant therapy eg. Warfarin, Heparin, Dabigatran, Rivaroxaban, Apixaban
- Glycoprotein IIb / IIIa inhibitors eg. Abciximab, Eptifibatide, Tirofiban
- Active bleeding or bleeding tendency (excluding menses)
- GI bleed within last 1/12
- Active peptic ulcer
- Acute pancreatitis
- Suspected aortic dissection
- Non compressible vascular puncture
- Recent major surgery (< 3/52)
- Traumatic or prolonged (>10min) CPR
- Acute pericarditis
- Subacute bacterial endocarditis
- History of CNS damage eg neoplasm, aneurysm, spinal surgery
- New neurological symptoms
- Significant closed head or facial trauma in past 3/12
Tenecteplase (Metalyse) – Precaution/s (Relative contraindications)
- Age > or = 75 years
- Low body weight
- Renal impairment
- Dementia
- History of stroke or TIA
- Diabetes
- Heart failure
- Tachycardia
- Pregnancy
- Within 1/52 post-partum
- Anaemia
- Advanced liver disease
- Blood pressure between 160 – 180mmHg systolic
- History of bleeding or known prolonged INR
- Peripheral vascular disease
- Administration of Enoxaparin 48 hours prior
- Recent invasive procedures associated with bleeding such as femoral artery puncture; right heart catheterisation
Tenecteplase (Metalyse) – Route/s of administration
- IV, using vial adapter on pre-prepared syringe, as single bolus over 10 seconds
Tenecteplase (Metalyse) – Side effects
- Bleeding – including injection sites, ICH, internal bleeding
- Transient hypotension
Infrequent:
- Allergic reactions including fever, chills, rash, nausea, headache, bronchospasm, vasculitis, nephritis and anaphylaxis
Rare:
- Cholesterol embolism
Tenecteplase (Metalyse) – Special notes
- STEMI – 12 lead ECG shows ST Elevation > or = 1mm in two contiguous limb leads (I, II, III, aVR, aVL, aVF) or ST Elevation > or = 2mm in two contiguous chest leads (V1, V2, V3, V4, V5, V6), new LBBB
- Weight optimised dosing improves efficacy and safety outcomes in drugs with narrow therapeutic index eg. Fibrinolytics
- Other drugs which affect the clotting process may increase risk of bleeding associated with Tenecteplase
Tenecteplase (Metalyse) – Onset, Peak & Duration times
IV effects:
- Onset: N/A
- Peak: N/A
- Duration: N/A