Pain Relief Pharmacology Flashcards
(20 cards)
Paracetamol
Presentation, Pharmacology and Metabolism
Presentation: - 500 mg tablets - 120 mg in 5 mL oral liquid (24 mg / mL) Pharmacology: - An analgesic and antipyretic agent Actions: - Exact mechanism of action unclear; thought to inhibit prostaglandin synthesis in the CNS Metabolism: - By the liver; excreted by the kidneys
Paracetamol
Primary Emergency Indications and Contraindications
Indications: - Mild pain - Headache Contraindications: - Hypersensitivity - Children < 1 month of age - Paracetamol already administered within the past 4 hours - Total paracetamol intake within past 24 hours exceeding 4 g (adults) or 60 mg/kg (children) - Chest pain in suspected ACS
Paracetamol
Precautions and Side effects
Precautions:
- Impaired hepatic function or liver disease
- Elderly / frail
- Malnourished
Side effects:
- Hypersensitivity reactions including severe skin rashes (rare)
- Haematological reactions (rare)
Paracetamol
Special notes
- Onset: 30 mins
- Peak: N/A
- Duration: 4 hours
Morphine
Presentation, Pharmacology and Metabolism
Presentation: - 10 mg in 1 mL glass ampoule Pharmacology: - An opioid analgesic Actions: - CNS effects: - Depression (leading to analgesia) - Respiratory depression - Depression of cough reflex - Stimulation (changes of mood, euphoria or dysphoria, vomiting, pin- point pupils) - Dependence (addiction) - Cardiovascular effects: - Vasodilatation - Decreases conduction velocity through the AV node Metabolism: - By the liver, excreted by the kidneys
Morphine
Primary Emergency Indications and Contraindications
Indications: - Pain relief - Acute LVF with SOB and full field crackles - Sedation to maintain intubation - Sedation to enable intubation - RSI Contraindications: - History of hypersensitivity - Renal impairment / failure - Late second stage of labour
Morphine
Precautions and Side effects
Precautions: - Elderly/ frail pts - Hypotension - Resp depression - Current asthma - Resp tract burns - Known addictions to opioids - Acute alcoholism - Pts on monoamine oxidase inhibitors Side effects: - CNS effects: - Drowsiness - Resp depression - Euphoria - Nausea, vomiting - Addiction - Pin-point pupils - Cardiovascular effects - Hypotension - Bradycardia
Morphine
Special notes
- Occasionally wheals can be seen in the line of the vein being used for IV injection. This is not an allergy, only a histamine release IV effects: - Onset: 2 - 5 mins - Peak: 10 mins - Duration: 1 - 2 hours
IM effects:
- Onset: 10 - 30 mins
- Peak: 30 - 60 mins
- Duration: 1 - 2 hours
Fentanyl
Presentation, Pharmacology and Metabolism
Presentation: - 100 mcg in 2 mL ampoule - 200 mcg in 1 mL glass ampoule or cartridge (IN use only) Pharmacology: - A synthetic opioid analgesic Actions: - CNS effects: - Depression - leading to analgesia - Respiratory depression - leading to apnoea - Dependence (addiction) - Cardiovascular effects: - Decreases conduction velocity through the AV node Metabolism: - By the liver; excreted by the kidneys
Fentanyl
Primary Emergency Indications and Contraindications
Indications: - Sedation to facilitate intubation - Sedation to maintain intubation - Analgesia - IV / IN - History of hypersensitivity or allergy to morphine - Known renal impairment / failure - Short duration of action desirable - Hypotension - Nausea and / or vomiting - Severe headache Contraindications: - History of hypersensitivity - Late second stage of labour
Fentanyl
Precautions and Side Effects
Precautions: - Elderly / frail pts - Impaired hepatic function - Respiratory depression e.g. COPD - Current asthma - Pts on monoamine oxidase inhibitors - Known addition to opioids - Rhinitis, rhinorrhea or facial trauma (IN route) Side Effects: - Respiratory depression - Apnoea - Rigidity of the diaphragm and intercostal muscles - Bradycardia
Fentanyl
Special notes
IV effects:
- Onset: Immediate
- Peak: < 5 mins
- Duration: 30 - 60 mins
IN effects:
- Peak: 2 mins
Methoxyflurane
Presentation, Pharmacology and Metabolism
Presentation: - 3 mL glass bottle Pharmacology: - Inhalational analgesic agent at low concentrations Metabolism: - Excreted mainly by the lungs - By the liver
Methoxyflurane
Primary emergency indications and Contraindications
Indications:
- Pain relief
Contraindications:
- Pre-existing renal disease / renal impairment
- Concurrent use of tetracycline antibiotics
- Exceeding total dose of 6 mL in a 24 hour period
- Personal or family history of malignant hyperthermia
- Muscular dystrophy
Methoxyflurane
Precautions and Side effects
Precautions:
- The Penthrox inhaler must be hand-held by the pts so that if unconsciousness occurs it will fall from the pts face. Occasionally the operator may need to assist but must continuously assess the level of consciousness
- Pre-eclampsia
- Concurrent use with Oxytocin may cause hypotension
Side effects:
- Drowsiness
- Decrease in BP and bradycardia (rare)
- Exceeding the maximum total dose of 6 mL in a 24 hour period may lead to renal toxicity
Methoxyflurane
Special notes
- The maximum initial priming dose for Methoxyflurane is 3 mL. This will provide approx 25 mins of analgesia
- Analgesia commences after 8 - 10 breaths and last for approximately 3 - 5 mins once discontinued
- Do not administer in a confined space
- In pts with muscular dystrophy, volatile agents may precipitate life-threatening rhabdomyolysis
Prochlorperazine (Stemetil)
Presentation, Pharmacology and Metabolism
Presentation: - 12.5 mg in 1 mL glass ampoule Pharmacology: - An anti-emetic Actions: - Acts on several central neuro-transmitter systems Metabolism: - Metabolised by the liver; excreted by the kidneys
Prochlorperazine (Stemetil)
Primary Emergency Indications and Contraindications
Indications:
- Treatment or prophylaxis of nausea / vomiting for:
- Motion sickness
- Planned aeromedical evacuation
- Known allergy or C/I to Ondansetron administration
- Headache irrespective of nausea / vomiting
- Vertigo
Contraindications:
- Circulatory collapse (cool, pale, clammy skin, tachycardia, hypotension)
- CNS depression
- Previous hypersensitivity
- Children
- Pregnancy
Prochlorperazine (Stemetil)
Precautions and Side effects
Precautions: - Hypotension - Epilepsy - Pts affected by alcohol or on anti-depressants Side effects: - Drowsiness - Blurred vision - Hypotension - Sinus tachycardia - Skin rash - Extrapyramidal reactions (usually the dystonic type)
Prochlorperazine (Stemetil)
Special notes
IM effects:
- Onset: 20 mins
- Peak: 40 mins
- Duration: 6 hours
