Analgesia Flashcards
What is porphyria variegate?
Genetic disorder. Deficiency in any enzyme in haem biosynthetic pathway. Accumulation of haem intermediaries.
How confirm porphyria variegate diagnosis?
Test urine Ala and PBG
Name 3 triggers porphyria variegate
• Drugs: barbiturates!, diazepam, ketorolac, phenytoin, birth control pills, sulfonamides
• stress (give midazolam premed)
• hypoglycaemia
• sunlight
Dehydration (fluid load 10% dextrose with electrolytes)
Treatment porphyria variegate attack? (4)
• Stop precipitating drug
• hydrate with 10% dextrose-saline infusion
• treat symptoms: pain, seizure (midazolam), ht, tachy
• haem arginate official treatment
Which agents are definitely safe in porphyria variegate? (9)
• Succinylcholine
• Atropine
• neostigmine
• pancuronium
• nitrous oxide
• procaine
• meperidine (pethidine)
• fentanyl
• morphine
Regional anaesthesia, ketamine, etomidate controversial.
Thiopentone absolute contraindication!!
Which analgesic targets secondary hyperalgesia with andromic release of substance p?
Capsaicin
Which 3 analgesics target NMDA receptors?
• Ketamine
• magnesium.
Dextromethorphan
Nitrous oxide
Xenon
Which 2 analgesics target GABA receptors?
• Pregabalin
• gabapentin
Which 2 analgesics target descending alpha 2 pathway?
• Clonidine
• Dexmedetomidine
Name an opioid receptor antagonist
Naloxone
Which opioids target mu receptor in brain, brainstem and spinal cord and what effects do they have? (5)
Analgesia, euphoria, respiratory depression, constipation
•Morphine
• fentanyl
• met-enkephalin
. B-endorphin
Which opioids target kappa receptor in brain, brainstem, hypothalamus and spinal cord and what effects do they have? (3)
Spinal analgesia, sedation, dysphoria
• morphine
• oxycodone
Which opioids target delta receptor in telencephalon and spinal cord and what effects do they have? (3)
Analgesia, antidepressant, dependence
-leu-enkephalin
-B-endorphin
When should opioid be prescribed?
Only for severe pain because most potent analgesics
Name 3 long acting opioids
-morphine (longest)
-tramadol
-pethidine
Name 2 medium acting opioids
Fentanyl
Sufentanyl
Take 3-5 minutes, work for 30-60 minutes
Name a short acting opioids
Alfentanil
1 minute onset, very potent, last about 10 minutes
Name an ultra short acting opioids
Remifentanil. 3 minutes and fastest onset of 2 min
Name 6 side effects cox2 inhibitors and NSAIDs
-renal impair
-gastric ulceration
-inhibit platelet aggregation (thrombosis)
-bronchoconstriction
-fluid retention
-PDA closure fetus
COX2 specific increase risk MI
Name 4 NSAIDs that have Full COX 1 and 2 inhibition
Full COX 1 and 2 inhibition
-aspirin (irreversible)
-ibuprofen
-diclofenac
-naproxen
-indomethacin
Name 3 NSAIDs with preferential COX2 and partial 1inhibition
Nimesulide
Meloxicam
Etodolac
Name 3 NSAIDs with primary COX2 and minimal 1inhibition
Etoricoxib
Celecoxib (sulfonamide)
Rofecoxib
Name 3 NSAIDs with weak COX2 and 1inhibition
Paracetamol
5-ASA (mesalazine)
sulfasalazine
Similarity between mivacurium and cocaine.
Both metabolised by buteryl cholinesterase
Analgesic agent of choice for trauma patients with gross hypovolaemia?
Opioids and paracetamol
NSAIDs contraindicated!
Which 2 receptors does morphine target?
Mu and kappa opioid receptors
Which analgesic agent is deleterious for the shocked hypovolaemic patient?
Ketorolac (NSAID)
Describe the WHO pain ladder.
Multimodal step-up approach!
1. Non opioid: paracetamol
2. NSAID
3. Weak opioid: tramadol codeine
4. Strong opioid morphine
Can give adjuncts with these eg ketamine, dexmedetomidine, regional,steroids (gabapentin- chronic pain)
Which analgesic is good to give with TIVA infusion?
Remifentanil
• ultra short acting
• doesn’t build up in body: organ independent breakdown
Which analgesic agents are good for short airway procedures eg bronchoscope?
Alfentanyl
• good intubation response, very potent
• short acting, last about 10 minutes
Which analgesic is best to use for induction and intra-op acute pain?
Fentanyl and sufentanyl
Give example of multimodal analgesia in a patient undergoing hysterectomy
• Fentanyl: preop and intra-op boluses
. Regional: tap
• paracetamol
• morphine o, 1 mg/kg every 4 hours towards end surgery and post-op (patient controlled best, give 1 mg every 5-6 minutes)
• NSAIDs post op if candidate
Dose fentanyl?
1 ug/kg (0,001 mg)
Dose sufentanyl?
0,1 ug/kg (0,0001 mg)
Analgesic opioid of choice in asthmatics?
Pethidine (meperidine)
Synthetic opioid so less bronchospasm
Side effect tramadol?
Very pro-emetic
Name 5 side effects naloxone
• tachycardia
• hypertension
• myocardial ischaemia
• cardiac failure
• pulmonary oedema
Name 3 side effects flumazenil
Arrhythmia, ht, convulsions
Atropine class/moa? NB
Antmuscarinic. Antagonise ach and work on exocrine glands to decrease secretions, smooth muscle (bronchoditation), cardiac (tachy), CNS
Cox 1 vs cox 2? (2)
• Cox 1 generates prostaglandins involved in protection gi mucosa vs prostaglandins that mediate inflammation and pain all over body
• Inhibitors more gastric side effects and bleeding risk vs less
Name 8 side effects morphine
Morphine
Myosis
Out of it (sedation)
Respiratory depression
Pneumonia (aspiration)
Hypotension
Infrequency (constipation, urinary retention )
Nausea
emesis
Which fibres are responsible for the transmission noxious stimuli? (2)
= elicit tissue damage and activate nociceptors. AKA pain.
• C fibres !
• A delta fibres
Flumazenil class?
Selective GABA A receptor antagonist
(Antag Benzo)
