Pain Flashcards
Why is it beneficial to switch one opioid to another?
Increasing dose becomes ineffective
Adverse effects and treatment better balance
Prevent analgesic tolerance
What are the contraindications of acetaminophen?
Allergic reactions
Severe liver failure
What are the adverse effects of aspirin?
GIT- direct corrosive effects = inhibition of PG synthesis
Hypersensitive- potential cross reaction with other NSAIDs
Risk of bleeding (48 hours)
What is the mechanism of action of beta blockers?
Modulation of adrenergic and seratoninergic neurotransmission
In cortical and subcortical pathways
Increases migraine attack threshold
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What are the goals of prophylaxis in Migraine management?
Decrease frequency and severity of attacks as well as debilitating symptoms
Decrease use of small efficacy drugs
Improve quality of life
Aspirin is a ……… inhibitor
Aspirin is a irreversible COX inhibitor
What is the first line drug for mild-moderate pain?
- Naproxen (propionic acid derivative)
Long half life
More potent analgesic
Safest in high risk CVD patients
What drugs are COX-2 coxib inhibitors?
Celecoxib
Etoricoxib
When are opioids used for migraines?
Rarely used
Possible rebound headache and addiction
If other drug managements are contraindicated
Moderate to severe attacks
When is prophylaxis indicated for Migraines?
> 2 attacks/month
Presence of severe or debilitating symptoms
Patients wants to decrease number of attacks
Exaggerated use of abortive therapy drugs
Define pain
Unpleasant and subjective experience
Net effect of ascending and descending neurons
Including biochemical, physiological, psychological and neocortical processes
What are the adverse effects of acetaminophen?
Liver necrosis- toxic doses, chronic alcoholism and hepatitis
Methemoglobinemia & Hemolytic anaemia in G6PD
What is the function of aspirin?
Analgesic
Anti-pyretic
Anti-inflammatory
Decreases nociceptive sensitization and increases pain threshold
What are the types of pain?
Neuropathic
Functional
Nociceptive (preventative)
Inflammatory (preventative)
How are migraines managed using non-opioids?
Non opioid + Metclopromide
Mild to moderate pain
Most commonly used
Less GIT adverse effects
As effective as sumatriptan and more effective than DHE (Dihydroergotamine)
What is the function of Meloxicam?
Oxicam drug class
Selective COX-2 inhibitor
Lower ulcerogenic potential
Long lasting analgesic and anti-inflammatory effects
What are some antiepileptics used in migraine management?
Valproic acid and Divalproex - contraindicated in pregnancy and chronic liver disease
Topiramate
What are the adverse effects of Triptans?
Drowsiness
Dizziness
Paraesthesia
Sensation of warmth
Chest fullness
Nausea
How do you assess pain?
SOCRATES
Number scale 1-10
Patient expectations
Associated Symptoms
Acute or Chronic
Impact of pain on functionality, mental status and behaviour
What is the mechanism of action of antidepressants in migraines?
Downregulates 5-HT2 receptors
Increases NA in synapses
Increased effects of endogenous opioids
When can combination therapy be used with opioids?
Opioid + Non-opioid
Moderate to severe pain
Enhances analgesia and at lower dose of each
Short acting therapy, therefore not indicated for chronic pain
How are dihydroergotamines (DHE) used for migraine management?
Early treatment, during the beginning of attacks
Oral administration
Caffeine combination tablets increase absorption and potentiates analgesic effect
What is the function of acetaminophen?
Analgesic and anti-pyretic
Central analgesic with low potency
Used for mild to moderate pain
Can be used in combination with weak opioids
The choice of drug and route of administration for opioids use depends on?
Comorbidities
Body mass and age
Intensity and perception of pain
Tolerance to opioids
Why convert from one dosage to another in opioids?
Ineffective pain control
Side effects emerge
Change in patient status
Formulatory restrictions
Why do DHE’s have limited use?
Maximum only 2 day use due to risk of fibrosing pleura, pericardium, heart valves and peritoneum
What is the plan for migraine prophylaxis?
Start with small doses, increase until maximal tolerance or expected efficacy is reached
Change drug if adverse effects emerge or if not efficient
Follow up efficiency every 2-3 months : Migraine Diary
What are the adverse effects of opioids?
Nausea, constipation, vomiting
Sedation and hallucinations
Respiratory depression- alhtough tolerance develops to this
Constipation tolerance does not develop- laxative must be prescribed in combination e.g. bisacodyl or senna
Why are 2nd generation triptans better than 1st generation (Sumatriptan)?
E.g. Eletriptan, Frovatriptan, Almotriptan, Naratriptan
Longer half life
Better pharmacokinetics- higher bioavailability
Depending on drug- less adverse effects, more analgesic effect and lower frequency of repeated attacks
What type of pain are NSAID’s best suited for?
Mild to moderate
Pain mediated by PGs e.g. Rhematoid A, Menstrual cramps and post-surgical pain
Minimal use in neuropathic pain
What are the contraindications of coxib COX-2 inhibitors?
Pregnancy and breastfeeding
Hypersensitivity
Liver and kidney dysfunction
GIT active bleeding, peptic ulcer and IBD
<16 yrs
Cerebrovascular disease, Peripheral vascular disease etc
What are the 3 drug groups used for migraine prophylaxis?
Antidepressant, Antiepileptics and Beta Blockers used
Proved efficacy- Metoprolol and valproic acid
Probably efficient- Atenolol and amitriptyline
Possibly efficient- Carbamazepine and pindolol
What opioids are used for mild to moderate pain?
Codeine
Oxycodone
Hydrocodone
Meperidine
What types of antidepressants can be used for migraines?
SSRI
SNRI
TCA
What is the WHO analgesic ladder for pain management
Mild (1-3): non-opioid analgesic
Moderate (4-6): combine acetaminophen/NSAID with moderately potent analgesic
Severe (7-10): high potentcy opioids
What is the mechanism of action of Triptans?
Strong vasoconstrictor of dilated intracranial arteries
Peripheral neural inhibition
Inhibition of neurotransmission of trigeminal-cervical complex
What is opiophobia?
Exaggerated concern over opioid use
Risk > Benefit , therefore not prescribed
Although patients are indicated
What are the side effects of DHE’s?
Chronic headache conversion from chronic use
MI
Ergotism
Nausea & vomiting
Abdominal pain
Diarrhea
Muscle pain and weakness
When can combination therapy be used with opioids?
Opioid + Non-opioid
Moderate to severe pain
Enhances analgesia and at lower dose of each
Short acting therapy, therefore not indicated for chronic pain
When are DHE’s contraindicated?
Liver and kidney failure
Cerebral or peripheral vascular disease
Coronary artery disease
Pregnancy
Lactation
Sepsis
What is the mechanism of action of antiepileptics in migraines?
Increased GABA inhibitory effects
Modulation of glutamate excitatory neurotransmission
Na and Ca channel inhibition
How are headaches classified?
Primary- migraines, cluster headaches, tension-type headaches and trigeminal autonomic headaches etc.
Secondary- head or neck trauma, infection, vascular or non-vascular intracranial disorders etc
What are NSAIDs adverse effects?
GIT irritation- dyspepsia, peptic ulcers & bleeding
Nephrotoxicity- hypoperfusion of kidneys
Antiplatelet effect, Na retention, Liver Dysfunction & CNS dysfunction
Increased risk of CVS events
What are the contraindications of Triptans?
Pregnancy
Lactation
PAD
CAD
MAO inhibitors (including use in previous 2 weeks)
Caution with SSRI or SNRI due to Seretonin Syndrome
What is the first line drug for pain?
- Acetaminophen
What is the mechanism of action of DHE?
Strong arterial vasoconstrictor
What are the contraindications of aspirin?
III trimester of pregnancy
Risk of bleeding
Allergy
Peptic ulcer
Liver or Kidney dysfunction
Co-medication with methotrexate
Children < 16 yrs
Severe decompensated heart failure
What are the contraindications of coxib COX-2 inhibitors?
Pregnancy and breastfeeding
Hypersensitivity
Liver and kidney dysfunction
GIT active bleeding, peptic ulcer and IBD
<16 yrs
Cerebrovascular disease, Peripheral vascular disease etc
When are triptans indicated for migraine management?
Severe or debilitating attacks
Non-specific therapy is ineffective
What drugs are acetic acid derivatives?
Diclofenac
Ketorolac
What opioids are used for moderate to severe pain?
Morphine
Oxymorphone
Hydromorphone
Methadone
Fentanyl
What are the first, second and third line drugs for neuropathic pain?
First line:
Gabapentin
Lidocaine transdermal
TCA e.g. SSRI or SNRI
Second line:
Opioids e.g. tramadol
Third line:
SSRI
Anti-epileptic e.g. carbamezapine, lamotrigine, valproic acid
NMDA anatagonists e.g. Ketamine
