Pain Flashcards
What is classed as chronic pain?
+12 weeks
What is the first step of the WHO analgesic ladder?
Non opioid
- Paracetamol
- NSAIDs inc aspirin
What is the second step of the WHO analgesic ladder?
Weak opioid
- Codeine
- Hydrocodeine
- Tramadol (moderate)
What is the third step of the WHO analgesic ladder?
Strong opioid
- Morphine (CD 2, oral solution <13mg/5ml CD 5)
- Diamorphine
- Oxycodone
- Methadone
- Hydromorphone
- Patches: buprenorphine + fentanyl
What are the adjuvants at every step of the WHO analgesic ladder?
Neuropathic pain:
- TCA: amitriptyline, nortriptyline
- Anti-epileptics: gabapentin, pregabalin
Nerve compression: dexamethasone
Bone metastases: bisphosphonates
Muscle spasms: benzodiazepines, baclofen
What is the dose of paracetamol?
0.5 - 1g every 4-6H PRN
- Max: 4g/day
- Label: do not use more than 2 at any one time. Do not take more than 8 in 24H
- Label: contains paracetamol. Do not take anything else containing paracetamol while taking this medicine. Talk to a doctor at once if you take too much of this medicine, even if you feel well
Overdose: liver damage
- High risk <50kg
- Treatment: acetylcysteine
What is the dose of aspirin?
300-900mg every 4-6H
- Max: 4g/day
- Label: do not take anything else containing aspirin while taking this medicine
What are the side effects of aspirin?
GI irritation → enteric coated
- Label: take with or just after food or a meal
- Enteric coated = slow onset: not used for medical emergency or rapid pain relief
Tinnitus (high dose)
What are the CI of aspirin?
Under 16: reye’s syndrome
- Exception: kawasaki disease
Active peptic ulceration
What are the indications of opioids?
Acute pain
Palliative
Chronic non-malignant pain (short-med term)
- Doses >90mg/day morphine/equivalent = pain specialist
What are the side effects of opioids?
Dependence + tolerance
- MHRA: addiction + dependence w prolonged use in non-malignant pain. Agree treatment strategy + w/drawal plan. Regular monitoring if at increased risk. Consider hyperalgesia if inc pain sensitivity
Respiratory depression
- Antidote: naloxone
- Caution: respiratory disease (asthma)
- MHRA: benzo + opioids: additive CNS depressant effect. Monitor at start, new dose + interaction
Nausea + vomiting (Anti-emetic: metoclopramide)
Constipation
- Osmotic + stimulant laxative
- CI: risk of paralytic ileus
- Caution: IBD
Sedation
Hallucinations + euphoria
Pupil constriction
- CI: head injury, INC intracranial pressure - interfere w neurological assessments
Dry mouth
Hypotension (high dose)
What are the long term side effects of opioids?
- Hyperalgesia - red or switch
- Hypogonadism - red fertility, amenorrhea, erectile dysfunction
- Adrenal insufficiency
What are the interactions of opioids?
CNS depression
- Alcohol
- Benzo
- Z drug
- Sedating anti-histamines
- Barbiturates
- Irreversible MAOIs
What are the indications for codeine and dihydrocodeine?
Mild-moderate pain
- Route: never IV (can cause severe reaction similar to anaphylaxis)
Codeine: diarrhoea, dry cough
- MHRA: cough + cold: restricted use in children: respiratory effects
Use: acute moderate pain in 12+ for 3 days. Max 240mg daily every 6H
CI: breast feeding mothers, ultra rapid metabolisers, children after tonsil/adenoid removed for obstructive sleep apnoea
- MHRA: analgesia: restricted use in children: opioid toxicity
What are the side effects of tramadol?
Psychiatric reactions
RED seizure threshold
- Caution: epilepsy
