Pain Flashcards
What pain is nociceptive pain?
MSK - NSAIDs
Dental pain - NSAIDs
Moderate to severe visceral pain - opioids
Period pain - oral contraceptives, antispasmodics, non-opioids
What is used for neuropathic pain?
TCAs - amitriptyline, nortriptyline
Antiepileptics - gabapentin, pregabalin
Nerve compression by tumour - dexamethasone
What is the pain ladder?
Non-opioids - +/- adjuvant
Weak opioids - +/- non-opioid or adjuvant
Strong opioids - +/- non-opioid or adjuvant
What are the adjuvants used with the pain ladder?
Neuropathic pain - amitriptyline, nortriptyline, gabapentin, pregabalin
Bone metastases - bisphosphonates, strontium ranelate
Nerve compression by tumour - dexamethasone
What is paracetamol used for?
Mild-moderate pain and fever
Preferred in elderly
What is the adult dose of paracetamol?
0.5-1g every 4-6 hours as required. Max. 4g/day
What is the cautionary labels of paracetamol?
Do not take more than 2 at any one time. Do not take more than 8 in 24 hours
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
What does paracetamol overdose cause?
Liver damage
Greater risk if < 50kg
What is used to treat paracetamol poisoning?
Acetylcysteine
What are the overdose symptoms of paracetamol?
Nausea, vomiting, right subcostal pain/tenderness
What is aspirin used for?
Antiplatelet
Fever and pain
What is the dose of aspirin for ACS, TIA?
300mg dispersible tablets
What is the dose for secondary prevention of thrombotic arterial events?
75mg OD for life
What is the dose of aspirin for fever and pain?
300-900mg every 4-6 hours as required
Maximum 4g per day
What is the cautionary label for aspirin?
Take with or just after food or a meal
Contains aspirin. Do not take anything else containing aspirin while taking this medicine
What are the side effects of aspirin?
GI irritation
Tinnitus in high doses
What are the contraindications of aspirin?
< 16 years as causes Reye’s syndrome
Unless Kawasaki or as an antiplatelet
Salicylate or NSAID hypersensitivity
What are the interactions of aspirin?
Increased risk of bleeding - antiplatelet or anticoagulants e.g. warfarin
How do the opioids work?
Acts in various opioid receptors located in the brain, spinal cord and other nervous tissue to relieve pain
What are the weak opioids?
Codeine - CD5, injections = CD2
Dihydrocodeine - CD5
Meptazinol - POM
What are the moderate opioids?
Tramadol - CD3, exempt from safe custody
What are the strong opioids?
Morphine - CD2, oral solution 13/5 or less CD5 Oxycodone - CD2 Diamorphine - CD2 Buprenorphine - CD3 Fentanyl - CD2 Methadone - CD2 Hydromorphone - CD2
What are the other opioids and their uses?
Alfentanil - CD2 intraoperative analgesia Remifentanil - CD2 intraoperative Pethidine- CD2 labour Dipipanone - CD2 Papaveretum - CD2 Pentacozine - CD3 Sufentanil - CD2 Tapentadol - CD2 less nausea and vomiting
What is the rescue dose for breakthrough pain?
1/10 - 1/6 total daily dose every 2-4 hours as required
Immediate release preparations
What is used for an opioid overdose?
Naloxone
What are the symptoms of opioid overdose?
Coma
Pinpoint pupils
Respiratory depression
How does naloxone work?
Opioid receptor antagonist
Reverses respiratory depression
Can be supplied without prescription
What are the side effects of opioids?
Dry mouth Nausea and vomiting Constipation Sedation Reduced concentration and confusion Euphoria and hallucinations Dependence and tolerance Respiratory depression Hypogonadism Adrenal insufficiency Hyperalgesia
What is the mnemonic of opioid side effects?
MORPHINE
Miosis Out of it Respiratory depression Postural hypotension Hyperalgesia Infrequency Nausea and vomiting Euphoria
What are the contraindications of opioids?
Comatose patients
Risk of paralytic ileus
Respiratory depression
Head injury or raised intracranial pressure
What are the interactions of opioids that cause increased sedation?
Antidepressants Antihistamines Alcohol Z-drugs Antipsychotics Antiepileptics Benzodiazepines
What opioid interaction can cause CNS excitation or depression?
MAOIs
What are the cautionary labels for opioids?
This medicine may make you sleepy
If this happens do not drive or use tools or machines
Do not drink alcohol
What is oral morphine used for?
Severe pain in palliative care and coughs
What are the main side effects of morphine?
Causes most euphoria, nausea, vomiting
What is the dose of oral morphine?
Every 4 hours for immediate release
12-24 hourly MR
What is the maximum dose increments for oral morphine?
1/3 or 1/2 of total daily dose per 24 hours
What is the equivalent parenteral dose of oral morphine?
Half the oral dose
What is the schedule of morphine?
CD5 for solutions but if over 13mg/5ml then CD2
What is a morphine alternative?
Oxycodone
Why is diamorphine preferred when administering parenterally?
More soluble and smaller volumes can be injected in emaciated patients in palliative care
What is the diamorphine equivalent dose compared to oral morphine?
1/3 oral morphine
Does diamorphine have more or less nausea and hypotension than morphine?
Less
100 mg codeine PO is equivalent to how much morphine PO?
10mg PO morphine
3mg diamorphine IM is equivalent to what dose of tramadol PO?
100mg tramadol
100mg dihydrocodeine PO is equivalent to how much tramadol PO?
100mg tramadol
How much oxycodone PO is equivalent to 5mg morphine IM?
6.6 mg
How much hydromorphone PO is equivalent to morphine IM 5mg?
2mg hydromorphone
What is buprenorphine?
Partial agonist - precipitates withdrawal symptoms
Effects are only partially reversed by naloxone
Sublingual for opioid dependence
What is the risk with fentanyl patches?
Risk of fatal respiratory depression in opioid naive patients
What are the counselling points for fentanyl patches?
Immediately remove patch in case of breathing difficulties, marked drowsiness, confusion, dizziness, impaired speech. Seek prompt medical attention
What do you reduce the new opioid dose by due to hyperalgesia in fentanyl use?
1/4 to 1/2
Are fentanyl patches suitable or unsuitable in acute pain or rapidly changing pain?
Unsuitable It is given when dose and pain level is stable
What do you need to avoid when using fentanyl patches?
Exposure to external heat as increases absorption
Avoid hot baths/sauna. Monitor if fever present
How do you apply transdermal opioid patches?
Apply to dry, non-irritated and non-hairy skin on upper torso or upper arm
Rotate patch site after each use
What is the equivalent dose of morphine salt to a fentanyl 100 patch?
240mg
What is the equivalent dose of morphine salt to a fentanyl 75 patch?
180mg
What is the equivalent dose of morphine salt to a fentanyl 50 patch?
120mg
What is the equivalent dose of morphine salt to a fentanyl 25 patch?
60mg
What is the equivalent dose of morphine salt to a fentanyl 12 patch?
30mg
What is the equivalent dose of morphine salt to a buprenorphine 5 patch?
12mg
What is the equivalent dose of morphine salt to a buprenorphine 10 patch?
24mg
What is the equivalent dose of morphine salt to a buprenorphine 15 patch?
36mg
What is the equivalent dose of morphine salt to a buprenorphine 20 patch?
48mg
What is the equivalent dose of morphine salt to a buprenorphine 35 patch?
84mg
What is the equivalent dose of morphine salt to a buprenorphine 52.5 patch?
126mg
What is the equivalent dose of morphine salt to a buprenorphine 70 patch?
168mg
What is codeine used for?
Mild to moderate pain 30-60mg every 4 hours
Codeine linctus in dry or painful cough
Acute diarrhoea
What is the MHRA advice for codeine?
Restricted use in children due to reports of morphine toxicity
For acute moderate pain in children above 12 years only if it cannot be relieved by other pain,illness such as paracetamol or ibuprofen alone
Children aged 12-18 years max 240mg daily for 3 days up to 4 times a day with no less than 6 hour intervals
Not recommended in children with compromised breathing
What are the contraindications of codeine?
Ultra rapid metabolisers
Children under 18 who undergo removal of tonsils or adenoids for treatment of obstructive sleep apnoea
Can you give codeine in breastfeeding mothers?
Do not give codeine to breastfeeding mothers, passes to baby through breast milk
What are the counselling points for codeine?
Recognise signs and symptoms of morphine toxicity
Stop and seek medical attention if reduced consciousness, lack of appetite, somnolence, respiratory depression, constipation, pinpoint pupils, nausea and vomiting
What is the MHRA advice for codeine in coughs and colds?
Restricted use in children
Not recommended in 12-18 years with breathing problems
What are the contraindications of codeine?
Children under 12
Ultra rapid codeine metabolisers
Breast feeding mothers
What is the route if administration of codeine and dihydrocodeine?
Never IV as severe reaction similar to anaphylaxis
What is the MHRA advice for dihydrocodeine?
Prescribe and dispense co-dydramol by strength to minimise risk of medication error and risk of accidental overdose
How does tramadol work?
Moderate opioid
NA and 5HT reuptake inhibitor
What are the side effects of tramadol?
Increased risk of bleeding
Lowers seizure threshold
Psychiatric reactions
What are the interactions with tramadol that lowers seizure threshold?
SSRIs
TCA
Antiepileptics
What are the tramadol interactions that increase the serotonergic effect and therefore the risk of serotonin syndrome?
SSRIs
TCAs
5-HT1 agonists
MAOIs
What are the tramadol interactions that increase the risk of bleeding?
Warfarin
What is a migraine?
Moderate/severe headache felt as a throbbing pain on one side of the head
What are the symptoms of migraine?
Intense throbbing headache on one side of the head
Nausea and vomiting
Sensitivity to light or sound
What is an aura?
Temporary warning symptoms before a migraine
Visual disturbances
Numbness or pins and needles
Dizzy, off balance
Difficulty speaking
What is used to treat migraine?
5HT1 receptor agonists (triptans)
Sumatriptan
Zolmitriptan
Ergot alkaloids - ergotamine do not repeat in less than 4 days, limited to use twice a month to avoid habituation
NSAID - tolfenamic acid
What is used for prophylaxis of migraine?
Propranolol
Anti epileptics - topiramate, valproate, gabapentin
TCAs
Pizotifen
What is used for acute migraine attacks first line?
Simple analgesic (dispersible)
What is used for acute migraine attacks second line?
5HT1 agonist (sumatriptan) can combine with NSAID
Ergotamine rarely used
What antiemetics are used for acute migraine attacks?
Metoclopramide
Domperidone
Buclizine
Prochlorperazine
When is migraine prophylaxis used?
At least 2 attacks a month
Increasing frequency of headaches
Significant disability despite treatment for migraine attacks
Can’t take suitable treatment for migraine attacks
What is the mechanism of action of the triptans?
Act on 5HT1D and 5HT1B present on cranial arteries and veins to cause vasoconstriction
What are triptans used for?
Treatment of acute migraine
What is the dose of triptans?
One dose ASAP after onset, second dose at least 2 hours later if migraine recurs
Do not take second dose for same attack
What are the side effects of triptans?
Coronary vasoconstriction or anaphylaxis
What are the contraindications of the triptans?
Ischaemic heart disease
MI
TIA
Not for hemiplegic, basilar or opthalmoplegic migraines
What are the counselling points for triptans?
Stop if intense tingling, heat, heaviness, pressure or tightness in any part of the body
What is used for neuropathic pain?
TCA - amitriptyline
Gabapentin
Pregabalin
Morphine and oxycodone by specialist
Tramadol
Corticosteroids - compression neuropathy
Trigeminal neuralgia - carbamazepine or phenytoin