Central Nervous System Flashcards
What are the steps of the pain ladder?
Paracetamol
Paracetamol + Weak opioid
Paracetamol + strong opioid
+/- adjuvants
What are the main side effects of opioids?
Sedation and anxiolysis, respiratory depression (combination of opioids and alcohol is particularly dangerous) Cough suppression pupil constriction nausea and vomitting Constipation
Which kinds of pain are opioids effective on?
acute and cancer pain
effectiveness questionable in chronic non cancer pain
Not effective in neuropathic pain
What is one of the main issues with opioids
Highly addictive
What is opioid induced hyperalgesia
Enhanced pain in response to opioid
What is the first choice regular strong opioid?
Morphine, unless renal impaired
Why is morphine not indicated in renally impaired patients?
Because of active metabolite accummulation, Chronic kidney disease stage 3-5 or creatinine clearance below 30ml/min should not be used.
How would you start morphine dosing?
Morphine sulfate MR in two divided doses, rounded to the nearest 10mg. Then add morphine sulfate oral solution 1/6th of the total daily dose every 4 hours as required, rounded to the nearest 5mg
How can morphine be given in patients with swallowing impairments?
Morphine sulfate modified release capsules can be opened and the contents swallowed without chewing, contents can also be given via PEG tube.
How should you increase a patients morphine dose?
Remember to include breakthrough dose into the TDD. The new daily dose is the accumulation of these doses over the day. Calculate new breakthrough dose 1/6th of TDD and round to nearest 5mg.
What are NSAIDs
drugs that act to relieve inflammation but are not structurally related to corticosteroids. They are analgesics, antipyretics and anti-inflammatory drugs.
What are the common adverse effects of NSAIDs?
Platelet dysfunction, inhibition of COX1, gastritis and peptic ulceration, acute renal failure, sodium and water retention and oedema, analgesic neuropathy, prolongation of gestation and inhibition of labour, hypersensitivity
How does paracetamol work?
inhibition of prostaglandins
How are anticonvulsants/anti-epileptics used for pain relief?
carbamazepine, tricyclic antidepressants. Follow neuropathic pain ladder
Discuss the use of paracetamol at step 1 of the pain ladder
Generally safe at therapeutic doses up to 4g per day in adults orally.
Risk factors for hepatotoxicity: low body weight, elderly/frail, cardiac pulmonary or renal insufficiency, malnourished, alcohol misuse disorder, hep c. If eGFR less than 30ml/min/1.73m2 dose interval minimum of 6 hours. IV dose is weight adjusted
Discuss the use of NSAIDs for pain
CV/GI, Renal dysfunction risks. Assess risk vs benefit, use for shortest time possible, be aware of adverse effects, gi protection.
Small increased risk of thrombotic events, greater risk at higher doses and long term. Lower risk with naproxen or ibuprofen at low dose
Diclofenac: contraindicated in ischemic heart disease, peripheral arterial disease, cerebrovascular disease, congestive heart failure. Risk of GI event higher in older people, avoid a combination of NSAIDs. Can precipitate renal failure, increased risk of with hypovolemia, or concomitant administration with ACE inhibitors, ARB, diuretics
What are the 3 safe steps for starting an NSAID
3 SAFE STEPS: don’t use unless you have to, consider topical NSAIDs ahead of oral for osteoarthritis, if they have to be used then balance benefits and risks, use a safer drug at lowest effective dose for the shortest period of time, high priority for medications review, consider gastroprotection
What must be taken into account with codeine/hidryocodeine?
They have a ceiling effect
When should tramadol be prescribed?
Only if first line weak opioids arent tolerated as it interacts with other medications, can lead to low seizure threshold
What non-pharmacological statergies can be used for pain management?
Psychological based therapies, CBT, physical therapy, exercise, electrotherapy, accupuncture
Describe migraine
can have triggers, presents with aura, and one sided pain in the head usually.
Discuss management of migraines
Reduction of triggers, keep a headache diary, review medications that may cause headache, pharmaceutical treatments
What medications can exacerbate migraines?
Oral contraceptive, HRT, medication overuse
What pharmaceutical treatment can be offered for migraine?
simple analgesia, triptan + paracetamol or NSAID, or anti emetic if needed