Analgesia Flashcards
sides effects of amitrypilline (for neuropathic pain). TCA
anticholinergic- dry mouth, constipation, urinary retention + sedation, orthostatic hypotension. Prolong QT –> arrhythmias
First line treatment for neuropathic pain?
pregabalin. A GABA analogue
SE of pregabalin?
sedation, peripheral oedema, and weight gain. Can increased Creatinine kinase so keep a look out for it
what are some examples of neuropathic pain?
sciatica, trigeminal neuralgia, phantom limb pain etc.
what is serotonin toxicity? describe the effects
Serotonin syndrome:
- Neuromuscular excitation= increased tone, increased reflexes, clonus
- Autonomic excitation= mydriasis, flush, tachycardia
- CNS excitation= agitation, anxiety, confusion
Occurs when drugs such as pethidine or tramadol is used in conjunction with anti depressant SSRIs
what is the composition of panadeine fort?
Panadeine forte. 500 mg paracetamol + 30 mg of codeine
what is the antidote to paracetamol toxicity?
glutathione (N-actylcysteine)
what receptors detect thermal stimuli?
TRP receptors
WHAT IS THE DOSAGE LIMIT FOR PANADOL?
FOR ADULTS: do not take more than 8 tablets or capsules (500 mg strength) or 6 controlled release tablets each day.
action of tramadol
Binds to mu opioid receptors and also inhibits reuptake of noradrenaline and serotonin.
what is tramadol’s usual dosing?
The usual oral dose of tramadol is 50 – 100 mg, every 4 – 6 hours to a maximum of 400 mg per day. Reduce the maximum daily dose to 300 mg per day in those aged over 75.
first line therapy for mild to moderate pain?
paracetamol
tell me about codeine?
A weak opioid may be considered an alternative to an NSAID when paracetamol alone is inadequate, particularly for people at high risk of NSAID-induced adverse effects.
Codeine is the most frequently used weak opioid but its limitations include its short duration of action (3–4 hours) and the fact that 10% of Caucasians and 1–2% Asians cannot metabolise codeine to morphine (which is its active metabolite producing the therapeutic effect). Ensure adequate dosing, doses below 30 mg are unlikely to be effective.
why might paracetamol be prescribed?
Shared decision making between the prescriber and patient is likely to increase patient adherence to their medication.
Prescribing paracetamol may reduce the cost for the patient.
If a patient is on multiple medications, they are likely to benefit from the PBS safety net, hence prescribing paracetamol will contribute towards the PBS safety and when the safety net is reached, will make the medication cheaper for the patient.
how do we take NSAIDS?
with food
how might we manage chronic non cancer pain?
Morphine long acting oral drug
who should morphine NOT be given to?
Should not be given to:
Asthmatic patients, patients with chronic kidney disease
what are the SE of morphine?
euphoria respiratory depression N and V pupillary constriction reduced GIT motility urticaria/bronchoconstriction
what do we use for breakthrough pain?
fentanyl transdermal patch
how is codeine metabolised?
Metabolised to morphine by undergoing glucuronidation in the liver
why is codeine used in cough syrups?
anti-tussive effects
what sort of drug is fentanyl?
Highly potent phenylpiperidine derivative
why do we need to really adjust for morphine?
morphine glucuronides are excreted in the urine
tell me about tramadol?
often used for Post operative pain
Weak agonist at miu opioid receptors, and weak inhibitor of monoamine reuptake
Can be given orally, IM, or IV
half life of morphine
3-4 hrs
half life of fentanyl?
1-2 hrs
what exactly is Targin?
oxycodone/naloxone combination
which opioids would you avoid in renal impairment?
codeine and pethidine
can you use morphine in renal impairment?
yes… but have to be cautious. avoid if severe renal impairment
