Groups of analgesic drugs Flashcards
Uses of opioids
Moderate to severe acute and malignant pain
Titrate to pain - balancing pain needs against side effects
No maximum dose
3 groups of analgesic drugs
Opioids
Non Steroidal Anti-inflammatory Drugs
Adjunct analgesia
Helpful effects of opioids
Analgesia
Relief of anxiety
Sedation
Euphoria
Unhelpful effects of opioids
Respiratory depression (bronchospasm)
Nausea and vomiting
Cough suppression (increased risk of chest infection)
Cardiovascular depression (may result in bradycardia and hypotension)
Constipation due to reduction of smooth muscle contraction
Itching
Tolerance
Addiction
Common Opioids - Morphine
Morphine - Natural, most effective agains dull and continuous pain than sharp and intermittent pain. Used for post and intra op pain. Histamine release is common
-PONV so usually given with anti-emetic drug
Dose IV 10mg in 10ml for Anaesthetics - 5/6 mg dose, Recovery 1-2mg
Duration 2-3 hrs
Opioids in common use - Fentanyl
Synthetic
Short acting 30mins
Rapid onset (1-2 mins) Peak effect (5-6 mins)
100 times more potent than morphine
Dose 50-100 micrograms. (given in smaller doses than morphine) Comes in 2ml and 10ml amps of 50 micrograms/ml
Opioids in common use - Remifentanil
Quick onset (1-2 mins
Rapid offset (3-6 mins)
Potent respiratory depression
Used purposely to produce hypotensive anaesthesia to lessen bleeding
Often used as intra op infusion
Precise intra-operative control and fast clear headed recovery makes it particularly suitable for continuous infusion.
Available in 1mg and 2mg vials.
Opioids in common use - Alfentanyl
Powerful short acting version of fentanyl
(5-10 mins) duration)
Suitable for TIVA
Good for day surgery patients as so short acting they are good to go home
Opioid antagonist drug is
Naloxone (Narcan)
Action of Naloxone
Reverses analgesia as well as respiratory depression
Duration of action is 30 - 60 min
Dose is 400microgram causes response in 2 mins
Difference between Doxapram and Naloxone
Doxapram is a central and respiratory stimulant. This drug stimulates respiration while maintaining effective pain relief. Naloxone reverses analgesia as well as respiratory depression
Why is it necessary to observe patients closely when naloxone has been administered?
Duration of action of Naloxone is 30-60 mins which is less than the action of some opioids. So respiratory depression may reappear after naloxone has worn off
Features of Non steroidal anti-inflammatory drugs
Anti - inflammatory
Anti-pyretic
Analgesic
Contraindications to the use of NSAIDS
Renal insufficiency Peptic ulceration Hiatus hernia Asthma Clotting/bleeding disorders
Uses of NSAIDS
Mild to Moderate pain eg back pain, headaches, post-op pain, soft tissue injuries
Good for pain caused by swelling, not so good for non inflammatory pain
No addictive
May be given to reduce the amount of opiods
Maximum does must not be exceed
Diclofenac use is contraindicated in those with
ischaemic heart disease
peripheral arterial disease
cerebrovascular disease
established congestive heart failure
Commonly use NSAID
Diclofenac
Keterolac
Ibuprofen
Aspirin
Maximum dose of Diclofenac (Voltarol)
150 mg in 24 hours. Very sore if given IM. Can be given PO, PR. IV
Example of Non opioid analgesia
Paracetamol
Used to treat acute pain in combination with other analgesics
Max dose is 4g per day
Examples of adjunct analgesia
Steroids
antidepressants
muscle relaxants
caffeine (increases analgesic effect of aspirin/paracetamol
Uses of adjunct anaethesia
May relieve pain in certain situations
Treat pain or symptoms associated with pain, e.g. sleep disturbance
What information can be found on a drug information leaflet (7)
Indications for use Dose Contra-indications Warnings Drug interactions Side effects Storage
