analgesics Flashcards
What are the 2 modalities of pain?
1- perception: physical component of pain. This is unversal for everyone
2- reaction: psychological component of pain. This varies greatly for people
What is an analgesic?
a drug that relieves pain
What are the 7 ideal properties of an analgesic?
1- maximum effects by all routes of administration 2- rapid onset, long duration 3- dull the pain and diminish anxiety 4- minimal adverse effects 5- minimal narcosis 6- minimal tolerance 7- non addictive
what are the 3 ways to provide pain relief?
1- Blockade of nerve impulses by local anaesthesia or surgical section of a nerve.
2- Alteration of the perception of pain
3- Alteration of the reaction to pain.
what are the 2 group analgesics are divided into?
1- non opioids: non-narcotic, peripheral, mild and antipyretic
2- opioids: narcotic, central and strong
What are non-opioid analgesics?
how do they work?
- NSAIDs (non-steroidal anti-inflammatory drugs) and salicylates
- inhibit the enzyme COX which inhibits the prostaglandin at the site of pain and inflammation
What are some examples of non-opioid drugs?
- aspirin
- paracetamol
- ibuprofen
What are opioid analgesics?
how do they work?
- these occur naturally or are synthesised
- they interact with specific opioid receptors and can cause pre-synaptic inhibition or post-synaptic inhibition
What are some examples of opioid drugs?
- morphine
- codeine
- co-codamol
- pethidine
- dihydrocodeine
What are the adverse effects of aspirin?
- GI: nausea, vomiting
- bleeding
- renal damage
what are the contraindication for aspirin?
- not to be given to children under 12 years
- not to be given to pregnant women and breasfeeding
What are the adverse effects of paracetamol?
- hepatic: produces toxic metabolite
- nephrotoxicity: long term consumption
- avoid in patients with pre-existing kidney condition
what are the indications for paracetamol?
- pregnant/breastfeeing
- patients on warfain
- patients sensitive to aspirin
- patients with asthma
- children
What are the adverse effects of ibuprofen?
- GI: peptic ulceration, gastric bleeding
- CNS: headache, dizziness
- bleeding
- pregnancy: avoid in 3rd trimester
What are the adverse reactions of opioid analgesics?
- respiratory depression
- pinpoint pupils
- constipation
- nausea
- urinary retention
