Pain Flashcards
Non-opioid analgesics
Asprin
NSAIDs
Paracetamol
Paracetamol with ibuprofen
Opioid analgesics
Codeine
Fentanyl
Methadone
Oxycodone
Tapentadol
Tramadol
MOA
Opioid analgesic
Opioid analgesics act on receptors in the CNS and GIT producing:
* analgesia
* respiratory depression
* sedation
* constipation
They act mainly at mu-opioid receptors in the CNS, reducing transmission of the pain impulse
Can cause cough suppression
Analgesic indication
Pain
Indication
Opioid and non-opioid analgesics
Pain
Precautions
Opioid analgesics
Taking drugs that cause CNS and respiratory depression, eg benzodiazepines can increase side effects with opioid use
Hypotension, shock—reduced blood volume increases hypotensive risk and increases the risk of respiratory depression; also impairs IM/SC absorption; careful titration of opioid dose required.
Drug interactions
Opioids
- Alcohol.
- Anti-seizure medications, such as carbamazepine (Carbatrol, Tegretol, others)
- Certain antibiotics, including clarithromycin (Biaxin)
- Certain antidepressants.
Practice points
Opioids
- Only take the medication when you feel pain, and for no longer than 3 days
- This medication may make you feel drowsy and may increase the effects of alcohol. If you are affected, do not drive or operate machinery. If you are very sleepy or have trouble staying awake, stop taking the medication and tell your doctor immediately.
- Be careful when you stand up as this medicine might make you feel dizzy if you stand up too quickly.
- This medication can cause constipation. Drink plenty of fluids and take a laxative regularly
- If you have any unused tablets, take them to your pharmacy to be disposed of
- Do not share these medications with anyone else
- Consider take-home naloxone
Indication
NSAIDs
Pain
Inflamation
fever
MOA
NSAIDs
Have analgesic, antipyretic and anti-inflammatory actions. They inhibit synthesis of prostaglandins by inhibiting cyclo-oxygenase (COX) present as COX‑1 and COX‑2:
inhibition of COX‑1 results in impaired gastric cytoprotection and antiplatelet effects
inhibition of COX‑2 results in anti-inflammatory and analgesic action
reduction in glomerular filtration rate and renal blood flow occurs with both COX‑1 and COX‑2 inhibition.
Most NSAIDs are nonselective, inhibiting both COX‑1 and COX‑2. Although selective COX‑2 inhibitors have little or no effect on COX‑1 at therapeutic doses, they are still associated with GI adverse effects.
Differences between non-selective and COX-2 selective NSAIDs
- Nonselective NSAIDs inhibit both COX-1 and COX-2 enzymes to a significant degree.
- Selective NSAIDs inhibit COX-2, an enzyme found at sites of inflammation, more than COX-1, the type that is normally found in the stomach, blood platelets, and blood vessels
Side effects of NSAIDs and why it should be used in caution in some patient groups
- **Indigestion **– including stomach aches, feeling sick and diarrhoea.
- Stomach ulcers – these can cause internal bleeding and anaemia; extra medicine to protect your stomach may be prescribed to help reduce this risk.
- Headaches.
- Drowsiness.
- Dizziness.
- Allergic reactions.
Pharmacological effects and therapeutic uses of paracetamol
paracetamol may be used in all age groups and is preferred to NSAIDs for mild-to-moderate pain as it has fewer adverse effects
if regular paracetamol alone is inadequate for treating pain, adding an NSAID may provide additional analgesia and allow use of lower or intermittent doses of NSAID
in osteoarthritis, regular paracetamol alone is the preferred treatment but is under-used
Kidneys and NSAIDs
- Kidney toxicity – Use of NSAIDs, even for a short period of time, can harm the kidneys. This is especially true in people with underlying kidney disease. The blood pressure and kidney function should be monitored at least once per year but may need to be checked more often, depending on a person’s medical conditions
Paracetamol overdose and treatment
While paracetamol is safe in normal doses, it is hepatotoxic and potentially fatal in overdose. Fortunately, N-acetylcysteine (NAC) is a safe and effective antidote which if used correctly prevents serious hepatic injury after paracetamol overdose.
