HNN215 Exam Notes:
Week 1: Medicines used to treat pain
Intended learning outcomes:
² Explain the mechanism of action of the following classes of analgesic agents ² Non-narcotics:
Paracetamol (Panadol):
- Mild to moderate pain
- Provide analgesic affect by inhibiting prostaglandin synthesis in the CNS and activating descending pathways
- Also has antipyretic (reduces temperature)
- Significant risk of hepatotoxicity or liver toxicity with elevated doses - Important to monitor liver function
- Nursing care - must be mindful of the different strengths NSAIDS:
Ibuprofen, diclofenac, celecoxib
- Reduce pain and inflammation due to tissue injury
- NSAIDS have analgesic, anti-inflammatory and anti-pyretic actions
- Inhibit production of prostaglandins by blocking COX, reducing inflammation and producing analgesia - Prostaglandins are released as part of the inflammatory response to injury and they enhance the
transmission of pain
- Side effects include GIT bleeding, NSAID induced renal impairment and increased risk of CV events - Nursing care – use lowest effective dose over the shortest period of time, ensure renal function is
monitored Narcotics:
Morphine, Endone/oxycodone, targin, fentanyl
- Preparation includes either - IV, IM, oral, sublingual, subcutaneous, transdermal patch - Indicated for acute or chronic pain, mild, moderate to severe pain
- Work by acting on opioid receptors in CNS and gastro-intestinal tract producing analgesia
- The effect of individual narcotics may vary depending on their affinity for opioid receptors as pure of partial agonists of these receptors
- pure opioid agonist à morphine
- antagonist to the opioid receptor is à naloxone (a drug that can be given to reverse the effects of the narcotics analgesic)
- mixed opioid agonist à targin (combines oxycodone (agonist) and naloxone (antagonist). This reduces the side effects while still providing pain relief)
- Adverse effects include, CV compromise (hypotension/bradycardia), respiratory depression - Nurses must accurately assess sedation and associated side effects
- May also cause constipation, must be given a laxative - Controlled drugs
² Identify the significant risks related to these classes ² Non-narcotics:
- Significant risk of hepatotoxicity or liver toxicity with elevated doses NSAIDS:
- Nausea - Dyspepsia
- GI ulceration or bleeding
- Raised liver enzymes (especially diclofenac) - Diarrhoea
- Headache - Dizziness
- Salt and fluid retention - Hypertension
Narcotics:
- Nausea and vomiting - Dyspepsia
- Drowsiness - Dizziness - Headache - Orthostatic - Hypotension - Itch
- Dry mouth - Miosis
- Urinary retention - Constipation
² Describe nursing actions to prevent, identify and manage the significant risks ² Non-narcotics:
- Nursing care - must be mindful of the different strengths NSAIDS:
- Nursing care – use lowest effective dose over the shortest period of time, ensure renal function is monitored
Narcotics:
- Nurses must accurately assess sedation and associated side effects
² Explain the benefit of regular analgesic dosing versus PRN analgesic dosing in relation to steady state concentration ²
Therapeutic range:
- This is where the level of drug is above the minimum effective concentration
- When we have a drug that we want to be working constantly, we want to get the steady state concentration where they are sitting above the minimum effective concentration
- Most drugs have four or five half lives. For example, if you take one drug (1000 micrograms), 4 hours later half of its affect has worn off (500 micrograms) and this will continue to decrease. However, if you give them another dose 4 hours after the first dose this will increase their dosage (1500 micrograms).
Eventually the patient will have an equal amount going into the body is what is going out of the body (1000 micrograms will increase to 2000 micrograms after another dosage, which will drop back down to 1000 micrograms within the 8 hours until another dosage is given)
- Loading dose is giving them 2 doses and then when it falls they will stay in the steady state concentration Other notes:
Optimising the use of the national standard medication charts (NSMC)
- The NSMC are designed to reduce the risk of medication errors and to assist health professionals in communicating clear instructions regarding medicines
The following information is required on each medication chart:
- Patient identification, including name of patient, date of birth, unique record number (URN) and gender - A completed allergies and adverse drug reactions (ADR) alert section
The following information is required for each medicine order on the chart:
- The date the medicine is prescribed – this is the date that the medicine order is written. It is not the date that the medicine was originally ordered, which may be earlier
- Medicine name
- Where applicable for slow release dose forms ‘Tick if slow release’ box ticked - Route of administration using accepted abbreviations
- Frequency of administration using accepted abbreviations
- Administration times using ‘Recommended administration times’ (note this is not applicable to ‘as required PRN medicine’ orders)
- Prescriber signature with their name must be printed at least once on that medication charts so they can be identified and contacted if required