Pain:|Opiods

Pharmacological Treatment in Pain Management – Analgesics

Non-Opioids • Acetaminophen – (Paracetamol). • Non-Steroidal-Anti-Inflammatory Drugs(NSAID’s). All non-opioids have a “ceiling” or limit to their analgesic efficacy – once the maximum oral dose is reached further oral doses will not have a greater analgesic effect.

Opioids • weak opioids • strong opioids Adjuvant medications (Co-Analgesics)

Morphine (opioid – a narcotic)

Side effects of opioids

• Sedation/drowsiness – (opioids are narcotics and induce narcosis, risk of falls is increased) • Cognitive changes – Euphoria (careful not to acknowledge that patient is not in pain), Delerium, Confusion • Decreased respiratory rate – Respiratory depression • Constipation - Severe • Nausea • Vomiting • Pruritus • Urinary retention • Hypotension

Management of side effects - Opioids

Use WHO analgesic ladder. • Administer opioid - low and slow. • If pain relief is satisfactory - decrease the dose by 25 – 50%. • Consider a non-opioid. • Involve specialists in pain management –specialist nurse in pain management, palliative care.

Pruritus (itching) • aggravated by heat or a tendency to skin allergies. • administer prescribed antihistamine (Piriton, Benadryl, Claritin, Zyrtec).

Hypotension • assess BP and caution when changing posture due to risk of a fall. • assess hydration and correct dehydration.

Oral care Dryness of mucous membranes – oral care essential and use of an oral assessment tool if neutropenic.

Respiratory depression;can occur if rapid dose escalation for acute or if additional dose fmust assess respiratory rate every 10 - 15 minutes aespecially with dose initiation and escalation. • opioids should be withheld, if the patient is sedated when awake (rouseable) or whenever the RR is ≤8/min. (APS 1999; Pasero et al., 1999) • inform medical team. • naloxone (narcan / nalone) – antidote to opioids, (initially 400micrograms, IV, SC, IM titrate upwards according to patient’s response.

Opioids & use in the elderly

morphine sulphate (Cyclimorph) – choice • (Mann & Carr,2006) • Oxycodone – as Oxycontin (immediate release (IR) and controlled or modified release (MR) for acute pain. • Immediate release opioids should be available for breakthrough pain i.e., oramorph.

•• Use least invasive & safest route – Oral (immediate release & sustained release). • If unable to tolerate oral medication, consider- buccal, sublingual, rectal or transdermal patches. • I V (PCA) or Epidural – post operative or in severe pain I M – avoided, if possible, • elderly tend to have less subcutaneous & muscle tissue. • slow absorption and delayed effects. • prolonged effects & toxicity with repeated IM injections due to altered analgesic serum levels

Opioid therapy; commence with 25 - 50% of adult dose and slowly increased by 25% increments on an individual basis, i.e individualized approach. (AGS 1998; APS 1999; Pasero et al.1999; Vigano et al 1998) Consider 25 – 50% increments until there is 50% reduction in pain rating or satisfactory pain relief. (APS 1999) Repeat dose may be safely administered at time of peak pain if previous dose is ineffective and side effects are minimal.

Adjuvant Analgesia

adjuvants – potentiate the activity of another drug. (co-analgesics’.)

• Frequently used with opioids to minimize dosage of an opioid – opioid sparing • Usefulness depends on cause of pain or other symptom concurrent with pain. • More effective for neuropathic or nerve pain.

Local anaesthetics – applied as pain patches i.e., versatis pain patches have lidocaine – more effective in fractured ribs. Can induce nausea and vomiting.

Action of Opioids in the brain

Brain - act on opioid receptors (mu, kappa, delta, sigma) in the limbic system and eliminate the subjective feeling of pain