Community pharmacy Topic 9: Pain control Headache Management Pyrexia or Fever

1. Community pharmacy Topic 9:Pain controlHeadache ManagementPyrexia or Fever

2. Background • Pain is an uncomfortable experience that occurs as a result of tissue damage and which has an emotional dimension in addition to the physical damage. • The extent to which the same level of pain interferes with the emotional dimension and with a patient’s lifestyle varies from one individual to another due to variation in the pain threshold.

3. Types of pain • Nociceptivepain: arising from pain receptors (e.g. twisted ankle) • Neuropathic pain: arising from nervous system (e.g. trigeminal neuralgia, shingles) • Pain with no apparent cause.

6. The endogenous analgesia system • Endogenous peptide agonists, such as enkephalins and endomorphins, act on opioid receptors which present as: • receptor: agonist effect causes analgesia at supraspinal level, euphoria, respiratory depression, dependence • receptor: analgesia at spinal level, miosis, sedation • receptor: dysphoria, hallucination.

8. Examples of painful conditions • Headache: tension headache, migraine, sinus headache • Gingival pain • Myalgia, arthralgia • Traumatic pain • Cancer pain. • Menstrual and post-partum pains • All pains of rheumatological conditions

9. Assessment of pain • Psychosocial assessment: impact of pain on psychological well-being and social activities • Medication history: analgesics used and outcome • Assessment of previous pain problems: history of pain problems • Factors that influence pain: activities that increase or decrease occurrence of pain

10. Qualitative analysis using visual analogue: patient can describe quantitatively the impact of pain • Measurement instruments: to evaluate impact of pain on patient’s physical and psychological wellbeing • Diaries: to identify activities that may relate to the occurrence or deterioration of the condition.

12. Pain management • Analgesics • Acupuncture and massage • Neurosurgery or neurolytic nerve block • Physical therapy • Psychological techniques. Mild pain: paracetamol, NSAIDs Moderate pain: paracetamol, NSAIDs, codeine Severe pain: strong opioid drugs (e.g. morphine).

13. Analgesic drugs • Opioid and non-opioid analgesic drugs are commonly used

14. Paracetamol • This is an antipyretic with analgesic properties • Dosage forms: tablets (500 mg), soluble tablets (500 mg), oral suspension (125 mg/5 mL, 250 mg/5 mL), suppositories (125 mg, 250 mg, 500 mg) • Dosage: adults: 0.5–1 g every 4–6 hours to a maximum of 4 g daily; children: every 4–6 hours up to a maximum of 4 doses in 24 hours:

15. 3 months–1 year 60–120 mg • 1–5 years 120–250 mg • 6–12 years 250–500 mg • Cautions: hepatic impairment, renal impairment, alcohol dependence • Over dosage: hepatotoxicity • In over dosage, the quinone reacts with cellular proteins and nucleic acid in the liver.

16. Compound analgesics • These contain a non-opioid drug with an opioid component (e.g. co-codamol is paracetamol and codeine). • A number of cold preparations contain paracetamol. Advise patients using cold preparations that contain paracetamol against the concomitant use of paracetamol to avoid overdosage.

17. Non-steroidal anti-inflammatory agents • Aspirin: • Has analgesic, antipyretic and anti-inflammatory actions; the anti-inflammatory action is experienced at high doses when side-effects are more common. • It inhibits cyclo-oxygenase, resulting in decreased release of prostaglandins, and has an antiplatelet effect, irreversibly inhibiting cyclooxygenase in platelets and preventing formation of thromboxane A2 (platelet aggregation agent).

18. Dosage forms: tablets, dispersible tablets (300 mg), low-dose aspirin tablets (75 mg) • Indications: headache, transient musculoskeletal pain, dysmenorrhoea, pyrexia; low-dose: prophylaxis of cerebrovascular disease and myocardial infarction • Dosage regimen: maximum adult daily dose 4 g daily (300–900 mg every 4–6 hours) • Side-effects: gastrointestinal disturbances (irritation, blood loss, peptic ulceration), increased bleeding time, bronchospasm

19. Cautionary labels: take after food, use enteric coated tablets to decrease physical damage during drug administration. • Contraindications: children (occurrence of Reye’s syndrome – fatty liver degeneration accompanied by encephalopathy), haemophilia and bleeding disorders, acute or history of peptic ulcers • Cautions: asthma, allergic disease, the elderly, hepatic and renal impairment, pregnancy

20. Pregnancy: during the third trimester use of aspirin may present potential bleeding disorders in mother and fetus, delayed onset and increased duration of labour with increased blood loss • Drug interactions: enhanced anticoagulant effect of warfarin

22. NSAIDs – selective inhibitors of cyclooxygenase 2 • Improve gastrointestinal tolerance • Indicated for symptomatic relief in osteoarthritis and rheumatoid arthritis in patients at high risk of developing a gastroduodenal ulcer • Not to be used as routine treatment • Contraindications/cautions: in congestive heart failure, hypertension, oedema • Example: celecoxib.

23. Opioid analgesics • Morphine : the standard drug against which other opioids are compared • Diamorphine (heroin): more potent • Codeine : higher bioavailability than morphine but less potent • Tramadol: presents fewer of the typical opioid side-effects.

24. Effects • Analgesia (elevate pain threshold, alter reaction to pain) • Euphoria (relieve anxiety and fright) • Sedation (induce sleep) • Reduce gut motility (control diarrhoea) • Control cough (cough suppression)

25. Side-effects • Psychological and physical dependence • Respiratory depression • Nausea and vomiting • Constipation. • Contraindications: respiratory disease, head injury, raised intracranial pressure. • Opioids can cause respiratory depression. They should be avoided in patients with acute respiratory insufficiency, sputum retention, bronchiectasis and chronic bronchitis.

26. Morphine • Used in chronic, severe pain in advanced cancer and in post-operative pain • Has a central analgesic action, produces euphoria and a sense of detachment, all of which could be useful in advanced cancer and in palliative care • Duration of action is of about 7 hours • May cause drowsiness, aggravation of gastrointestinal pain

27. Administration: – normal release morphine elixir: effect within 20 minutes, peak 60 minutes – modified-release tablets: peak 4–8 hours – injections: considered when patient presents with persistent nausea and vomiting, difficulty in swallowing and when patient is not cooperative.

28. Fentanyl • Used for intra-operative analgesia but is not suitable for post-operative analgesia since the duration of action is short • For long-term analgesia, transdermal patches may be preferred • Remifentanil: has a rapid onset of action (2 minutes) and a short duration of action.

29. In patients receiving opioid analgesics, prophylaxis for nausea and vomiting should be considered using antiemetics and when opioid is being used long term consider a laxative such as lactulose due to incidence of constipation as a side-effect. Opioids can cause confusion, especially in older patients.

30. Guidelines for analgesia • Nociceptor-generated pain: follow the analgesic ladder • Neuropathic pain: include use of adjuvant analgesics such as anticonvulsants (e.g. carbamezepine), antidepressants (e.g. imipramine) and others (e.g. baclofen) • Unknown cause: opioids with adjuvant analgesics such as anticonvulsants, antidepressants.

33. Special techniques • Neural blockade • This involves the injection of local anaesthetic close to the sensory area where the pain is occurring so as to block conduction of pain impulses. The use of adrenaline in combination with the local anaesthetic is considered to increase duration of action of the anaesthetic due to the vasoconstriction that occurs.

34. Patient-controlled analgesia (PCA) • An opioid drug is delivered in a pump system which delivers a pre-set dose on activation. A safety feature (lock-out time) ensures that the patient does not reactivate and get release of drug immediately after an activation. The pump delivers the drug by subcutaneous injection. It gives the patient a feeling of control over pain management and results in individual dosing.

35. Local anaesthetics • Concomitant administration of a vasoconstrictor (e.g. adrenaline) to increase duration of action may be considered. Such practice is contraindicated if the anaesthetic is being used near extremities, due to ensuing vasoconstriction.

36. Management of selected painsyndromes • Dysmenorrhoea: use of oral contraceptive agents when menstrual cycle disorders are associated with clinical dysmenorrhoea • Trigeminal neuralgia: characterised by abrupt, intense bursts of pain along one side of the face. Carbamazepine and phenytoin may be considered during the acute phase

37. • Herpetic and postherpetic neuralgia: postherpetic neuralgia may persist for a number of months. Antiviral agents are used during the herpetic phase and amitriptyline and gabapentin may be considered in the postherpetic phase • Post-amputation and phantom limb pain: antidepressants are considered.

38. Transcutaneous electrical nerve stimulation (TENS) • Used for chronic pain • Consists of a small, battery-operated instrument that delivers rapid pulses of a small electric current to electrodes applied to the skin • Provides relief and is indicated within a pain management programme.

39. Headache and migraine Management

40. Classification of headache • Primary headache disorders (e.g. muscle contraction headache, vascular headache) • Psychogenic disorders • Secondary headache disorders (e.g. sinus • headache).

41. Assessing headache attacks • Time of day when attacks occur • Duration of attack • Intensity of pain • Location of pain • Precipitating factors (e.g. food, activities) • Factors that relieve or improve headache • Concomitant phenomena • Significance to patient – impact on lifestyle.

42. Sinus headache • Presentation: localised to the periorbital area or forehead; blowing the nose intensifies pain • Possible cause: infection or blockage of the paranasal sinuses • Duration: several days or more • Onset: gradual • Management: analgesics and nasal decongestants

43. Muscle contraction (tension) headache • Presentation: bilateral, diffuse pain often over the top of the head • Possible cause: tight muscles in the upper back, neck • Duration: up to several days • Onset: gradual • Management: acute: analgesics; chronic: relaxation, short-term benzodiazepines, antidepressants.

44. Vascular headache (migraine) • Presentation: recurrent hemicranial, throbbing headache, nausea, vomiting • Possible cause: distension or dilatation of intracranial arteries or traction or displacement of large intracranial veins • Duration: aura 30 minutes before onset of attack; several days • Onset: acute • Management: NSAIDs, compound analgesics, 5HT1 agonists.

45. Migraine-precipitating factors • Psychological factors: stress, personality • Environmental factors: noise, light, disturbed sleep patterns • Physiological factors: epilepsy, allergy, hypoglycaemia • Dietary factors: cheese, alcohol, caffeine withdrawal or excessive caffeine intake • Iatrogenic factors • Drugs: ethinylestradiol, indometacin, H2-receptor antagonists.

46. Management of migraine • Acute treatment: analgesics or 5HT1 agonist metoclopramide (if accompanied by nausea) • Prophylaxis: beta-blockers (e.g. propranolol), calcium channel blockers, tricyclic antidepressants (e.g. amitriptyline), pizotifen, anticonvulsants (e.g. valproate, topiramate).

47. 5HT1 agonists • Examples: sumatriptan, zolmitriptan • Considerable value in acute migraine attack inpatients who fail to respond to conventional analgesics • Caution: pre-existing cardiac disease (angina, hypertension, transient ischaemic attacks, stroke) since they cause vasoconstriction, hepatic impairment • Side-effects: tingling sensations, numbness, dizziness, vertigo • Patient education: report occurrence of severe tightness.

48. Headache in childhood • Occurs commonly: by age 7 years 40% of children experienced headaches and by age 15 years 75% of individuals would have experienced headaches. • Before adoloscence headache is mainly migraine and with adoloscence pattern changes to muscle contraction headache.

49. Medication overuse headache (MOH) • Rebound patterns of headache from repeated use of symptomatic headache medications (analgesics, ergot alkaloids, triptans) • Most frequent secondary cause of chronic daily headache (headache for 4 hours on 15 days/ month) • Diagnosis: detailed patient drug history and medication use • Withdrawal of MOH-inducing medication • High occurrence with combination analgesics containing caffeine and with triptans.

50. Pyrexia Or Fever