21 st June BDS BASHD Therapeutics Pain and Analgesia. BASHD Therapeutics Analgesics and Pain Management. Links to other BASHD content

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1 Volume of Prescribing by Dentists 2011 ( a reminder) BASHD Therapeutics Analgesics and Pain Management Analgesics account for 1 in 80 dental prescriptions made A lot more analgesics will be suggested for OTC use Dr Jamie Coleman Senior Lecturer in Clinical Pharmacology NIC = Net Ingredient Cost Information from NHS Information Centre Learning Objectives Links to other BASHD content The Practical Application and Use of Medicines with Reference to Dentistry By the end of this session (and additional reading) you should be able to: Distinguish and describe the common analgesics prescribed in dentistry Discuss key factors that influence the choice of analgesic, its dosage and route of administration Detail treatment options for dental pain using guidelines where appropriate Outline adverse drug reactions and drug interactions Surgery Pain and pain control - principles of analgesic therapy Pharmacology Non steroidal antiinflammatory drugs (NSAIDs); Antiinflammatory steroids; Sedative and anxiolytic drugs; Antidepressant drugs Definition of Pain PAIN "An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage" International Association for the Study of Pain Dr Jamie Coleman 1

2 Types of Pain Pain is a symptom A Patient s description may point towards the type of pain This can help diagnosis and treatment NOCICEPTIVE Caused by stimulation of peripheral nerve fibres responding to stimuli approaching or exceeding harmful intensity NEUROPATHIC Caused by damage or disease affecting the nervous system involved in bodily feelings PSYCHOGENIC No apparent organic basis Targets for Pain Control Possible targets: source of pain nociceptive substances nerve transmitter substances modulators in spinal cord and brain emotional reaction to pain Treating Pain (1) WHO Pain Ladder Analgesics are used in dental care as a temporary measure until causative factors have been brought under control Holistic care requires explanation, reassurance, sometimes local measures and occasionally a prescription! Pain persisting, move up one step Signs of toxicity or severe side-effects, reduce dose or move down one step Treating Pain (2) Assess the type and intensity of pain Start at an appropriate level on the ladder for the patient s situation Consider adjuvant analgesics at all stages Bear in mind any contraindications, cautions and interactions (i.e. Overall suitability for patient) Titrate up or down as required Treating Pain (3) Principles of good pharmacological control post-procedure Post-op taking analgesics before LA has worn off can improve pain control Regular administration times (e.g. every 6 hours) will reduce breakthrough pain Later in the course PRN (as required) treatment may be suitable as patients requirements diminish Dr Jamie Coleman 2

3 ANALGESIC AGENTS Use your local guidelines Efficacy of different agents Many original trials of analgesics used relief of dental pain as the outcome measure Trials show that weak opioids may be less effective for odontogenic pain Derry et al. BDJ 2011; 211: Paracetamol - the facts Analgesic actions (? Mechanism inhibits prostaglandins in CNS) Additional antipyretic action helpful in some dental conditions NO anti-inflammatory action Minimal interactions / adverse effects Suitable for children (in correct dosage) Uses: - Mild / Moderate pain (alone) - Moderate / Severe pain in combination therapy Paracetamol Dosing (mild to moderate dental pain) Adult Dosage (> 50 kg body weight) Paracetamol tablets 500 mg 2 tablets (1 g) to be taken every 4 6 hours (Maximum 8 tablets daily) Do not exceed recommended daily dose Treatment usually for up to 5 s Consider 1 tablet every 4 6 hours in adults with a low body weight (<50 kg) Paracetamol Dosing (mild to moderate dental pain) Dosing for children (Age Banding) Paracetamol Soluble Tablets 500 mg Paracetamol Suspension 120 mg/5 ml or 250 mg/5 ml Always consult the BNFc Age Band 6 months 2 years Dose 120 mg four times a 2 4 years 180 mg four times a 4 6 years 240 mg four times a 6 8 years 250 mg four times a 8 10 years 375 mg four times a years 500 mg four times a years 750 mg four times a Dr Jamie Coleman 3

4 NSAIDs - the facts Inhibitors of prostaglandin synthetase (cyclooxygenase) OFF target COX 1 - constitutive response protects gastric mucosa ON target COX 2 - inducible response inflammatory, also renal Anti-inflammatory activity leads to pain relief GI side-effects common NSAIDs the practice Most odontogenic pain can be relieved by NSAIDs Particularly good for dental pain of inflammatory origin (e.g. pulpitis) NSAIDs used for dental practice include ibuprofen, diclofenac and aspirin (Aspirin may be less appropriate due to risk of bleeding following dental extraction or other minor surgery) Ibuprofen Dosing (mild to moderate dental, post-op or inflammatory pain) Dosing in adults Ibuprofen Tablets 400 mg 1 tablet to be taken four times a (preferably after food) can be increased, if necessary, to a maximum daily dose 2.4 g (i.e. 800 mg three times a ) maintenance total daily dose of 600 mg to 1.2 g may be adequate Ibuprofen Dosing (mild to moderate dental, post-op or inflammatory pain) Dosing for children (Age Banding) Ibuprofen tablets 200 mg Ibuprofen Suspension 100 mg/5 ml Always consult the BNFc Age Band 6 months 1 year Dose 50 mg four times a 1 4 years 100 mg three times a 4 7 years 150 mg three times a 7 10 years 200 mg three times a years 300 mg three times daily years mg four times a Diclofenac Dosing (moderate inflammatory or post-op pain) Adult Doses Diclofenac Sodium Tablets 50 mg 1 tablet to be taken three times a (preferably after food) Do not exceed recommended daily dose (150 mg/) Sustained release preparations are available (not for NHS dental use) Not recommended in children NSAIDs - Drug-drug Interactions Main issue is the risk of bleeding: Potentiated by antiplatelets and anticoagulants (even low dose aspirin) Increased risk of bleeding with SSRIs Dr Jamie Coleman 4

5 NSAIDs - Adverse effects Preventing NSAID problems (1) Renal dysfunction Gastrointestinal side- Effects Gastritis, bleeding NSAID-induced erosive gastritis Hypersensitivity reactions rashes, angioedema, bronchospasm Prescribe NSAIDs associated with a lower risk (e.g. ibuprofen) Start at lowest recommend dose Do not use more than one NSAID Avoid in patients with previous hypersensitivity to aspirin or any other NSAID (including those in whom attacks of asthma have been precipitated by aspirin) Preventing NSAID problems (2) Weak Opioids In patients with history of previous or active peptic ulcer disease who require an NSAID: Prescribe a Proton Pump Inhibitor (PPI) e.g. Lansoprazole 15 mg to be taken once daily during NSAID treatment e.g. Dihydrocodeine, Codeine Phosphate Opioids act on the CNS to alter the perception of pain but have no antiinflammatory properties Used for moderate to severe pain Relatively ineffective in dental pain Adverse effects can be unpleasant (e.g. nausea, constipation) Weak Opioids Dosing (moderate pain but less suitable for dental pain) Dosing in adults Dihydrocodeine 30 mg tablets 1 tablet to be taken four times a (maximum 240 mg daily) Codeine Phosphate 30 mg tablets 1 to 2 tablets to be taken four times a (max 240 mg daily) (Both can also be given intramuscular but this is not recommended see BNF) Combination Agents Paracetamol and NSAIDs act through mechanisms different to opioids NSAID-opioid or paracetamol-opioid combinations act synergistically to produce analgesic action Problems with combination agents include: Reduction of scope to titrate individual components Increased risk of side-effects with low dose combinations (e.g. co-codamol 8/500) without a significant additional relief of pain Increased danger from overdose Dr Jamie Coleman 5

6 Different Analgesic Combination Drugs Name Combination of: Usual Adult Dose Co-codamol Codeine phosphate Paracetamol 1 2 tablets every 4 6 (8, 15 or 30 mg) (500 mg) hours; max 8 tablets daily Co-dydramol Dihydrocodeine Paracetamol 1 2 tablets every 4 6 (10, 20 or 30 mg) (500 mg) hours; max 8 tablets daily Co-codaprin Codeine phosphate Aspirin 1 2 tablets every 4 6 (8 mg) (400 mg) hours; max 8 tablets daily Tramacet Tramadol (37.5 mg) Paracetamol (375 mg) 2 tablets not more that every 6 hours Codafen Continus Codeine phosphate (20 mg) Ibuprofen (M/R) 300 mg 1 2 tablets every 12 hours; max 6 tablets daily Approved name is followed by two doses separated by a / to indicate the dose of each component e.g. Co-dydramol 20/500 has 20 mg of dihydrocodeine and 500 mg paracetamol in each tablet Tramadol Opioid analgesic & enhanced 5HT and adrenergic pathways Indicated for moderate to severe pain (postoperative hosp) Side-effects: N&V, drowsiness, respiratory depression, hypotension Adult Dose: mg every 4 hours Usual maximum daily dose 400 mg Strong Opioids Strong Opioids useful for severe postoperative pain Generally not required in general dental practice Many different agents: morphine (most widely used) fentanyl oxycodone pethidine Strong Opioids (2) Act on Mu and Kappa receptors in the CNS Many different formulations tablets / syrup / subcutaneous / IV injection Analgesic / euphoria / sedation Repeat use associated with dependence Avoid in respiratory depression, hypotension and in liver impairment Strong Opioids Dosing (Severe pain) Dosing in adults Pethidine 50 mg tablets Orally: mg every 4 hours Maximum daily dose of 450 mg Metabolised to norpethidine (which can accumulate in renal impairment) Can stimulate the CNS and cause seizures Patient-controlled analgesia Delivers boluses of opioid analgesia Dedicated delivery device Careful settings bolus dose control, time limit control, overrides Allow better control of pain especially following major surgery (e.g. MaxFax Ca surgery) Dr Jamie Coleman 6

7 Adjuvant Agents Included at every step of the ladder as additional consideration for treatment of pain Includes certain Antiepileptic / Antidepressant agents Act as centrally acting analgesics Generally used at lower doses than their usual indications Drug responses to such agents varies from patient to patient Tricyclic Antidepressants e.g. amitriptyline, dosulepin Antiepileptic agents e.g. pregabalin, gabapentin, carbamazepine Anxiolytics e.g. diazepam Tricyclic Antidepressants (Atypical Facial Pain) Amitriptyline (unlicensed for neuropathic pain) 10mg daily at night Gradually increased to 75mg daily Adverse effects: sedation/ drowsiness, antimuscarinic effects (dry mouth, urinary retention) Cautions: dangerous in overdose Alternatives include: nortriptyline (less sedative), dosulepin Antiepileptics (Trigeminal Neuralgia) Gabapentin 300mg three times a Increased gradually according to response to 3.6 grams maximum daily dose Carbamazepine 100mg one to two times a Increased according to response to 1.6 grams maximum daily dose Usual dose 200mg three to four times daily Requires monitoring blood tests (GP) Various drug-drug interactions Anxiolytics (Adjuvant in various conditions including facial pain) Benzodiazepines (e.g. diazepam) may provide adjuvant therapy in pain disorders Used in lower doses than those given for hypnotic (sedative) use May also provide additional muscle relaxation Diazepam tablets 2mg 1 tablet up to three times daily Short courses only recommended, susceptible to abuse Chronic oral and facial pain Acute problems affecting the mucosa Includes a variety of distinct diagnostic entities Persistent Idiopathic Facial Pain ( Atypical facial pain ) Temporomandibular dysfunction May call for prolonged use of analgesics / adjuvant agent treatment Often requires specialist referral and psychological support (as well as drugs) E.g. Tricyclic antidepressants such as amitriptyline Various painful mucosal conditions acute herpetic gingivostomatitis, apthous ulceration, erythema multiforme Pain may be better treated topically Benzydamine Hydrochloride 0.15% oral rinse or spray 15mls or 4-8 sprays used every 1.5 to 3 hours Occasionally causes numbness or stinging, rarely causes hypersensitivity Dr Jamie Coleman 7

8 Special Circumstances: Opioid Dependence Is generally irrelevant in: terminal care acute pain Only relevant if addicts try to persuade you to prescribe (self-inflicted injury, refuses surgical intervention, allergies to simple analgesia / NSAIDs) BEWARE! Special Circumstances: Liver / Kidney Disease See special circumstances in prescribing in other lecture Liver disease Risk of bleeding increased NSAIDs Caution with Paracetamol (regular, high doses) Opioids may be slowly metabolised and precipitate encephalopathy in liver failure Renal Disease NSAIDs may further increase renal impairment Elimination of some drugs decreased lower doses required Special Circumstances: Children Choice of analgesic based on suitability for the condition and the child Usually NSAIDs (not aspirin) / Paracetamol suitable Prescribe by weight or age banding (see individual drugs) Dosing errors are common double check DO NOT prescribe aspirin to children (<16yrs) risk of Reye s syndrome Sugar-free medicines should be provided where possible Summary Pain and analgesia take a good pain history make a diagnosis analgesia used as temporary measure until causative factors controlled decide which agents will help give in effective doses & frequency adjust the dose according to the patient's view of efficacy Any Questions? Dr Jamie Coleman 8