4.7.2 Opioid analgesics

Equivalent dosages of opioids

Opioids Aware: A resource for patients and healthcare professionals to support prescribing of opioid medicines for pain

Specific dosage instructions should be written on the prescription, i.e. "X to be taken x hourly when required for pain", rather than simply "PRN". This ensures a maximum dose is stated and will prevent dose escalation without prescriber approval.

NPSA Rapid response July 2008: reducing dosing errors with opioid medicines (link) When opioid medicines are prescribed, dispensed or administered, in anything other than acute emergencies, the healthcare practitioner concerned, or their clinical supervisor, should:

  • Confirm any recent opioid dose, formulation, frequency of administration and any other analgesic medicines prescribed for the patient. This may be done for example through discussion with the patient or their representative (exercise care in accepting self-report from patients with dependence or suspected drug dependence), the prescriber or through medication records
  • Ensure where a dose increase is intended, that the calculated dose is safe for the patient (e.g. for oral morphine or oxycodone in adult patients, not normally more than 50% higher than the previous dose)
Choice of opioid

The correct dose of opiate should be found with careful titration of a short acting opiate prior to converting to a slow release formulation of morphine or patch.

All slow release opioids should be prescribed by brand name.

Acute Pain Management

North Devon

  • The NDDH Acute Pain Management Guidelines and NDDH Pain Management in Minor Injury Units Protocol are available on the NDDH Intranet (BOB).

Eastern Devon

  • The Acute Pain Management Strategy for Adult Patients at the RD&E contains very comprehensive advice on the range of pain control techniques available at the RD&E.
  • Where the pain is due to an exacerbation of underlying cancer pain, palliative care guidance should be consulted. If the patient is presenting perioperatively or with pain unrelated to their cancer, the principles outlined in the Acute Pain Strategy should be followed.
Codeine phosphate
  • Tablet 15mg, 30mg, 60mg (£1.10 = 30mg x 28 tablets)
  • Oral solution 25mg in 5ml (£6.46 = 500ml)

Indications

Dose

  • Adult over 18 years, 30–60mg every 4 hours when necessary, to a maximum of 240mg daily

Notes

  1. Codeine is useful for the relief of mild to moderate pain but is too constipating for long-term use.
Diamorphine hydrochloride
  • Injection 5mg, 10mg, 30mg, 100mg, 500mg (£12.65 = 30mg x 5 ampoules)

Indications

Dose

  • Acute pain, by subcutaneous or intramuscular injection, 5mg repeated every 4 hours if necessary (up to 10mg for heavier well-muscled patients); by slow intravenous injection, quarter to half corresponding intramuscular dose
  • Chronic pain, by subcutaneous or intramuscular injection
    • Adult not currently treated with a strong opioid analgesic, initially 2.5–5mg every 4 hours, adjusted according to response
    • Adult, by subcutaneous infusion, not currently treated with a strong opioid analgesic, initially 5–10mg over 24 hours, adjusted according to response
    • Adult currently treated with a strong opioid analgesic, see below for a table of approximate equivalent dosages of opioids
Morphine sulfate
  • Oral solution 10mg/5ml (not a controlled drug) (£5.45 = 300ml)
  • Concentrated oral solution 100mg/5ml (£4.98 = 30ml)
  • Tablets 10mg, 20mg, 50mg (£10.61 = 20mg x 56 tablets)
  • Injection 10mg/1ml, 20mg/ml, 30mg/1ml (£8.84 = 30mg/1ml x 10 ampoules)
  • Suppositories 15mg, 20mg, 30mg (£18.60 = 30mg x 12)
  • Intravenous infusion 50mg/5ml

Indications

Dose

  • Acute pain (adult doses, for children refer to current cBNF)
    • By subcutaneous injection (not suitable for oedematous patients) or by intramuscular injection, initially 10mg (elderly or frail 5mg) every 4 hours or more frequently during titration), adjusted according to response
    • By slow intravenous injection, initially 5mg (reduce dose in elderly or frail) every 4 hours (or more frequently during titration), adjusted according to response
  • Chronic pain, by mouth or by subcutaneous injection (not suitable for oedematous patients) or by intramuscular injection, initially 5–10mg every 4 hours, adjusted according to response

Modified-release 12 hourly oral preparations

Zomorph®
  • m/r capsules 10mg, 30mg, 60mg, 100mg, 200mg (£8.30 = 30mg x 60 capsules)

Indications

  • Modified release opioids (M/R) should only be used for constant, persistent, moderate to severe pain lasting several weeks and unlikely to resolve suddenly
  • Palliative care guidance
  • Licensed for use via gastric or gastronomy tubes (diameter greater than 16FG)

Dose

  • Every 12 hours, dose adjusted according to daily morphine requirements
  • For breakthrough, doses of 1/6 of the total daily dose of M/R opioid given 4-hourly when required. During titration any increase in total daily opioid dosage should not be more than 50% of the previous total daily dosage

Notes

  1. Oral morphine preparations are the first line strong opioid.
  2. Specify dosing interval on prescriptions to avoid confusion e.g. 4 hourly
  3. Zomorph® is the morphine sulphate MR preparation of choice because it is a capsule formulation that may be opened and the contents administered in semi-solid food for patients with swallowing difficulties. MST® lacks these advantages and is more expensive than Zomorph® in the community and hospital and so its use is not recommended
Buprenorphine patches
  • Butec® patch 5 microgram/hour for 7 days (£7.92 = 4 patches)
  • Butec® patch 10 microgram/hour for 7 days (£14.20 = 4 patches)
  • Butec® patch 15 microgram/hour for 7 days (£22.12= 4 patches)
  • Butec® patch 20 microgram/hour for 7 days (£25.86 = 4 patches)

Indications

  • Moderate, non-malignant pain unresponsive to non-opioid analgesics
  • Buprenorphine patches should only be used in patients with cognitive deficit or swallowing difficulties, after a trial of soluble/liquid medication. Remember that Zomorph® capsules can be opened up for ease of swallowing
Dose
  • Initially one '5 micrograms/hour' patch; apply to dry, non-irritated, non-hairy skin on upper torso, removing after 7 days and siting replacement patch on a different area (avoid same area for at least 3 weeks)
Notes
  1. Prescribe buprenorphine patches by brand (Butec®) to ensure continuity. High strength buprenorphine patches (Transtec®) are not approved for use.
  2. Buprenorphine patches are not suitable, or licensed, for use in the management of acute or intermittent pain
  3. Prescribers should ensure that patients and/or their careers are aware that Butec® patches need to be applied at appropriate seven-day intervals to ensure that patients are not left in pain (because of too long an interval) and that the patches are not used wastefully (because of too short an interval). Remember to remove the old patch before application of new patch. To increase the dose, a larger patch should replace the patch that is currently being worn, rather than multiple patches being used
Fentanyl
  • Matrifen® / Mezolar® patch 12 microgram/hour, for 3 days (per patch £1.50 = Matrifen® / Mezolar®)
  • Matrifen® / Mezolar® patch 25 microgram/hour, for 3 days (per patch £2.15 = Matrifen® / Mezolar®)
  • Matrifen® / Mezolar® patch 50 microgram/hour, for 3 days (per patch £4.02 = Matrifen® / Mezolar®)
  • Matrifen® / Mezolar® patch 75 microgram/hour, for 3 days (per patch £5.61 = Matrifen® / Mezolar®)
  • Matrifen® / Mezolar® patch 100 microgram/hour, for 3 day (per patch £6.91 = Matrifen® / Mezolar®)

Indications

  • Severe chronic pain in patients with swallowing difficulties, renal impairment or morphine intolerance

Dose

  • Apply to dry, non-irritated, non-irradiated, non-hairy skin on torso or upper arm, removing after 72 hours and siting replacement patch on a different area (avoid using the same area for several days)
  • Adult and child over 2 years currently treated with a strong opioid analgesic, initial dose based on previous 24-hour opioid requirement

Notes

  1. Prescribers are reminded to prescribe fentanyl by brand to ensure continuity and avoid confusion
  2. Fentanyl patches are available in two distinct types, the reservoir patch and the matrix patch. The formulary choices are Matrifen®, and Mezolar® matrix patches. Whichever brand is chosen, brand name prescribing is essential
  3. Fentanyl patches should not be used for uncontrolled acute pain
  4. Fentanyl patches have a role in those with swallowing impairment, renal impairment and in those intolerant of morphine.
  5. The initial dose of fentanyl should be based on the previous 24 hour opioid analgesic requirement. A conversion scheme from oral morphine to fentanyl patches can be seen in the table of approximate equivalent dosages of opioids, see below
  6. The initial evaluation of the analgesic effect of fentanyl patch should not be made until the patch has been worn for 24 hours due to the gradual increase in serum fentanyl concentration up to this time.
  7. Under no circumstances should a patch be cut
  8. Concomitant use of CYP3A4 inhibitors may lead to potentially dangerous rises in serum fentanyl levels. Examples of CYP3A4 inhibitors include: ketoconazole, itraconazole, clarithromycin, erythromycin, verapamil, diltiazem, and amiodarone
Oxycodone
  • Shortec® capsules 5mg, 10mg, 20mg (£20.58 = 30mg daily)
  • Injection 10mg/ml, 50mg/1ml (£3.20 = 2ml 10mg ampoule)
  • Oral solutionSF 5mg/5ml (£9.71 = 250ml)
  • Modified release 12 hourly dosing
    • Longtec® M/R tablet 5mg, 10mg, 15mg, 20mg, 30mg, 40mg, 60mg, 80mg, 120mg (£25.05 = 40mg daily)

Indications

  • Moderate to severe pain in patients intolerant to morphine

Dose

  • Oral, initially 5mg every 4–6 hours, increased if necessary according to severity of pain, usual maximum 400mg daily, but some patients may require higher doses
  • Slow intravenous injection, 1–10mg every 4 hours when necessary
  • Intravenous infusion, initially 2mg/hour, adjusted according to response
  • Subcutaneous injection, initially 5mg every 4 hours when necessary
  • Subcutaneous infusion, initially 7.5mg/24 hours adjusted according to response
  • Modified release, initially 10mg every 12 hours, increased if necessary according to severity of pain, usual maximum 200mg every 12 hours, but some patients may require higher doses

Notes

  1. Oxycodone cannot be recommended as a replacement for morphine in the step-wise management of pain, but could be considered an alternative for patients who cannot tolerate morphine
  2. In primary care for oxycodone modified release please prescribe the brand Longtec® as this is more cost effective.
  3. In primary care for oxycodone standard release please prescribe the brand Shortec® as this is more cost effective.
Tramadol
  • Capsules 50mg (£3.70 = 100 capsules)
  • Injection 50mg/ml (£0.98 = 2ml ampoule)

Indications

  • Moderate pain

Dose

  • Oral, 50–100mg not more often than every 4 hours; total of more than 400mg daily not usually required
  • By intramuscular injection or by intravenous injection (over 2–3 minutes) or by intravenous infusion, 50–100mg every 4–6 hours
  • Postoperative pain, 100mg initially then 50mg every 10–20 minutes if necessary during first hour to total maximum 250mg (including initial dose) in first hour, then 50–100mg every 4–6 hours; maximum 600mg daily

Notes

  1. Modified-release preparations of tramadol are non-formulary. However, if there is a defined clinical need for a modified-release preparation, prescribe as 12-hourly brand product Marol® to ensure lowest acquisition cost.
  2. Tramadol may be useful if codeine is ineffective or not tolerated. Up to 20% of patients may not metabolise codeine efficiently to its active metabolite, morphine.
Abstral®
  • Sublingual fentanyl tablets 100 micrograms, 200 micrograms, 300 micrograms, 400 micrograms, 600 micrograms, 800 micrograms (£5.00 = per tablet)

Indications

  • Breakthrough chronic cancer pain not adequately treated with additional oral morphine

Dose

  • Abstral® requires dose titration to determine optimal dosage- consult product literature for further details.

Notes

  1. Abstral® is not dose equivalent to the other oramucosal fentanyl products available (Actiq® and Effentora®) and patients must not have their preparations switched.
  2. Immediate release oral morphine remains the preferred treatment for breakthrough pain. When more rapid onset and briefer duration of action are of significant clinical importance the greater cost of sublingual fentanyl citrate (Abstral®) may be justified.
Tapentadol
  • Modified release tablets 50mg, 100mg, 150mg, 200mg, 250mg (£99.64 = 200mg x 56 tablets)

Indications

  • Severe pain in patients with morphine intolerance

Dose

  • Modified release, initially 50mg every 12 hours, adjusted according to response; maximum 500mg daily

Notes

  1. Secondary care initiation only
  2. Tapentadol prolonged-release tablets are a treatment option for patients intolerant to morphine and may cause less GI adverse effects than other strong opioid analgesics
  3. Tapentadol is a new opioid analgesic with noradrenaline reuptake inhibitor properties. Tapentadol should only be initiated in secondary care by a pain specialist or rheumatologist.
  4. Immediate-release tapentadol is not included in the Joint Formulary
  5. The equianalgesic dose ratio of tapentadol to morphine is 2.5:1, and to oxycodone is 5:1. These ratios reflect analgesic efficacy and not opioid activity. Since a proportion of tapentadol's analgesic activity comes noradrenaline reuptake inhibition there is a risk of opioid withdrawal problems if a direct switch is made from morphine or oxycodone. To avoid such problems local specialists recommend adding a dose of tapentadol to the patient's existing regimen, followed by a gradual reduction of opioid medication over at least two weeks

 

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