Guidelines on Commencing Morphine

Starting dose

Side effects

Increasing dose

Review patient regularly

Breakthrough doses

Converting to slow release opioid

When a patient needs to start on a strong opioid, it is usual to commence oral morphine. Morphine syrup has the advantage of allowing review of the dose every four hours, and is thus better than slow release morphine to achieve rapid control of pain (and to reduce the dose if side-effects occur). Consider starting with slow release morphine in situations where there are too few nurses to administer morphine every 4 hours. 

Starting dose

• Morphine syrup 2.5 – 10mg 4-hourly. 
  • 10mg 4-hourly 
  • 2.5 – 5mg 4-hourly elderly, cachectic, Patients who are HIV positive also respond well to low dose morphine syrup 

Anticipate side effects routinely

• Constipation: 
  • Lactulose 15 – 30ml daily and
  • Senekot 2-4 tabs daily or
  • Milk of Magnesia/Liquid Paraffin (3:1) 15 – 30ml daily 
• Nausea: 
  • Haloperidol 1.5mg – 5mg nocté for five to seven days or
  • Metoclopramide 10mg tds for five to seven days. 
• Confusion/Drowsiness: is a temporary side effect and usually wears off after a few days. 

Increasing dose 

• if pain persists or recurs increase the dose of morphine in increments of 30-50 percent of current dose., eg  5 mg →10 mg → 15 mg →20 mg →30 mg → 45 mg → 60 mg → 90/100 mg→120/160 mg 
• There is no ceiling (maximum) dose of morphine. The dose of morphine is titrated to the patient’s pain control requirement. Respiratory depression does not occur with careful titration of morphine dose administered orally or by continuous subcutaneous infusion.

Review patient regularly 

• Severe pain: dose can be increased twice a day. If less severe, increase every one or two days to minimise side-effects. 
• Once tolerant, a double dose can be given at bedtime to avoid waking for 2 am dose. (not evidence-based) 
• Consider converting to slow release opioid once pain controlled for ease of administration. 

Breakthrough doses 

• Breakthrough doses may be used when pain is not controlled on the regular dosing schedule (e.g. a patient on morphine syrup 20mg 4-hourly will receive 10-20mg morphine syrup stat). 
• Use 50 – 100 percent 4-hourly dose (e.g. a patient on morphine syrup 20mg 4-hourly will receive 10-20mg morphine syrup stat). 
• Consider increasing morphine dose if more than two breakthrough doses in previous 24-hours. 
• To increase the morphine dose add previous 24-hour use of morphine of regular and breakthrough doses and divide into new dose. 
• Divide 24-hour dose accordingly for oral syrup 4 hourly (divide by 6) /slow release morphine administered 12 hourly (divide by 2) /subcutaneous doses (continuous subcutaneous infusion – total dose over 24hr period). 

Converting to slow release opioid 

• For 12 hourly dosing, calculate the 24-hour dose of syrup and divide into two bd doses. 
• Give the last dose of syrup together with first dose of slow release morphine to cover the few hours until slow release absorption has built up. 
• Continue to give morphine syrup for breakthrough pain. A dose of morphine syrup of 50 – 100% of the 4-hourly doe equivalent may be taken for breakthrough pain. 
• Remember to increase the dose of prn oral morphine proportionally if the dose of slow release morphine is increased.