Management of severe pain

 

 

Buprenorphine

• partial agonist at mu opioid receptors giving powerful relief

  from pain and has less analgesic tolerance. constipation, cognitive

  impairment, mild withdrawal or dependence than other mu agonists. 

• Available preparations include sublingually (200-400mcg every 6-8 hours), skin patches (initially 5mcg/hour removing after 7 days for non-malignant pain or 35mcg/hour in moderate/severe pain) or injection (300-600mcg every6-8 hours) 

• Buprenorphine also has a ceiling effect on

  respiratory depression which is different to the other opioids i.e. with increasing

  dose the respiratory depression only increases to a certain point but the analgesic

  effect is not affected i.e. analgesia continues to rise with increasing dose. 

 

 Fentanyl

• Fentanyl is highly potent binding mainly at the mu receptor with rapid onset of

  action but only for a short duration.

•  Indicated in where there is stable pain and in breakthrough pain.

• Parenteral fentanyl is 80 times more potent than parenteral morphine.

• Dosage; Transdermal 12 or 25mcg/hour removing after 72 hours.  Transdermal fentanyl does not peak in concentration until 8-12 hours after administration so analgesic should be provided to give pain relief during this period. Other formulations include buccal,sublingual and nasal sprays. 

 

 Hydromorphone

• 7.5 times more potent than morphine (1.3mg hydromorphone

  and 10mg morphine) and

•  An oral bioavailability of 30-40% and  used as 3rd or 4th

  line in the treatment of moderate to severe pain where the patient is unable to

  tolerate morphine or oxycodone.

• The usual oral dose is 1.3mg every 4 hours (immediate release) or 4mg

  every 12 hours for the modified release.