Pain management

Question 1

Describe the clinical pharmacology of paracetomol?

Answer 1

Analgesic and anti pyrexial effects. Has a synergistic effect with codeine.

Method of action is unknown.

Available in many different formulations.

Causes irreversible liver damage in overdose.

Question 2

Describe the clinical pharmacology of NSAIDs?

Answer 2

COX inhibitors.
COX 1: produce GI protective prostoglandins
COX 2: produces leukotrienes which are involved in pain and inflammation.

Beneficial effects:
Anti-inflammatory and analgesic effect

Adverse effect:
2nd biggest cause of peptic ulceration

Question 3

Describe the clinical pharmacology of opioids and give examples of weak and strong opioids?

Answer 3

Block the opioid receptors in the central and peripheral nervous system and the GI tract (s/e=constipation).

Weak opioids:
Codeine
Dihyrocodeine
Tramadol

Most effective when used in combination with paracetomol.

Strong opioids:
Morphine
Diamorphine
Buprenorphine
Oxycodone
Fentanyl

Cause side effects of:
Drowsiness
Constipation
Sedation

In strong opiates can cause:
Hypotension
Respiratory depression
Urinary retention

Come in many different formulations.

Question 4

Describe the management of neuropathic pain?

Answer 4

Tricyclic antidepressants.

Anticonvulsants:

• Carbamazepine
• Gabapentin
• Pregabalin

Question 5

Discuss the WHO pain ladder?

Answer 5

Step 1: Non-opioids
Step 2: Weak opioid +/- non opioids
Step 3: Strong opioids for severe/moderate pain +/- non opioids