What is the order of the pain ladder?
1) Non-opioids - Paracetamol & NSAIDs
2) Weak opioids - Codeine & tramadol
3) Strong opioids - Morphine, oxycodone, methadone
4) Very strong opioids - Fentanyl, Dihydrocodeine
What is the MOA of weak opioids?
Codeine & Tramadol
- Weak µ-receptor agonist
- Tramadol also acts as a SNRI using the serotonergic and adrenergic pathways
Side effects of weak opioids?
- Constipation
- Urinary retention
- drowsiness
- neurological and respiratory distress (overdose)
Warnings of weak opioids?
- Tramadol reduces the seizure threshold - also increased risk of serotonin syndrome
- Epilepsy
- Renal & hepatic impairment
- Elderly
- Codeine and dihydrocodeine can never be given IV - increases risk of anaphylaxis like reaction
What are some interactions of opioids
- Other sedating drugs e.g antipsychotics, benzodiazepines, tricyclic antidepressants
What is a specific interaction of tramadol?
- Drugs that also reduce the seizure threshold e.g antipsychotics
- Serotonergic drugs e.g - SSRI and tricyclic antidepressant
What commutation should you give a patient taking a weak opioid?
- May cause constipation - take a stimulant laxative (senna)
- Do not drive or operate heavy machinery
What is the treatment pathway for epilepsy?
1) Carbamazepine
2) Valporate, lamotrigine e.t.c
3) Gabapentin, pregabalin e.t.c
What drug can be used to treat serotonin syndrome?
1) Cyproheptadine - It is a serotonin antagonist
2) Benzodiazepines - muscle relaxants
