|
|
Morphine |
Tramadol |
|
Receptor targets |
Agonist M:K:D = 3:1:1 |
+Tramadol: MOP and 5HT -Tramadol: NAd
|
|
Mu receptor activity |
Full agonist |
Partial agonist; ceiling effect |
|
Naloxone reversal |
100% |
30% only! |
|
Active metabolite |
M6G (10%): 14x more active M3G (70%): neurotoxic (cognitive dysfunction, seizures) |
+M1: MOP only -M1: NAd Note M1 4x more potent at M1 |
|
Equipotent doses |
15mg PO 5mg IV |
100mg PO |
|
Effect of polymorphism: |
Rarely significant |
↑2D6 activity: ↑MOP, ↓5HT effects ↓2D6 activity: ↓MOP, ↑5HT effects |
|
|
Morphine |
Tramadol |
|
Analgesia use: |
Acute somatic Acute visceral |
Acute somatic Acute visceral Acute and chronic neuropathic, phantom |
|
Sedation |
Y++ |
Y+ |
|
Miosis |
Y++ |
Y+ |
|
Euphoria, dysphoria |
Y++ |
Y+ |
|
Hallucinations |
Y+ |
Y+ |
|
Tolerance, dependence, addiction |
Y++ |
Rare |
|
Seizures |
If renal failure -> M3G accumulation |
Lowers seizure threshold |
|
Serotonin syndrome |
N |
If combined with MAO inhibitor, less likely SSRI |
|
|
Morphine |
Tramadol |
|
HR, SVR, mAP |
↑PSNS output, ↓SNS output, ↓baroreceptor reflex ↓HR, ↓SVR, postural ↓mAP Histamine release -> ↓SVR |
↑SNS output (examiner says) |
|
|
Morphine |
Tramadol |
|
Resp centre depression ↓RR, ↓TV R shift ↓slope MV-PaCO2++ L shift ↓slope MV-PaO2 + |
Y++ |
Y+ |
|
|
Morphine |
Tramadol |
|
Constipation (↓Motility, ↑sphincter tone) |
Y ++ |
Y + |
|
Nausea, vomiting |
Y+ |
Y++ Antagonises 5-HT3 antagonists |
|
Urinary retention |
Y |
N |
|
Ureteric spasm |
Y |
N |
|
↓ADH, ↓ACTH, ↓GnRH |
Y |
? |
|
Histamine release |
Y |
N |
|
Immune suppression |
Y |
? |
Feedback welcome at ketaminenightmares@gmail.com