[Verse 1]
Mu receptors run the show, that's the primary gate
Delta, kappa, nociceptin — four locks on the plate
Peripheral receptors too, inflamed tissue binds tight
Morphine hits mu hard, pure agonist profile right
But kidneys failing? Metabolite accumulates
Morphine-6-glucuronide piles up, respiratory fate
Histamine releasing, watch the pressure cascade
Full agonist potency, but caution must be weighed
[Chorus]
Full agonists, partial, antagonists — three tiers to know
Morphine, fentanyl, methadone running the opioid show
Naloxone flips the switch when respiratory depression grows
Mu delta kappa nociceptin — four receptors in a row
Constipation never tolerates, that side effect won't go
Know your drug, know your patient — that's how clinical judgment flows
[Verse 2]
Fentanyl patch, don't apply near heat, absorption spikes fast
Opioid-naïve patients — contraindicated, that's the contrast
Delayed onset, delayed offset, reservoir in the skin
Buccal sublingual nasal routes when breakthrough pain moves in
Meperidine's near obsolete — normeperidine seizes brains
Serotonin syndrome lurking when you stack serotonergic chains
Codeine needs CYP2D6 to activate the kick
Ultra-metabolizers flood, pediatric patients — skip
[Chorus]
Full agonists, partial, antagonists — three tiers to know
Morphine, fentanyl, methadone running the opioid show
Naloxone flips the switch when respiratory depression grows
Mu delta kappa nociceptin — four receptors in a row
Constipation never tolerates, that side effect won't go
Know your drug, know your patient — that's how clinical judgment flows
[Verse 3]
Methadone got a half-life nobody fully clocks
Variable, prolonged — QT interval unlocks
Torsades de pointes waiting if you don't watch the trace
Complex conversion math, specialist must take that case
Buprenorphine, partial agonist, ceiling on the respiratory dip
High affinity receptor grip means precipitated withdrawal trip
Pull full agonists before you switch — timing is the art
Perioperative planning starts before the patient's chart
[Bridge]
Tramadol and tapentadol lower seizure threshold gates
SNRI serotonergic activity complicates
Naltrexone, nalmefene — long antagonist duration
Methylnaltrexone stays peripheral, gut constipation
Respiratory depression: CO2 response gets blunted first
Sedation is the warning sign before the breathing's worst
Capnography catches it before pulse ox sounds the alarm
PCA, abuse-deterrent formulations — minimize the harm
[Chorus]
Full agonists, partial, antagonists — three tiers to know
Morphine, fentanyl, methadone running the opioid show
Naloxone flips the switch when respiratory depression grows
Mu delta kappa nociceptin — four receptors in a row
Constipation never tolerates, that side effect won't go
Know your drug, know your patient — that's how clinical judgment flows