OPIOIDS AND ANALGESIA

Alberto Rivera Sanchez MD FAAPMR, ABPM, ABDAPain Management Sub SpecialistAmerican Board of Pain Medicine

DISCLOSURES: I HAVE RECEIVED EDUCATIONAL GRANTS FROM SEVERAL IMPLANT COMPANIES BUT NONE HAVE FUNDED OR INFLUENCED THE CONTENT OF THIS EDUCATIONAL MATERIAL

PHYSIOLOGIC & PHARMACOLOGIC EFFECTS

Nausea and VomitingSedation, sense of tranquility

ConstipationAnxiolysis, lethargyCough suppression

MiosisConstipation, pruritus, respiratory depression, delayed gastric emptying, sexual dysfunction,

muscle rigidity and myoclonus

MECHANISM OF ACTIONPresynaptic inhibition of of substance P releaseIncrease K+ conductance (hyperpolarization)

Inactivation of calcium channels

OPIOID RECEPTORS

Delta Receptors- its agonists produce analgesia on inflammatory mediated and malignant bone painAmoxapine, Ketamine, Norbuprenorphine

Kappa receptors- agonists are being developed to target inflammatory, visceral and chronic neuropathic pain Terpenoids in Cannabis Nalbuphine Pentazocine

MU RECEPTORS

μ1,μ2,μ3 subtypesPresent in the Brain, Spinal Cord, Peripheral sensory neurons and GI tract

OPIOID AGONISTSMorphine

HydromorphoneCodeineFentanylHeroin

MORPHINE

Agonist for all 3 MOR, KOR and DORCan be administered orally (IR & ER)IV, IM, Epidural, IntrathecalApproved by FDA for use in IT PumpsDuration of action in orally administered is longer than IV

HYDROMORPHONE1mg Hydromorphone = 5mg of MorphineIV, Rectal, SQ, Oral, Epidural, ITIV ½ life is 2.3 hrsHigh abuse potentialExcellent in cancer pain, fractures, burn unit, renal colicOral onset is 15 minutes

FENTANYLIV, IT, Oral, Transdermal (most popular for administration)Patch onset of action is 17 hours Oral onset of action is 7 minutes60-134mg Morphine equivalent to 25mcg Fentanyl patch10 times more potent than hydromorphoneAction is mostly mu1 receptor

TRAMADOL

Synthetic mu receptor agonistSerotonin-NE reuptake inhibitor1mg Morphine po = 10mg TramadolCardiac effects are rare: low BP, HBP, Inc. HR

OXYCODONE15mg Morphine po = 10mg Oxycodone poAbsorption is increased by fatty meals and ibuprophenGabapentin potentiates its analgesic effectsHas a IR and CR presentationIR ½ life is 3.2 hrs, onset 10-30 minCR onset of action 46 min, duration 10-12 hrs (Clin Pharm 1996)

ULTRA RAPID METABOLIZER

1-2% populationIncreased enzyme activity.

Increased formation of morphine following codeine administration, leading to higher risk of toxicity.Use Morphine or non opioids

NON-NARCOTICS FOR PAINAnti-depressants

Gabapentin/PregabalinBDZs

Muscle relaxantsNSAID’s

CHALLENGER IN THE HORIZONCannabis derived products with the correct

THC/CBD/terpenoid concentration