Opiods Flashcards Preview

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Flashcards in Opiods Deck (21):
1

Strong opioid agonists

Morphine
Fentanyl
Sufentanil
Meperidine (PO)
Methadone
Oxycodone (Oxycontin)

2

Morphine

Strong opioid agonists
-Well tolerated when given in large doses to relieve pain
•Principal alkaloid of opium; diacetic acid ester of morphine is heroin
•Well absorbed orally, undergoes significant 1st pass metab → 3-glucuronide (inactive) or 6-glucuronide (more active, longer t1/2)
•USE: Severe pain, trauma, MI

3

Fentanyl
Sufentanil

Strong opioid agonists
•Most potent synthetic agonist
•Long-acting transdermal skin patch for severe chronic pain
•Parenterally pre-op and post-op as adjunct to general anesthesia → truncal rigidity

4

Meperidine

Strong opioid agonists
-PO
•Less pronounced smooth muscle → analgesia in obstetrics
•Anti-muscarinic properties: may cause pupils to dilate
•Short term tx of mod to severe pain; long term not recc, has neurotoxic metabolite → normeperidine → CNS excitation, convulsion, tremors

5

Methadone

Strong opioid agonists
•PO for opioid dependence or chronic pain
•Long t1/2, 1/day
•Methadone maintenance problem – reduce craving without causing significant euphoria or other reinforcing SE

6

Oxycodone (Oxycontin)

Strong opioid agonists
•Use with NSAID to treat mod to severe pain
•Sustained release = Oxycontin

7

Moderate opioid agonists

Codeine
Propoxyphene

8

Codeine

Moderate opioid agonists
•Methyl at 3-position → less first pass metab than morphine
•Converted to morphine via CYP2D6 → analgesic effect
•Combo with NSAID for mild to mod pain
•Anti-tussive in cough syrup (not for kids)

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Propoxyphene

Moderate opioid agonists
•Half analgesic potency of codeine
•OFF-MARKET → risk of potentially serious/fatal heart rhythm abnormality

10

AE's of opioid agonists

•Dysphoric reactions → behavioral restlessness (less likely if in pain)
•Respiratory depression → death in OD; reduced hypercapnic drive, no effect on hypoxic drive (medulla suppressed)
•Nausea/vomiting (ambulatory pts, chemo trigger zone stimulated)
•Constipation – little tolerance to this effect
•Urinary retention (incr bladder sphincter tone)
•Orthostatic hypotension (release of histamine from mast cells and vasodilation)
•Itching, rash (centrally mediated)
•Tolerance – decr in pharma effects, may involve compensatory incr in adenyl-cyclase, receptor endocytosis/degradation, receptor uncoupling; 2-3wks; marked tolerance to analgesic, sedating and resp depr effects; some tolerance to antidiuretic, emetic and hypotensive effects but not to miotic and constipating actions
•No tolerance to pure antags
•Cross tolerance, esp if mu-receptor activated – is incomplete, opioids can be rotated to maintain analgesia or add other agents
•Physical dependence – rhinorrhea, lacrimation, yawning, chills, piloerection, hyperventilation, hyperthermia, mydriasis, muscular aches, vomiting, diarrhea, anxiety, hostility (opposite of effects)
•Physical dep time of onset depends on t1/2 of drug
•Clonidine can treat some autonomic symptoms of withdrawal
•Psychological dependence – euphoria, indifference to stimuli and sedation promote compulsive use
•Drug interactions: sedative hypnotics incr resp depression, antipsychotic TCAs increase sedation and CV effects, MAOI potential for serotonin syndrome, partial agonist can precip withdrawal in pts tolerant to full ag
•OD: resp depression, miosis, coma
•Contraindications: pulm dysfunction (not pulm edema), closed head injuries, hepatic/renal dysfunction, adrenal/thyroid deficiency, pregnancy

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Other specific opioid agents

Tramadol
•Weak agonist at mu R, inhibits 5HT and NE reuptake → potentiate descending inhib pathways
•Moderate pain, chronic pain syndromes
•Abuse potential

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Dextromethorphan

Other specific opioid agents
•Analogue of codeine, anti-tussive
•Minimal analgesic + addictive properties
•Abuse of purified form reported
•Not for children under 6 (→death)

13

Diphenoxylate

Other specific opioid agents
•Combo with atropine for diarrhea
•Atropine reduced likelihood of abuse; low abuse potential

14

Loperamide

Other specific opioid agents
•Activates mu R in periphery
•Potential for abuse low, available OTC
•Diarrhea

15

Mixed opioid agonist-antagonists

Buprenorphine (PO, sublingual + naloxone)
Butorphanol (IV, intranasal)
Pentazocine

Less resp depr, safer in OD; less constipation, less abuse potential

16

Buprenorphine (PO, sublingual + naloxone)

Mixed opioid agonist-antagonists
•Partial agonist at mu R, antag at kappa/delta R
•Low dissociation from mu → longer duration of action
•Outpatient treatment of opioid abuse
•Relief of mod to severe pain; post-op
•AE: Less resp depression than morphine, but SE (nausea, sedation) not readily reversed by naloxone

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Butorphanol (IV, intranasal)

Mixed opioid agonist-antagonists
•Mu antag/partial agonist and kappa agonist
•Acute pain relief
•AE: Sedation, nausea, sweating

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Pentazocine

Mixed opioid agonist-antagonists
•Mu antag/partial agonist and kappa agonist
•Mod to severe pain
•PO (+naloxone) for mod to severe pain, IV for preanesthetic/supplement to surgical anesthesia
•AE: Anxiety, nightmares, psychotomimetic effects (sigma receptor stim)
•Nausea, sweating

19

Opioid antagonists

Naloxone
Naltrexone (PO, transdermal)

20

Naloxone

Opioid antagonists
•IV, block respiratory depression of opioid agonist
•Works within 30s, may need to repeat dose if long-acting opioid
•Oral prep: combo with opioid agonist to prevent IV abuse
•AE: Antags can precipitate transient and explosive withdrawal within 3 min (diagnose OD or reverse severe resp depression)

21

Naltrexone (PO, transdermal)

Opioid antagonists
•Treat opioid dependence and alcoholism, not for acute toxicity
•Longer duration than nalozone (48hr)
•AE: Hepatotoxicity, nausea, sedation, headache