Strong opioid agonist

Mechanism: binds all opioid receptors (GPCRs) that 1. closes Ca channels presynaptic, decreasing NT release and 2. opens K channels postsynaptic, hyperpolarizing and inhibiting postsynaptic neuron

Use: Analgesia, acute pulmonary edema, cough, diarrhea, anesthesia

Pharmacokinetics: High first pass metabolism CYP450 in liver, and kidneys; excreted as morphine-3-glucornide; Morphin 6-glucuronide = more pontent analgesic metabolite; Morphine 3-glucuronide = may cause hyperalgesia

Side effects: itching, vomiting, can cross placenta in pregnancy and cause resp dep. and dependance w/ chronic use

DO NOT BECOME TOLERANT TO MIOSIS OR GI EFFECTS  (CONSTIPATION) OF OPIOIDS!

Strong opioid agonist

More potent than morphine; duration of action slightly shorter than morphine

Use: Moderate-severe pain, very strong analgesic

Useful in pts with renal dysfunction as metabolites DO NOT accumulate

Strong opioid agonist

Drug of abuse in US, Schedule I (no medical use)

easily passes BBB and metabolized to morphine

10X more potent than morphine

Strong opioid agonist

Longer duration than morphine

Mechanism: binds Mu receptor, also block NMDA receptors and inhibit NE/5HT reuptake

Use: hard to treat types of pain (neuropathic pain, cancer) addiction, chronic pain, maintaenance therapy for heroin addicts

No real addiction potential, tolerance or euphoria

Strong opioid agonists (odd man out)

Use: analgesia; recommended only for very brief course in healthy pts w/o opiate problems; second line agent for acute pain; not suitable for long term use

Effect: NO PUPILLARY CONSTRICTION (miosis) (actually dilates pupils from muscarinic block (mydriasis), Does not prolong labor; can cause euphoria

Mechanism: Mu agonist, also inhibits NE and 5HT reuptake (addiction)

Dx interactions: MAOIs! (phenylzine, selegiline, linezolid (antibiotic) = serotonin syndrom; TCAs and SSRIs because of mechanism

Side effects: seizures, tachy, pupil DILATION, no cough suppression; serotonin syndrome with MAOIs

Difference from other opioids: 

Strong opioid agonist

High abuse potential (highley potent, 100X morphine); duration of action shorter than morphine/meperidine

Use: short surgical procedures (induction/GA maintenance); supplement regional/spinal analgesia; transdermal for chronic pain

*preferred to morphine for hemodynamic responses and maintain cardiac stability*

Transdermal patches or lollipops available

Side effects: truncal rigidity (IV), CYP3A4 metabolized

Metabolized by CYP3A4 extensively (dx interactions)

Strong opioid agonist

Faster action/shorter duration than fentanyl

Use: Anesthesia

IV or epidurally

Alfentanil undergoes biotransformation via CYP3A4

Other drugs: Sufentanil (Sufenta); Remifentanil (Ultiva)

Moderate to strong opiate agonist

Use: moderate to severe pain, often abused

Schedule II alone or III with acetaminophen (Vicodin)

Side effects: CYP2D6 metabolizm (SSRI and quinidine inhibit CYP2D6)

Moderate to strong opiate agonist

Use: moderate to severe pain, tourette's and restless leg syndrome; CA pain, post-op, post-extraction, post-partum pain; often abused (schedule II)

Metabolized by CYP2D6 for active metabolite so no SSRI and MAOI

Other drugs: oxymorphone - DOESN'T NEED CYP2D6 CONVERSION, so can be used in SSRI and MAOI taking pts

Moderate opiate agonist; antitussive

Use: Mild-moderate Pain, cough (weak analgesic but good antitussive); "low abuse potential"

DOESN'T BIND MU, SO WON'T COMPETE WITH STRONG AGONISTS

Partial CYP26 metabolism, converted to morphine (analgesic effect)

other drugs: Propoxyphene (Darvon; off market)

Moderate opiate agonist

Use: Mild-moderate pain (not a scheduled drug in most states, IV in 10 states)

Mechanism: Weak Mu agonist; Inhibits NE/5-HT reuptake, contributes to analgesic effect

Drug interactions: combo with antidepressants = seizures; combo with MAOIs, TCAs, SSRIs = serotonin syndrome; Naloxone WILL NOT completely inhibit analgesia

Side effects: dizziness, sedation, constipation, nausea

Mixed Opioid agonist-antagonist

Use: heroin addiction, decreases cravings

Mechanism: partial agonist on Mu, maybe Kappa

"ceiling effect", doesn't cause much euphoria so low abuse potentian

Combined with naloxone - if you inject it it won't work but sublingualy it will

Mixed opioid agonist-antagonist

Mechanism: Kappa agonist, partial Mu agonist

Use: Moderate pain (not for addicts or severe pain)

Less resp dep, and GI effects (Mu)

Dx interactions: competes with opioids

*Can precipitate withdrawal in opioid addicts (partial Mu)*

Side effects: dysphoria (Kappa), CNS stim, hallucinations

Pure Opioid antagonist (all receptors)

ESTABLISH AIRWAY then give Naloxone on opioid OD

Use: DOC opioid OD, can reverse resp depressant effects of OD, 

Pharmacokinetics: short acting (2 hrs), must monitor lest opioid lasts longer than the naloxone (may need repeated dose)

Must be injected

Opioid antagonist

Effective orally, long acting (24 hours)

Use: Tx of opioid addicts (prevents use of opioids as they won't work anymore), especiallly health care professionals; alcoholics (decrease craving)

Pt must be detoxed BEFORE naltrexone (ReVia) therapy can be initiated. 

Side effects: will precipitate withdrawal, liver toxicity

Other drugs: Nalmefene (Revex) - not as much liver toxicity, longer duration than naloxone (2-6 hours), used for chronic tx of EtOHism

Combo drugs

Other drugs: Oxycodone/aspirin (Percodan)

Antitussive

Use:cough suppressions w/o analgesia

Mechanism: Blocks NMDA receptors (abuse potential); Decrease 5-HT reuptake (serotonin syndrome with MAOIs)

Effect: less constipation than codein

Drug of abuse IN TEENAGERS; in cough syrup, tablet, concentration on internet

HAS CAUSED DEATH IN TEENS

Pure DMT ingestion OD (powder) can cause death, brain damage, seizures, loss of consciousness and irregular heart beat

Antidiarrheals

Other drugs: Loperamide (Imodium)