Opioid Analgesics
| Drug Class | Schedule | Primary Use | Antidote |
|---|---|---|---|
| Opioid agonists | Mostly DEA Schedule II (tramadol: Schedule IV) | Moderate-severe acute and chronic pain | Naloxone (Narcan) |
Mahahalagang Punto
- Mechanism: Kumakabit sa mu, delta, at kappa opioid receptors sa CNS → binabago ang pain perception, itinataas ang pain threshold, at nagdudulot ng CNS depression
- Primary adverse effect: Respiratory depression - i-monitor ang respiratory rate; rate <12/min → i-withhold at i-notify ang provider; panatilihin ang naloxone sa bedside
- Ang Constipation ang pinaka-persistent na adverse effect - HINDI nagkakaroon ng tolerance; nangangailangan ng proactive bowel management
- Ang Morphine ang prototype opioid; walang ceiling effect → angkop para sa cancer pain at end-of-life care
- Sa acute coronary syndromes, secondary option ang morphine para sa persistent pain kapag hindi sapat ang optimal nitroglycerin therapy.
- Meperidine (Demerol): HINDI inirerekomenda para sa routine analgesia - ang toxic metabolite nito ay nagdudulot ng delirium at seizures, lalo na sa elderly at renal-impaired patients
- Iwasan ang opioid-first strategies para sa chronic noncancer pain kapag may epektibong alternatives, at iwasan ang routine opioid-first use sa patients younger than 18 years
- Karamihan sa full opioid agonists ay Schedule II controlled substances, habang Schedule IV ang tramadol; parehong nangangailangan ng controlled-substance safeguards
- Mas mabagal at mas variable ang IM opioid onset kaysa IV; sa low-perfusion states (halimbawa shock o chilled tissue) maaaring maantala ang absorption at tumaas ang overdose risk habang bumabalik ang circulation.
- Maaaring mabilis na maibalik ng naloxone reversal ang ventilation ngunit nire-reverse din nito ang opioid analgesia; muling suriin nang magkasabay ang pain at respiratory status pagkatapos ng rescue.
- Maikli ang naloxone duration (madalas mga 20-30 minuto), kaya maaaring bumalik ang sedation/respiratory depression kapag long-acting opioids ang sangkot.
Mechanism of Action
Kumakabit ang opioid agonists sa opioid receptors (pangunahing mu receptors) na nasa buong CNS at peripheral tissues. Ang receptor activation ay nagdudulot ng:
- Analgesia: Minomodulate ang painful signals mula peripheral tissues; tumataas ang pain threshold
- Euphoria/sedation: CNS depression sa pamamagitan ng limbic at cortical pathways
- Cough suppression: Sinusupil ang cough center sa medulla
- Respiratory depression: Binabawasan ang responsiveness ng brain stem respiratory centers sa CO2 - pangunahing life-threatening adverse effect
Key Opioid Agents
| Drug | Route | Typical Adult Dose | Notes |
|---|---|---|---|
| Morphine | IV, PO | IV PCA: 1-2 mg per bolus; PO: 15-30 mg q4h IR | Prototype opioid; no ceiling effect; ginagamit sa severe pain, cancer/end-of-life care, at selected pulmonary-edema contexts; common sa PCA |
| Morphine concentrate (Roxanol) | Sublingual, PO | Concentration often 20 mg/mL; dose individualized | Common sa end-of-life care para sa pain o air hunger kapag limitado ang swallowing; muling suriin ang comfort-alertness balance |
| Fentanyl (Sublimaze, Duragesic) | IV, transdermal | Acute: 25-50 mcg IV q30-60 min; Patch: 25-100 mcg/hr | Synthetic - safe alternative para sa morphine allergy; extremely potent; major contributor sa opioid overdose deaths |
| Hydromorphone (Dilaudid) | IV, PO | IV: 0.2-1 mg q2-3h; PO: 2-4 mg q4-6h | Semisynthetic; potent; available sa parehong forms para sa in/out-hospital use |
| Tramadol (Ultram) | PO (IR/ER) | IR: 50 mg; ER: 100/200/300 mg | Schedule IV atypical agent: partial mu agonist + NE/5-HT reuptake inhibition; kapaki-pakinabang sa selected pain contexts ngunit nagpapababa ng seizure threshold at may misuse risk |
| Oxycodone (OxyContin, Xtampza ER) | PO | IR: 5-15 mg q4-6h; ER: individualized | Mas kaunting pruritus kaysa morphine; madalas isinasama sa acetaminophen (i-monitor ang total APAP dose ⇐4 g/day) |
| Codeine | PO | 15-60 mg q4h; max 360 mg/day | Nangangailangan ng CYP2D6 conversion sa morphine; unpredictable ang response; HINDI inirerekomenda sa children |
| Methadone (Dolophine) | PO, IV | Individualized | Half-life hanggang 59 hours; ginagamit para sa opioid-use-disorder(opioid use disorder) at chronic pain; may benepisyo sa neuropathic pain |
| Meperidine (Demerol) | IM, SQ | 50-150 mg q3-4h; max 600 mg/day | HINDI para sa routine analgesia - toxic metabolite (normeperidine) ay nagdudulot ng CNS excitability, [delirium], seizures; limitahan sa shivering (rigors) management |
Adverse Effects
| System | Adverse Effect | Clinical Action |
|---|---|---|
| Respiratory | Respiratory depression (RR <12/min) | I-withhold ang opioid; i-stimulate ang patient; mag-administer ng naloxone |
| CNS | Sedation, confusion, dizziness, lightheadedness | Fall precautions; side rails up; assist ambulation |
| Cardiovascular | Hypotension (vasodilation) | Dahan-dahang position changes; i-monitor ang BP; iwasan sa hypovolemia |
| GI | constipation(paninigas ng dumi) (no tolerance develops), nausea, vomiting | Bowel regimen (stool softener + stimulant laxative); anti-emetics |
| Urinary | Urinary retention (higher risk in opioid-naive or spinal-route opioid use) | I-monitor ang urine output; suriin ang bladder distention; catheterize kung kailangan |
| Dermatologic | Pruritus (especially with spinal-route opioids) | Antihistamines; i-monitor ang dagdag na sedation kung may diphenhydramine |
| Neurologic (tramadol risk) | Lowered seizure threshold, especially with overdose/polypharmacy | Mag-ingat kung may seizure history; agad mag-escalate para sa tremor, confusion, o seizure activity |
Respiratory Depression
Ang respiratory depression ang pangunahing life-threatening risk ng opioid use. Pinakamataas ang risk sa:
- Elderly at debilitated patients
- Patients na may COPD, sleep apnea, o decreased respiratory reserve
- Kapag pinagsabay sa ibang CNS depressants (benzodiazepines, alcohol, sedative-hypnotics)
- Kapag first doses sa opioid-naive patients
Naloxone (Narcan) - Opioid Antidote
Mechanism: Competitive opioid receptor antagonist - mabilis na inaalis ang opioids mula sa receptors at nire-reverse ang CNS/respiratory depression.
Indications: Complete o partial reversal ng opioid-induced respiratory depression; suspected opioid overdose.
Administration: IV push (pinakamabilis), IM, o intranasal route; ulitin every 2-3 minutes hanggang sapat ang respiratory response. Maikli ang effect (madalas mga 20-30 minutes at karaniwang mas maikli kaysa maraming opioids), kaya maaaring mangyari ang re-sedation at kailangan ng repeat doses o infusion.
Naloxone Cautions
- Nagdudulot ng acute withdrawal sa opioid-dependent patients - signs: sweating, tachycardia, hypertension, vomiting, severe agitation, seizures
- Maaari ring magpakita ng diarrhea at tremors ang withdrawal pagkatapos ng abrupt reversal
- Neonates ng opioid-dependent mothers: HUWAG mag-administer ng naloxone - nagdudulot ng neonatal withdrawal na may convulsions
- Ang abrupt reversal sa postoperative opioid-dependent patients ay maaaring magdulot ng severe hypertension, ventricular dysrhythmias, pulmonary edema
Nursing Monitoring Priorities
Bago Mag-administer:
- Suriin ang pain gamit ang validated scale (0-10, FACES, behavioral)
- Mas mainam ang oral/IV/subcutaneous/rectal/transdermal routes kung naaangkop; karaniwang iniiwasan ang intramuscular opioid administration kapag may alternatives
- Kung kailangan ang IM opioid dosing, i-monitor nang mahigpit sa low-perfusion states dahil maaaring magdulot ng delayed absorption at later rebound sedation/respiratory depression.
- Suriin ang baseline respiratory rate, LOC, blood pressure
- Suriin ang kasalukuyang medications para sa CNS depressants (benzodiazepines, alcohol history)
- I-verify ang opioid history at tolerance status
- Kumpirmahin ang controlled substance documentation (count, witness)
- I-screen ang high-risk caution contexts bago morphine use: head injury/increased ICP, GI obstruction (lalo na paralytic ileus), biliary/pancreatic disease, severe hepatic/renal impairment, convulsive disorders, at circulatory shock/hypovolemia.
Habang Therapy:
- Respiratory rate - q1-4h depende sa route; RR <12/min → i-withhold at i-notify ang provider
- Level of consciousness - sedation scale assessment
- Pain reassessment - 30-60 min pagkatapos ng IV dose; 60 min pagkatapos ng PO dose
- Sa final-hours comfort care, muling suriin ang dyspnea relief at kakayahang makipag-ugnayan, at i-titrate ayon sa patient-defined comfort-alertness goal.
- Pagkatapos ng naloxone reversal, i-monitor ang recurrent respiratory depression, hypertension/tachyarrhythmia, at pagbabalik ng severe pain.
- Bowel function - araw-araw; simulan ang prophylactic bowel regimen kasabay ng initial opioid order
- Urinary output - lalo na sa epidural o intrathecal opioids
Safety:
- Fall precautions - bed sa lowest position, call light within reach, non-skid footwear
- Nakataas ang side rails kapag sedated
- Agarang available ang naloxone sa bedside habang may IV opioid use
Patient Education:
- Huwag magmaneho o mag-operate ng heavy machinery
- Iwasan ang alcohol at CNS depressants
- Huwag i-tamper ang opioid formulations (halimbawa crushing, chewing, snorting, o injecting) dahil malaki ang pagtaas ng overdose at death risk.
- Dahan-dahang magpalit ng posisyon (orthostatic hypotension)
- I-report ang: RR <12/min, extreme drowsiness, inability to be woken
- Inumin kasama ng pagkain upang mabawasan ang nausea
- Inaasahan ang constipation - inumin ang prescribed laxative/stool softener
Mga Kaugnay na Konsepto
- analgesics - Ang opioids ay Tier 3 (WHO analgesic ladder) para sa moderate-to-severe pain
- opioid antagonists - Naloxone, naltrexone, at mixed agonist-antagonist pathways.
- NSAIDs - Non-opioid analgesics na ginagamit sa multimodal analgesia para mabawasan ang opioid requirements
- pain management - PCA delivery, opioid-sparing strategies, monitoring protocols
- labor analgesics - Opioid use sa labor; lahat tumatawid sa placenta; naloxone antidote considerations
- substance use disorders - opioid use disorder, addiction risk, drug diversion
- sedative-hypnotics - Additive CNS/respiratory depression kapag pinagsama sa opioids
Sariling Pagsusuri
- Isang postoperative patient na tumatanggap ng IV morphine via PCA ay may respiratory rate na 10/min at mahirap gisingin. Ano ang agarang nursing priority?
- Nag-administer ang nurse ng naloxone sa patient na may suspected opioid overdose. Bumuti ang respirations ng patient, ngunit 45 minuto ang lumipas ay may renewed sedation at RR na 11. Bakit ito nangyayari, at ano ang dapat gawin ng nurse?
- Isang elderly patient na may COPD at moderate-to-severe cancer pain ang niresetahan ng around-the-clock morphine. Anong special monitoring parameters ang dapat sa patient na ito?