Opioid Agonists

Name of the Opioid Agonists

1. Codeine
2. Fentanyl
3. Hydromorphone
4. Oxycodone
5. Morphine

1.CODEINE

Mechanism of Action​

Narcotic agonist analgesic with antitussive activity, mu receptor agonist​

Absorption

• Onset: 30-60 min (PO); 10-30 min (IM)
• Duration: 4-6 hr

Metabolism and Half Life

Prodrug metabolized to morphine by CYP2D6; demethylated/conjugated in liver (undergoes O-demethylation, N-demethylation, and partial conjugation with glucuronic acid)

Half-life: 3-4 hr

Excretion: Urine, feces

Indications:

• Relief of mild to moderate pain in adults and children
• Suppression of coughing induced by chemical or mechanical irritation of the respiratory system

Contraindications

• Hypersensitivity to codeine
• Significant respiratory depression
• Children younger than 12 years
• Postoperative pain management in children (<18 years) who have undergone tonsillectomy and/or adenoidectomy
• Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment
• Concurrent use of monoamine oxidase inhibitors (MAOIs) or use of MAOIs within last 14 days
• Known or suspected gastrointestinal obstruction, including paralytic ileus

Drug interactions:

• Do not drink alcohol while you are taking Codeine
• other sedative drugs which may enhance the drowsiness caused by Codeine Phosphate Injection USP
• other opioid analgesics (drugs used to treat pain)
• general anaesthetics (drugs used during surgery)
• benzodiazepines (drugs used to help you sleep or that help reduce anxiety)
• antidepressants (for depression and mood disorders). Do not take Codeine Phosphate Injection USP with MAO inhibitors (MAOi) or if you have taken MAOi’s in the last 14 days.

Side – effects

• Hypotension
• Tachycardia or bradycardia
• Confusion, Dizziness, Malaise
• False feeling of well-being
• Headache
• Light-headedness
• Paradoxical CNS stimulation
• Restlessness
• Rash, urticaria
• Anorexia​
• Nausea, vomiting​
• Xerostomia​
• Ureteral spasm, urination decreased​
• Burning at injection site​
• Blurred vision​
• Dyspnea​

 Nursing considerations

CLINICAL ALERT! Name confusion has occurred between codeine and Cardene (nicardipine) and Lodine (etodolac); use caution.

Assessment

• History: Hypersensitivity to codeine, physical dependence on an opioid analgesic, pregnancy, labor, lactation, bronchial asthma, COPD, increased intracranial pressure, acute MI, ventricular failure, coronary insufficiency, hypertension, biliary tract surgery, renal or hepatic impairment
• Physical: Orientation, reflexes, bilateral grip strength, affect; pupil size, vision; pulse, auscultation, BP; R, adventitious sounds; bowel sounds, normal output; LFTs, renal function tests

Interventions

• Give to nursing women 4–6 hr before scheduled feeding to minimize drug in milk.
• WARNING: During parenteral administration, ensure that opioid antagonist and facilities for assisted or controlled respirations are readily available.
• Use caution when injecting subcutaneously into chilled body areas or in patients with hypotension or in shock; impaired perfusion may delay absorption; with repeated doses, an excessive amount may be absorbed when circulation is restored.
• WARNING: Do not use IV in children.
• Instruct postoperative patients in pulmonary toilet; drug suppresses cough reflex.
• Monitor bowel function, arrange for laxatives (especially senna compounds—approximate dose of 187 mg senna concentrate per 120 mg codeine equivalent), bowel training program if severe constipation occurs.

Patient and Family Teaching

• Take drug exactly as prescribed.
• Do not take any leftover medication for other disorders, and do not let anyone else take it.
• You may experience these side effects: Dizziness, sedation, drowsiness, impaired visual acuity (avoid driving and performing other tasks that require alertness); nausea, loss of appetite (lie quietly; eat frequent small meals); constipation (use a laxative).
• Report severe nausea, vomiting, palpitations, shortness of breath or difficulty breathing.

Mechanism of Action:

Binds to opioid receptors in CNS, reducing stimuli from sensory nerve endings; inhibits ascending pain pathways.

Metabolism and Half-life:

Well absorbed after IM or topical administration. Transmucosal form absorbed through buccal mucosa and GI tract. Protein binding: 80%–85%. Metabolized in liver. Primarily excreted by biliary system. Half-life: 2–4 hrs IV; 17 hrs transdermal; 6.6 hrs transmucosal.

Drug Interactions:

• Strong CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole, ritonavir), cimetidine may increase concentration/effect; risk for respiratory depression.
• Alcohol, CNS depressants (e.g., Lorazepam, haloperidol, zolpidem) may increase CNS depression.
• May increase serotonergic effect of MAOIs (e.g., phenelzine, selegiline).

Indications:

• Pain relief
• •Preop medication
• Adjunct to general or regional anaesthesia.
• Treatment of breakthrough pain in cancer pts 18 yrs of age and older.
• Treatment of breakthrough pain in chronic cancer or AIDS-related pain.
• Management of chronic pain (transdermal).
• Breakthrough pain in pts on chronic opioids.
• Short-term management of acute postoperative pain in adults.

Cautions & Contraindications:

• Hypersensitivity
• Transdermal device (additional): Significant respiratory depression, acute/severe bronchial asthma, paralytic ileus, GI obstruction.
• Transdermal patch (additional): Significant respiratory depression, acute/severe bronchial asthma, paralytic ileus, short-term therapy for acute or postoperative pain, pts who are not opioid tolerant.
• Transmucosal buccal, buccal films, lozenges, sublingual tablets/spray, nasal spray (additional): Management of acute or postoperative pain, pts who are not opioid tolerant. GI obstruction, significant respiratory depression (Actiq, Fentora only), acute or severe bronchial asthma.
• Cautions: Bradycardia; renal, hepatic, respiratory disease; head injuries; altered LOC; biliary tract disease; acute pancreatitis; cor pulmonale; significant COPD; increased ICP; use of MAOIs within 14 days; elderly; morbid obesity

SIDE EFFECTS

• Frequent: IV: Postop drowsiness, nausea, vomiting.
• Transdermal (10%– 3%): Headache, pruritus, nausea, vomiting, diaphoresis, dyspnoea, confusion, dizziness, drowsiness, diarrhoea, constipation, decreased appetite.
• Occasional: IV: Postop confusion, blurred vision, chills, orthostatic hypotension, constipation, difficulty urinating. Transdermal (3%–1%): Chest pain, arrhythmias, erythema, pruritus, syncope, agitation, skin irritations.
• Overdose or too-rapid IV administration may produce severe respiratory depression, skeletal/thoracic muscle rigidity (may lead to apnea, laryngospasm, bronchospasm, cold/clammy skin, cyanosis, coma). Tolerance to analgesic effect may occur with repeated use.
• Abrupt stoppage of prolonged high dose, continuous infusions may induce opiate withdrawal

 NURSING CONSIDERATIONS

 Baseline assessment

• Resuscitative equipment, opiate antagonist (naloxone 0.5 mcg/kg) should be available for initial use.
• Establish baseline B/P, respirations.
• Assess type, location, intensity, duration of pain.
• Determine daily morphine equivalency in cancer pts who are being transitioned to chronic therapy.

 INTERVENTION/EVALUATION

• Assist with ambulation.
• Encourage postop pt to turn, cough, deep breathe q2h.
• Monitor respiratory rate, B/P, heart rate, oxygen saturation.
• Assess for relief of pain.
• In pts with prolonged high dose, continuous infusions (critical care, ventilated pts), consider weaning drip gradually or transition to a fentanyl patch to decrease symptoms of opiate withdrawal

Patient/family teaching:

• Avoid alcohol
• Do not take other medications without consulting physician.
• Avoid tasks that require alertness, motor skills until response to drug is established.
• Teach pt proper transdermal, buccal, lozenge administration.
• Transdermal: Avoid saunas (increases drug release time).
• Use as directed to avoid overdosage, potential for physical dependence with prolonged use.
• Report constipation, absence of pain relief.
• Taper slowly after long-term use.

Mechanism of Action:

 Binds to opioid receptors in CNS, reducing intensity of pain stimuli from sensory nerve endings. Therapeutic Effect: Alters perception, emotional response to pain; suppresses cough reflex.

Indications:

• Relief of moderate to severe pain.
• Extended-release tablet: Around the clock, continuous analgesia for extended period.

Cautions & Contraindications:

• Hypersensitivity
• Acute or severe bronchial asthma
• severe respiratory depression.
• GI obstruction including paralytic ileus (known or suspected). 
• Pre-existing GI surgery/ diseases causing GI narrowing.
• Cautions: Severe hepatic, renal, respiratory disease, hypothyroidism, seizures, acute alcoholism, head injury, increased intracranial pressure, prostatic hypertrophy, Addison’s disease, urethral stricture, cardiovascular disease, pts with CNS depression or coma, pts with depleted blood volume, obstructive bowel disorder

Metabolism and Half- life:

• Well absorbed from GI tract after IM administration. Widely distributed. Metabolized in liver.
• Excreted in urine. Half- life: 2.6–4 hrs.

SIDE EFFECTS

• Drowsiness
• Dizziness
• Hypotension (including orthostatic hypotension)
• Decreased appetite
• Confusion
• Diaphoresis
• Facial flushing
• Overdose results in respiratory depression, skeletal muscle flaccidity, cold/clammy skin, cyanosis, extreme drowsiness progressing to seizures, stupor, coma. Tolerance to analgesic effect, physical dependence may occur with repeated use.

NURSING CONSIDERATIONS

Baseline assessment

• Obtain vital signs. If respirations are 12/ min or less (20/min or less in children), withhold medication, contact physician. Analgesic: Assess onset, type, location, duration of pain.
• Effect of medication is reduced if full pain recurs before next dose.
• Antitussive: Assess type, severity, frequency of cough.

Intervention/evaluation

• Monitor vital signs; assess for pain relief, cough. To prevent pain cycles, instruct pt to request pain medication as soon as discomfort begins.
• Monitor daily pattern of bowel activity, stool consistency (esp. in long-term use).
• Initiate deep breathing and coughing exercises, particularly in pts with pulmonary impairment.
• Assess for clinical improvement, record onset of relief of pain, cough.

Patient/family teaching:

• Avoid alcohol; Avoid tasks that require alertness/motor skills until response to drug is established.
• Tolerance or dependence may occur with prolonged use at high dosages.
• Change positions slowly to avoid orthostatic hypotension.
• Do not chew, crush, dissolve, or divide extended- release tablets.

Mechanism of Action:

Binds with opioid receptors within CNS, causing inhibition of ascending pain pathway. Therapeutic Effect: Alters perception of and emotional response to pain.

Indications:

• Immediate-Release: Relief of acute or chronic, moderate to severe pain (usually in combination with nonopioid analgesics).
• Extended-Release: Around-the-clock management of moderate to severe pain when continuous analgesic is needed.

Cautions& Contraindications:

• Hypersensitivity
• Acute or severe bronchial asthma
• Hypercarbia
• Paralytic ileus (known or suspected)
• GI obstruction, significant respiratory depression.
• Extreme Caution: CNS depression, anoxia, hypercapnia, respiratory depression, seizures, acute alcoholism, shock, untreated myxoedema, respiratory dysfunction.
• Cautions: Elevated ICP, hepatic/renal impairment, coma, debilitated pts, head injury, biliary tract disease, acute abdominal conditions, hypothyroidism, urethral stricture, COPD, history of substance abuse, elderly patients.

Metabolism and Half –Life :

Moderately absorbed from GI tract. Protein binding: 38%–45%. Widely distributed. Metabolized in liver. Excreted in urine. Unknown if removed by haemodialysis. Half-life: 2–3 hrs (5 hrs controlled-release).

Drug Interactions:

• Alcohol, other CNS depressants may increase CNS effects, respiratory depression, hypotension.
• MAOIs may produce serotonin syndrome, a severe, sometimes fatal reaction.
• Grapefruit products may increase potential for respiratory depression.

Side – Effects: ​

• Effects are dependent on dosage amount. Ambulatory pts, pts not in severe pain may experience dizziness, nausea, vomiting, hypotension more frequently than those in supine position or having severe pain. ​
• Drowsiness​
• Dizziness​
• Hypotension (including orthostatic hypotension)​
• Anorexia​
• Confusion, ​
• Diaphoresis, facial flushing​
• Urinary retention, constipation, dry mouth​
• Nausea, vomiting, headache.​
• Overdose results in respiratory depression, skeletal muscle flaccidity, cold/ clammy skin, cyanosis, extreme drowsiness progressing to seizures, stupor, coma. ​

NURSING CONSIDERATIONS

Baseline assessment

• Assess onset, type, location, duration of pain.
• Effect of medication is reduced if full pain recurs before next dose.
• Obtain vital signs before giving medication. If respirations are 12/min or less (20/min or less in children), withhold medication, contact physician.

Intervention/evaluation

• Palpate bladder for urinary retention.
• Monitor daily pattern of bowel activity, stool consistency.
• Initiate deep breathing, coughing exercises, esp. in pts with pulmonary impairment.
• Monitor pain relief, respiratory rate, mental status, B/P, LOC.

Patient/family teaching

• May cause dry mouth, drowsiness.
• Avoid tasks that require alertness, motor skills until response to drug is established.
• Avoid alcohol.
• May be habit forming.
• Do not chew, crush, dissolve, or divide controlled-release tablets.
• Report severe constipation, absence of pain relief.

Mechanism of Action:

Binds with opioid receptors within CNS, inhibiting ascending pain pathways. Therapeutic Effect: Alters pain perception, emotional response to pain.

Indications:

• Relief of moderate to severe, acute, or chronic pain
• Analgesia during labour
• Pain due to MI
• Dyspnoea from pulmonary Edema not resulting from chemical respiratory irritant.
• Extended release: use only when repeated doses for extended periods of time are required around the clock.

Contraindications:

• Hypersensitivity  
• Acute or severe asthma
• GI obstruction
• Known or suspected paralytic ileus
• Concurrent use of MAOIs or use of MAOIs within 14 days
• Severe respiratory depression.
• Extreme Caution: COPD, cor pulmonale, hypoxia, hypercapnia, preexisting respiratory depression, head injury, increased ICP, severe hypotension.
• Cautions: Biliary tract disease, pancreatitis, Addison’s disease, cardiovascular disease, morbid obesity, adrenal insufficiency, elderly, hypothyroidism, urethral stricture, prostatic hyperplasia, debilitated pts, pts with CNS depression, toxic psychosis, seizure disorders, alcoholism

Metabolism and Half- life:

Variably absorbed from GI tract. Readily absorbed after IM, SC administration. Protein binding: 20%–35%. Widely distributed. Metabolized in liver. Primarily excreted in urine. Removed by hemodialysis.

Half-life: 2–4 hrs (increased in hepatic disease).

Drug Interactions:

• Alcohol, other CNS depressants may increase CNS effects, respiratory depression, hypotension.
• MAOIs may produce serotonin syndrome. (Reduce dosage to one-fourth of usual morphine dose.)
• HERBAL: Herbals with sedative properties may increase CNS depression

Side effects:

• Ambulatory pts, pts not in severe pain may experience nausea, vomiting more frequently than pts in supine position or who have severe pain.
• Sedation
• Decreased B/P (including orthostatic hypotension)
• Diaphoresis
• Facial flushing
• Constipation
• Dizziness
• Drowsiness
• Nausea, vomiting.
• Overdose results in respiratory depression, skeletal muscle flaccidity, cold/ clammy skin, cyanosis, extreme drowsiness progressing to seizures, stupor, coma. Tolerance to analgesic effect, physical dependence may occur with repeated use. Prolonged duration of action, cumulative effect may occur in those with hepatic/renal impairment.

NURSING CONSIDERATIONS

Baseline assessment

• Patient should be in recumbent position before drug is given by parenteral route.
• Assess onset, type, location, duration of pain.
• Obtain vital signs before giving medication. If respirations are 12/min or less (20/min or less in children), withhold medication, contact physician.
• Effect of medication is reduced if full pain recurs before next dose.

Intervention/evaluation

• Monitor vital signs 5–10 min after IV administration, 15–30 min after SC, IM.
• Be alert for decreased respirations, B/P.
• Check for adequate voiding.
• Monitor daily pattern of bowel activity, stool consistency; avoid constipation.
• Initiate deep breathing, coughing exercises, particularly in those with pulmonary impairment.
• Assess for clinical improvement, record onset of pain relief. Consult physician if pain relief is not adequate. 

Patient/family teaching

• Discomfort may occur with injection.
• Change positions slowly to avoid orthostatic hypotension.
• Avoid tasks that require alertness, motor skills until response to drug is established.
• Avoid alcohol, CNS depressants.
• Tolerance, dependence may occur with prolonged use of high doses.
• Report ineffective pain control, constipation, urinary retention

REFERENCES

1. Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
2. McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
3. April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
4. Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
5. Nursebro.com, Search – Nursebro

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