Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Morphine

USE IF: Severe pain, cancer pain, ICU analgesia, selected pulmonary edema cases

AVOID IF: Severe respiratory depression, paralytic ileus, severe renal failure (relative)

Morphine

Strong opioid (mu-opioid receptor agonist)

OpioidWHO Step IIIICU analgesiaPalliativeHigh-risk

Indication

Severe pain, cancer pain, ICU analgesia, selected pulmonary edema use

At a glance

INDICATION -> Severe pain (WHO Step III opioid)

ADULT DOSE -> 1–2 mg slow IV (opioid-naive); 0.1 mg/kg weight-based; titrate q5–10 min

MAX DOSE -> No ceiling (titrate); max 10 mg IV bolus opioid-naive

CONTRA -> Respiratory depression, paralytic ileus, severe renal failure

ANTIDOTE -> Naloxone (repeat dosing; infusion may be needed)

Quick facts

Onset

5 min (IV); 30 min (PO)

Duration

Peak 8–20 min (IV), 30–90 min (PO); duration 4–6 h (IV), 3–4 h (PO IR).

Routes

PO, IV, IM, SC, PR, intrathecal

Pregnancy

Use if needed; avoid chronic use

Renal

Avoid severe impairment

Hepatic

Reduce dose

Do not miss

Time to action: 5 min IV; 30 min PO

Max dose

  • No ceiling in monitored settings only; titrate with close RR and sedation monitoring.
  • Opioid-naive IV bolus max 10 mg.

Critical risks

  • Respiratory depression.
  • Apnea.
  • Hypotension.

Antidote

  • Naloxone with repeat dosing.
  • Infusion may be required due to re-narcotization.

High-risk scenarios

  • Renal failure (M6G accumulation).
  • Delayed respiratory depression risk (especially renal impairment and repeated dosing).
  • Rapid repeat IV dosing leads to dose stacking -> delayed respiratory depression.
  • Repeated IV boluses given too frequently -> cumulative toxicity and delayed respiratory depression.
  • Hold opioid if RR <8–10/min or patient is difficult to arouse (sedation toxicity).
  • Naloxone duration is shorter than morphine -> repeat dosing or infusion often required.
  • Monitor for re-sedation after reversal.
  • Elderly.
  • CNS depressants.

Key interactions

  • Benzodiazepines.
  • MAOI.
  • Alcohol.

Indications

Primary

  • Severe acute pain
  • Cancer pain
  • Trauma
  • Post-op pain

Secondary

  • Renal colic
  • MI pain
  • Sickle cell crisis
  • Palliative dyspnea

Other

  • Pulmonary edema (off-label)
  • Terminal cough

Dosing

Standard: IV 2—5 mg q3—4h or 0.1 mg/kg

Max daily dose

  • No fixed ceiling in opioid-tolerant settings; titrate to effect and safety.

Adult - PO

  • IR: 15–30 mg q4h.
  • MR: 15 mg q12h after titration.

Adult - IV

  • Opioid-naive: 1–2 mg IV slow bolus (opioid-naive).
  • Opioid-naive: start low, titrate slowly.
  • Opioid-tolerant: 2–5 mg IV titrated.
  • Opioid-tolerant: higher doses may be required but need specialist oversight.
  • Repeat IV doses every 5–10 minutes based on response to avoid dose stacking.
  • Do not repeat IV boluses more frequently than every 5 minutes.
  • Infusion: 0.8–10 mg/h.

Pediatric

  • Strict weight-based dosing only: 0.1–0.2 mg/kg IV q2–4h.

Renal adjustment

  • Use reduced doses; high risk of metabolite accumulation (M6G).
  • Avoid or use very low doses in eGFR <30 due to high risk of delayed respiratory depression (M6G accumulation).

Hepatic adjustment

  • Reduce 25–50%.
  • Extend interval.

Warnings

Clinical warnings

  • Respiratory depression (black box).
  • Addiction and misuse.
  • Hypotension with rapid IV push.
  • CNS depression with benzodiazepines.
  • Opioid-induced hyperalgesia with chronic use.
  • Neonatal withdrawal syndrome.
  • Constipation (universal).
  • Histamine release with IV dosing.

Adverse effects

  • Common: nausea, vomiting, sedation, constipation, pruritus.
  • Serious: respiratory depression, hypotension, opioid toxicity.

Contraindications / caution

Do not use

  • Respiratory depression.
  • Paralytic ileus (absolute contraindication).
  • Acute severe asthma (unmonitored).
  • MAOI use.

Use caution / avoid high doses

  • Renal failure.
  • Elderly.
  • Head injury.
  • Raised intracranial pressure / head injury (risk of CO2 retention and worsening ICP).
  • Hypotension.
  • Liver disease.

Drug interactions

  • Benzodiazepines -> respiratory depression/death.
  • MAOI -> caution (risk of CNS/respiratory depression).
  • Alcohol -> additive CNS depression.
  • Anticholinergics -> constipation/retention.

Special populations

Pediatrics

Weight-based specialist dosing and close respiratory monitoring.

Pregnancy

Short-term use acceptable; avoid chronic use (NOWS).

Breastfeeding

Preferred strong opioid in some settings; monitor infant.

Elderly

Start at 50% dose.

Liver disease

Reduce dose and extend interval.

Renal impairment

Avoid or use very low doses in eGFR <30 due to high risk of delayed respiratory depression (M6G accumulation).

Administration

  • IV preferred in acute care.
  • IV must be given slowly over >=4–5 minutes.
  • Avoid rapid IV push.
  • PCA requires monitoring protocol (RR, sedation score).
  • PCA requires lockout interval and close monitoring to prevent overdose.
  • Avoid basal infusion in opioid-naive patients.
  • Double-check PCA programming to prevent overdose.
  • Use preservative-free formulation for intrathecal use.

Infusion / dilution

  • Dilute to 1 mg/mL.
  • IV must be given slowly over >=4–5 minutes.

Monitoring

  • Renal function.
  • LFTs.
  • Respiratory rate.
  • Sedation score.
  • If RR <8–10/min or excessive sedation -> HOLD opioid, give oxygen, consider naloxone, urgent senior review.
  • Increasing sedation (even with normal RR) = early opioid toxicity -> HOLD and reassess immediately.
  • Sedation scale monitoring is often the earliest sign before respiratory depression.
  • Oxygen saturation.
  • Continuous pulse oximetry in high-risk patients.
  • Pain score.
  • Bowel function.

Overdose / toxicity

IF SUSPECTED MORPHINE OVERDOSE: ABC first

Recognition

  • Toxic dose is variable; opioid-naive patients are more sensitive.
  • Classic triad: miosis + respiratory depression + coma.

Immediate actions

  • Naloxone 0.04–0.4 mg IV, escalate rapidly to 2 mg if needed.
  • Start infusion at ~2/3 of the total naloxone dose required for initial reversal per hour.
  • Example: if 0.6 mg total naloxone is required for reversal, start infusion at ~0.4 mg/hour.
  • Ensure airway and ventilation while administering naloxone (do not delay naloxone).
  • Re-narcotization risk is high with longer-acting morphine exposure.
  • Airway and ventilatory support.

Antidote

  • Naloxone with repeat dosing based on response.

Decontamination

  • Consider charcoal per local protocol when appropriate and airway protected.

Escalation

  • Naloxone infusion for re-narcotization risk.

Clinical pearls

Common mistakes, resistance logic, and bedside traps

Dose ceiling

  • No ceiling dose in cancer pain (titrate with monitoring).

Constipation

  • Always prescribe a laxative with chronic use.

Bowel regimen

  • Always prescribe bowel regimen (laxative +/- stool softener).

Conversion

  • Oral:IV conversion 3:1 is critical.

Equianalgesic conversion

  • Equianalgesic conversion requires dose reduction (cross-tolerance is incomplete).

Renal risk

  • M6G accumulation is dangerous in renal failure.

Naloxone duration

  • Naloxone duration is shorter than morphine.

Opioid-induced hyperalgesia

  • Suspect opioid-induced hyperalgesia if pain worsens despite dose escalation.

Opioid-naive safety

  • Avoid ER in opioid-naive patients.

IV technique

  • Slow IV push helps reduce hypotension.

Pharmacokinetics

  • Bioavailability 25–40%.
  • Hepatic metabolism to M3G and M6G.
  • Renal excretion.
  • Oral:IV conversion approximately 3:1.

Mechanism of action

  • Full mu-opioid receptor agonist.
  • Decreased cAMP and neurotransmitter release.
  • Neuronal hyperpolarization reduces pain transmission.

Common brand names

Saudi Arabia

Morphine (generic) · MS Contin · Oramorph · MST Continus

Global

Kadian · Duramorph · Avinza · Embeda

Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Strictly controlled opioid across Gulf (special prescription required).
  • Widely used in ICU, oncology, and palliative care.
  • Limited outpatient availability in some MENA countries.
  • Oral morphine remains WHO gold standard for cancer pain.
  • Regulatory access is improving but remains restricted in parts of the region.

Saudi Arabia — confirm with local formulary.