The drowsy patient
Airway, sugar, drug chart and pupils. Most drowsy ward patients have a reversible cause you can fix tonight.
"Bed 17 is very sleepy and hard to wake." She is 81, day 3 after a hip fracture repair, on oral morphine 10 mg 4-hourly, regular codeine and pregabalin. RR 9, SpO₂ 93% on air, BP 112/68, pupils pinpoint. GCS 10 (E2 V3 M5). Creatinine has risen from 0.9 to 2.1 mg/dL (80 to 186 µmol/L).
What do you check first, how much naloxone do you give, and what do you change on the chart?
- Airway and breathing firstHead tilt, chin lift, suction, oxygen to target, bag-valve-mask if RR very low.
- GCS 8 or lessAnaesthetist now. The airway is at risk.
- Sugar nowBelow 4 mmol/L (72 mg/dL): treat at once.
- Pupils and focal signsPinpoint: opioids. Unequal: brain. Note the trend.
- Drug chartOpioids, sedatives, gabapentinoids, antihistamines, insulin and kidney function.
- Blood gasCO₂, pH, sodium, glucose, lactate.
- Treat the causeNaloxone, controlled oxygen and NIV, dextrose, antibiotics.
- EscalateFalling GCS, focal signs or no response to treatment.
- GCS 8 or less, or falling by 2 or more
- Unequal pupils or new focal weakness
- RR below 8 not responding to naloxone
- pH below 7.35 with high CO₂
- Fits
- Needs a naloxone infusion
- Hypoglycaemia
- Opioid toxicity from kidney injury
- CO₂ retention from too much oxygen
- Stroke or bleed (fall, anticoagulants)
- Sepsis
- Low sodium
- Hepatic or uraemic encephalopathy
- Non-convulsive status epilepticus
| GCS 8 or less | Airway at risk: anaesthetist |
| Low sugar | Below 4 mmol/L (72 mg/dL), give 150–200 mL of 10% dextrose IV |
| Opioid toxicity | RR 8 or less with pinpoint pupils |
| Naloxone (on regular opioids) | 100–200 micrograms IV every 2–3 minutes, titrated to breathing |
| Naloxone (overdose) | 400 micrograms IV, repeat as needed |
| Naloxone duration | 30–90 minutes, often shorter than the opioid |
| PaCO₂ | Above 45 mmHg (6 kPa) with low pH: CO₂ narcosis |
| Sodium | Below 120 mmol/L can cause drowsiness and fits |
Check every dose against a current drug reference and your hospital protocol.
On this page
Why it matters
A drowsy patient can be minutes from losing their airway. On the ward the common causes are reversible: opioids or sedatives (especially with poor kidney function), low sugar, high CO₂, sepsis and low sodium. Assess quickly and treat as you go.
On the phone
- GCS or ACVPU, observations, NEWS2?
- Sugar? Pupils?
- Any opioids, sedatives or new drugs in the last 12 hours? Kidney function?
- Any fall or head injury? On anticoagulants?
- Ask the nurse to put the patient in the recovery position if the airway is at risk, give oxygen to target and check the sugar.
The first five minutes
- AirwaySnoring, gurgling, vomit? Open it, suction, recovery position, adjunct if needed.
- BreathingRR, SpO₂, chest. Oxygen to target. Bag if RR below 8 and not improving.
- CirculationBP, pulse, capillary refill. Cannula, bloods.
- DisabilityGCS, pupils, sugar, limbs, neck stiffness.
- Drug chart and gasWhat was given and when? Creatinine?
- Treat and reassessGCS every 15 minutes until clearly improving.
Find the cause
- Opioids
- Naloxone, review doses, check kidneys
- CO₂ retention (COPD, obesity, sedatives)
- Controlled oxygen 88–92%, NIV
- Stroke, bleed, raised pressure
- CT head now
- Sugar, sodium, sepsis, liver, uraemia, post-ictal, drugs
- Bloods and cultures
Differential diagnosis
| Cause | Clues | First step |
|---|---|---|
| Opioids or sedatives | Slow breathing, pinpoint pupils, poor kidneys, dose increase | Naloxone, stop or reduce |
| Gabapentin or pregabalin | Kidney injury, elderly, combined with opioids | Stop; supportive |
| Low sugar | Insulin or sulfonylurea, sweaty, poor intake | Dextrose |
| High CO₂ | COPD on high oxygen, flushed, bounding pulse, flap | Venturi 88–92%, gas, NIV |
| Sepsis | Fever or low temperature, fast pulse, low BP | Sepsis pathway |
| Stroke or bleed | Focal signs, unequal pupils, anticoagulants, fall | CT head |
| Low sodium | Diuretics, vomiting, SIADH | Electrolytes; see hyponatraemia |
| Hepatic encephalopathy | Cirrhosis, flap, constipation, GI bleed | Lactulose, find trigger |
| Uraemia | Kidney failure | Nephrology |
| Post-ictal or non-convulsive status | Witnessed fit, twitching, eye deviation | EEG if available, senior |
| Hypothermia or hypothyroidism | Cold, slow pulse | Warm, thyroid tests |
Opioid toxicity on the ward
- Common when kidney function worsens (morphine and codeine metabolites build up), in the elderly, and when several sedatives are combined (opioid plus pregabalin, benzodiazepine or antihistamine).
- Give naloxone in small doses to patients on regular opioids for pain. Large doses cause severe pain, agitation, vomiting and withdrawal.
- Naloxone wears off in 30–90 minutes; long-acting opioids last longer. Repeat, or use an infusion (often two-thirds of the effective bolus dose per hour), and keep watching.
- Stop or reduce the opioid. In kidney injury, a safer opioid (for example oxycodone at a lower dose, or fentanyl in severe kidney failure) after senior or pain team advice.
A patient who wakes after naloxone can become drowsy again within an hour. Ask for observations including RR every 15 minutes for the first hour, then hourly, and a clear plan for what to do if RR falls again.
CO₂ retention
- COPD, obesity hypoventilation, neuromuscular disease, chest wall disease, and sedatives.
- Too much oxygen raises CO₂ in these patients. Don't switch oxygen off: change to a Venturi mask (24–28%), target 88–92%, recheck the gas in 30–60 minutes.
- pH below 7.35 with high CO₂ despite treatment: NIV. See oxygen and the airway.
Investigations
| Test | Why |
|---|---|
| Capillary sugar | Hypoglycaemia |
| Blood gas | CO₂, pH, sodium, lactate, glucose |
| Urea, creatinine, electrolytes, calcium | Kidney injury, sodium, calcium |
| LFTs, ammonia if liver disease | Hepatic encephalopathy |
| CBC, CRP, blood cultures | Sepsis |
| ECG | Arrhythmia, drug effects |
| CT head | Focal signs, fall, anticoagulants, unexplained drowsiness |
| Drug levels | Digoxin, lithium, antiepileptics if relevant |
Treatment
Common mistakes
- Giving 2 mg of naloxone to a palliative or post-operative patient on regular opioids.
- Forgetting that naloxone wears off before the opioid.
- Switching oxygen off in a COPD patient with high CO₂.
- Missing the sugar.
- Restarting the same opioid dose the next morning.
- Not scanning a drowsy patient on anticoagulants who has fallen.
Document
GCS and pupils, sugar, gas, likely cause, drugs held or changed, treatment and response, observation frequency, who you told.
Frequently asked questions
What is the first thing to check in a drowsy patient?
Airway and breathing, then the blood sugar. Then the pupils, the drug chart and a blood gas.
How much naloxone should I give a drowsy patient on morphine?
Small doses: 100–200 micrograms IV every 2–3 minutes, titrated to breathing rather than full wakefulness, to avoid severe pain and withdrawal.
Why do opioids cause drowsiness in kidney failure?
Morphine and codeine metabolites are cleared by the kidneys and build up when kidney function falls.
Should oxygen be stopped in a drowsy COPD patient?
No. Change to controlled oxygen (Venturi 24–28%) targeting 88–92%, check a gas, and start NIV if acidosis persists.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. An 81-year-old on regular morphine after hip surgery is drowsy with RR 9 and pinpoint pupils. Her creatinine has doubled. What is the most likely cause?
Answer: Opioid accumulation. Morphine and codeine metabolites build up in kidney injury, causing sedation and slow breathing.
- Stroke: Pinpoint pupils with slow breathing point to opioids.
- Hypoglycaemia: Check, but pupils and RR suggest opioids.
- Delirium from pain: Doesn't explain RR 9.
- Sepsis: Possible, but doesn't explain the pupils.
2. A patient on long-term opioids for cancer pain is drowsy with RR 7. How should naloxone be given?
Answer: Small IV doses titrated to breathing. Give 100–200 micrograms IV every 2–3 minutes until breathing is adequate, not full wakefulness.
- Oral naloxone: Not effective.
- 2 mg IV bolus: Causes severe pain and withdrawal.
- Flumazenil instead: Wrong drug.
- No naloxone in palliative care: Respiratory depression still needs treatment.
3. A drowsy patient with COPD on high-flow oxygen has pH 7.25 and PaCO₂ 80 mmHg. What is the cause of drowsiness?
Answer: CO₂ narcosis. High CO₂ with acidosis causes drowsiness. Controlled oxygen (88–92%) and NIV.
- Opioid toxicity: No opioid history given.
- Low sodium: Not shown.
- Stroke: Gas explains it.
- Hypoglycaemia: Not shown.
4. A patient opens eyes to pain, makes incomprehensible sounds and withdraws his arm from pain. What is his GCS?
Answer: 8 (E2 V2 M4). GCS: Eyes 4 (spontaneous), 3 (to voice), 2 (to pain), 1 (none). Verbal 5 (oriented), 4 (confused), 3 (inappropriate words), 2 (incomprehensible sounds), 1 (none). Motor 6 (obeys), 5 (localises), 4 (normal flexion/withdrawal), 3 (abnormal flexion/decorticate), 2 (extension/decerebrate), 1 (none). GCS ≤ 8 usually indicates need for airway protection.
- 7 (E2 V2 M3): Withdrawal is M4, not M3.
- 9 (E2 V3 M4): Incomprehensible sounds are V2; words would be V3.
- 10 (E3 V3 M4): Opening to pain is E2, not E3.
5. A 26-year-old man is found unresponsive. RR 6/min, pinpoint pupils, and needle marks on his arms. What is the immediate drug treatment?
Answer: Naloxone. Coma, respiratory depression and pinpoint pupils suggest opioid toxicity. Support the airway and breathing with bag-valve-mask ventilation, then give naloxone, a competitive opioid antagonist. Naloxone is shorter-acting than many opioids, so repeated doses or an infusion may be needed, and the patient must be observed.
- Flumazenil: Benzodiazepine antagonist — can cause seizures; not routine.
- Atropine: For organophosphate poisoning or bradycardia.
- Activated charcoal: For recent oral ingestions; not for an unprotected airway.
6. Which part of the brain directly controls autonomic reflexes and body temperature?
Answer: Hypothalamus. The hypothalamus integrates autonomic control: temperature, hunger, thirst, water balance (ADH), circadian rhythms and pituitary function. It acts through brainstem autonomic centres and the pituitary.
- Thalamus: A sensory relay station.
- Cerebral cortex: Higher functions; it can influence but does not directly control autonomic reflexes.
- Cerebellum: Coordinates movement.
- Basal ganglia: Control movement initiation.
7. Benzodiazepines, barbiturates and some anticonvulsants work by enhancing which neurotransmitter?
Answer: GABA. GABA is the main inhibitory neurotransmitter of the brain. Benzodiazepines increase the frequency of GABA-A chloride channel opening; barbiturates increase its duration. More chloride enters neurons, which become harder to excite. Flumazenil reverses benzodiazepines.
- Glutamate: The main excitatory transmitter; blocked by drugs like ketamine and memantine.
- Dopamine: Affected by antipsychotics and Parkinson's drugs.
- Acetylcholine: Affected by anticholinesterases and antimuscarinics.
- Serotonin: Affected by SSRIs and triptans.
References and dose sources
- Naloxone dosing: Drugs.com: Naloxone dosage (see also our naloxone dose page)
- Dextrose (glucose) dosing: Drugs.com: Dextrose dosage (see also our dextrose (glucose) dose page)
- Thiamine (vitamin B1) dosing: Drugs.com: Thiamine dosage (see also our thiamine (vitamin b1) dose page)
- Lactulose dosing: Drugs.com: Lactulose dosage (see also our lactulose dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.