Reasoning GP · Algorithm · 1-page summary
Excessive daytime sleepiness — adults
For: adults who doze or struggle to stay awake in the day. Not for: children; tiredness without dozing (use the fatigue algorithm); poor night sleep as the main problem (insomnia algorithm).
Core rule: separate acute drowsiness (an emergency) from chronic sleepiness, and give the driving advice today — sleepiness that affects driving means no driving until it is controlled.
0Stop — call 999 now — acute drowsiness is not sleepiness
- New drowsiness over hours to days with confusion, headache, fever, neck stiffness, focal signs or vomiting → 999
- Several people at home drowsy or with headaches → possible carbon monoxide: leave the property, 999
- Unconscious or fitting with hypoglycaemia → 999
1Triage — sleepiness or fatigue, and timing
| Picture | First move |
|---|---|
| Short sleep on work days | Insufficient sleep — extend and regularise sleep |
| Snoring, apnoeas, obesity | OSA — STOP-BANG, Epworth, sleep service |
| Night or rotating shifts | Shift-work or circadian problem |
| Cataplexy, sleep paralysis | Narcolepsy — neurology or sleep medicine |
| Tired, not dozing | Fatigue pathway |
2Screen — one row is enough
- Breathlessness, morning headache, cyanosis, ankle swelling, low resting SpO₂ → hypercapnic failure Same-day
- Hypoglycaemia on insulin or a sulfonylurea → glucose, treat Same-day
- Falling asleep at the wheel or a near miss → stop driving now, document, expedite referral Same-day
- Group 2 driver or safety-critical worker with sleepiness → expedited sleep service Urgent
- Sudden sleep attacks on a dopamine agonist → no driving, review medicine Urgent
- Low mood with suicidal thoughts → crisis Same-day
3Assess — scores support, history decides
☐ Sleep on work days and days off; 2-week sleep diary ☐ Partner account: snoring, apnoeas, kicking ☐ Sedating medicines, alcohol, cannabis ☐ BMI, neck, BP, airway, thyroid, SpO₂ ☐ Epworth (above 10 excessive) and STOP-BANG (3 or more raises OSA risk) ☐ Licence group, occupation
Bloods by indication: FBC + ferritin, TSH, HbA1c, U&E, LFTs. Sleep studies are arranged by the sleep service.
4Classify — only if the screen is negative
- Insufficient sleep (commonest) — catch-up at weekends.
- OSA — 2+ features (NG202) → sleep service.
- Drugs or alcohol — sedatives, gabapentinoids, opioids, antihistamines → reduce or re-time.
- Depression, hypothyroidism, anaemia, diabetes, restless legs → treat the cause.
- Narcolepsy or hypersomnia → neurology or sleep medicine.
- Uncertain — sleep service after the primary-care work-up.
5Treat today — doses: NICE/SPC, BNF, local formulary
- Driving today: must not drive while sleepiness affects driving; suspected or mild OSA — notify the DVLA if not controlled within 3 months; moderate or severe OSA or narcolepsy — must notify. Document.
- Suspected OSA: refer; weight loss, less evening alcohol, avoid sedatives, side sleeping.
- Sleep: 7–9 hours for most adults; regular times; protected sleep after night shifts.
- Do not start modafinil or other wake-promoting drugs in primary care.
6Refer routinely
- Suspected OSA with 2+ features, or unexplained sleepiness → sleep service.
- Suspected narcolepsy, idiopathic hypersomnia, REM sleep behaviour disorder → neurology or sleep medicine.
- Weight management; occupational health for shift work; drug and alcohol services.
7Never reassure by
- A low Epworth score when the history describes dozing at the wheel.
- "Just snoring" without asking about apnoeas and sleepiness.
- Fatigue and sleepiness treated as the same complaint.
- Leaving driving advice until the sleep study result.
- Sedatives for poor sleep in suspected OSA without caution.
- Missing carbon monoxide when the household is affected.
8Safety-net — say it, then document it
999 “Call 999 for sudden drowsiness with confusion, severe headache, weakness or fits — or if several people at home are drowsy or have headaches: leave and call 999.” Same-day “Contact us today if you get breathless, swollen ankles or blue lips. Don’t drive while you feel sleepy — not until it is controlled; we will guide you on telling the DVLA.”
Follow-up: 2–4 weeks — results, sleep diary, Epworth; re-check driving at each contact.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Sleepiness distinguished from fatigue
Medicines, alcohol and sleep quantity reviewed
Driving advice given and documented
Referral and review date set
Summary of the full Reasoning GP excessive daytime sleepiness algorithm, which holds the detail, examination, investigations and evidence. Sources: NICE NG202, TA139; DVLA Assessing fitness to drive; NICE CKS; MHRA; UKHSA. Clinical reference — follow local pathways and check doses in the current SPC, BNF and local formulary.