Heat-related illness is an increasingly relevant clinical concern for UK pharmacists. According to UKHSA's Heatwave Plan for England, the frequency and intensity of UK heatwaves have increased measurably over the past decade, and community pharmacies — as accessible, walk-in healthcare venues — are often the first place patients or their companions seek help when symptoms develop.
Heat Exhaustion vs Heatstroke
These are two points on a spectrum of heat-related illness, and distinguishing between them is critical because heatstroke is a medical emergency.
| Feature | Heat exhaustion | Heatstroke |
|---|---|---|
| Body temperature | Below 40°C | 40°C or above |
| Skin | Cool, pale, clammy, heavy sweating | Hot, dry, flushed, sweating may stop |
| Mental state | Alert but fatigued, may be dizzy | Confused, agitated, may lose consciousness |
| Other symptoms | Headache, nausea, muscle cramps, fast pulse | Seizures, rapid breathing, organ dysfunction |
| Pharmacy management | Appropriate with close monitoring | Call 999 immediately |
The key differentiator is mental state. A patient who is confused, disoriented or unresponsive has likely progressed beyond heat exhaustion into heatstroke and requires emergency medical attention.
Pharmacy First Aid for Heat Exhaustion
When a patient presents with or develops heat exhaustion symptoms in or near the pharmacy, the following steps should be taken:
1. Move to a cool environment. Bring the patient inside the pharmacy or into a shaded area. If the pharmacy has air conditioning, this is ideal.
2. Lie down and raise the legs. This helps restore blood pressure if the patient is feeling faint.
3. Remove excess clothing. Jackets, scarves and tight clothing should be loosened or removed to allow heat dissipation.
4. Cool the skin. Apply cool (not ice-cold) water to the skin using a spray bottle or damp cloth, focusing on the neck, armpits and groin where large blood vessels sit close to the surface. A fan directed over damp skin accelerates evaporative cooling.
5. Rehydrate. Offer sips of cool water. Oral rehydration salts (Dioralyte or equivalent) are preferable to water alone as they replace sodium and potassium lost through heavy sweating. Sports drinks are an acceptable alternative.
6. Monitor. The patient should begin to feel better within 30 minutes. If symptoms do not improve, or if the patient's condition deteriorates — particularly mental status — call 999.
OTC Products for Heat-Related Illness
Pharmacists can supply and recommend several products:
Oral rehydration salts
ORS sachets (Dioralyte, O.R.S. tablets) dissolved in cool water are the gold standard for rehydration after heat-related fluid and electrolyte loss. They are inexpensive, effective and safe for all ages. One sachet in 200ml of water, sipped over 30–60 minutes, is the standard approach.
Paracetamol
Paracetamol can help manage headache associated with heat exhaustion. However, it does not lower body temperature in heat-related illness the way it does in fever from infection — the thermoregulatory mechanism is different. It remains useful for symptom relief but should not be relied upon as a cooling measure.
After-sun and cooling products
Aloe vera gel and calamine lotion can soothe skin that has been sun-exposed alongside heat exhaustion. These provide comfort but do not treat the underlying systemic dehydration.
At-Risk Groups
Certain populations are at higher risk of heat-related illness, and pharmacists should be proactive in offering advice during warm weather:
- Elderly patients — reduced thirst sensation, impaired thermoregulation, often on multiple medications
- People taking diuretics — accelerated fluid loss
- Patients on anticholinergics — reduced sweating capacity (oxybutynin, amitriptyline, hyoscine)
- Those on beta-blockers — impaired cardiovascular response to heat stress
- People with chronic conditions — heart failure, COPD, diabetes, renal impairment
- Outdoor workers — prolonged exposure without adequate breaks
- Infants and young children — immature thermoregulation
Pharmacists conducting medication reviews during summer months should flag patients whose medication profiles increase heat vulnerability and offer targeted advice on fluid intake and cooling strategies.
Prevention Advice
Proactive pharmacy advice during warm weather can prevent heat-related presentations:
- Drink water regularly, not just when thirsty — aim for 6–8 glasses per day, more in hot weather
- Avoid alcohol and caffeine during heatwaves, as both promote diuresis
- Stay indoors during peak heat (11am–3pm)
- Wear loose, light-coloured clothing and a wide-brimmed hat
- Use sunscreen (SPF 30+, reapplied every 2 hours) to prevent sunburn, which impairs the skin's cooling capacity
- Close curtains on south-facing windows during the day
- Never leave anyone in a parked car, even briefly
When to Call 999
Heatstroke is a medical emergency with a mortality rate that increases with every minute of delay in cooling. Pharmacists should call 999 if a patient in or near the pharmacy:
- Has a body temperature of 40°C or above (if a thermometer is available)
- Is confused, disoriented or unresponsive
- Has stopped sweating despite being hot
- Is having seizures
- Has not improved after 30 minutes of cooling measures for heat exhaustion
While waiting for the ambulance, continue active cooling: remove clothing, apply cool water, fan the patient, and place ice packs (wrapped in cloth) in the armpits and groin.
Pharmacy Preparedness
Pharmacies in areas with high elderly populations or outdoor worker footfall should consider seasonal preparedness during warm months, including visible display of ORS products, cooling sprays and sunscreen, along with printed heat-safety advice leaflets from UKHSA.
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