Medications and Summertime Heat

Several medications commonly prescribed for older adults can affect them in the heat,  creating an increased risk  of developing heat stroke or heat exhaustion.  As a result, older adults on these medications need to know how to "keep their cool."


Type of Medication Why They Can Cause Problems for an Older Adult


Examples, or specific drugs to watch out for
 Beta Blockers
















Anti-parkinson drugs 

Beta blockers are used to regulate high blood pressure by keeping the heart rate low. These drugs don't allow the small blood vessels in the skin to dilate. That reduces blood
flow to the skin  and impedes sweat production and causes the body temperature
to rise.

The human body needs to respond to heat stress by elevating heart rate and dissipating the heat. Beta blockers work against that system and predispose people working in heat to heat-related emergencies. Diuretics and calcium channel blockers have similar effects by working against the body's protective systems.


Anti-parkinson drugs inhibit perspiration




Inderal or Betapace.















e.g. Sinemet




Antidepressants can cause sedation and dizziness, so the person may be less aware of heat problems.

Some increase heat production, so the person's body is warmer.

Tricylic anti-depressants affect body's ability to regulate heat.

Lithium heavy exercise or heavy sweating in hot weather may change lithium levels, so that you

may have too much in your system.





Tricyclic antidepressants, such as Elavil or Sinequan.



Monoamine oxidase inhibitors (MAOIs), such as Furoxone or Nardil.



These drugs reduce sinus congestion by
blocking the function of the autonomic nerves. But this
group of nerves stimulates your sweat glands. So a side effect of the antihistamines is that you produce less sweat. You need to sweat to keep  your body cool.



e.g. Benadryl, Chlortripolon

Doctors say don't stop taking antihistamines, if you suffer from allergies. They say you should just drink plenty of water when you do take them.


Over-the-counter sleeping pills


Some contain the same medication  that is used in antihistamines [see above].

Also causes sedation, you may not be aware of how hot you are.



e.g. Nytol


Anti-diarrhea pills


Can cause confusion, dizziness for some.

e.g. Lomotil






Some diuretics  (usually used as a hypertension medication)




These drugs make you lose water, and increase  your urine flow and as result you lose salt too. You need isotonic fluids to replenish
the lost minerals.

Can make you feel light headed when you get up quickly or exercise.

Some diuretics make you sensitive to sunlight.





Psychiatric drugs


Some neurolepics such as Haldol alter the person's sense of thirst (so, the person may not realize her or his body needs the water)

Some of the drugs used  for schizophrenia sedate the person.

Some of the newer neuroleptic medications ("atypicals") have been fund to weaken the heart muscle,  leaving the person more susceptible to heat problems.









Occurs when a person's body is not able to regulate its temperature regulation properly and the body's temperature rises to critical levels. This is a medical  emergency.



An extremely high body temperature (above 103F); red, hot, and dry skin (no sweating); rapid, strong pulse;  throbbing headache; dizziness; nausea; confusion; unconsciousness








Is caused by an imbalance of water/electrolytes




Heavy sweating; paleness; muscle cramps; tiredness; weakness or fatigue; dizziness; headache; nausea or vomiting; fainting.







Take in adequate water/fluid/electrolyte replacement and avoid fluids that contain caffeine or alcohol




Are caused by water and/or electrolyte depletion. Heat cramps are usually a precursor to heat exhaustion and heat stroke.



 Painful muscle spasms



  Stretching, coupled with water and electrolyte replacement





Center for Disease Control. Frequently Asked Questions for Extreme Heat. Online:

Warning: Heat Exhaustion & Allergy Sufferers. Online at:

Yale New Haven Health. Medications that increase the risk for a heat-related illness. Online at:

York, K. (August, 2000) "Consumers: Take care in the heat." Interface. Online at:

Zoghby, J.C. (Jul. 22, 1995). Medications can magnify heat dangers: Special warnings given for older people. Mobile Register, Section: 1B, 6B Online at :


Page last updated: 31/10/2004

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