Heat Intolerance and Medicines

Did you know medicines are one of the most common causes of heat intolerance? This summer we have seen temperatures go above 30°C in some regions of New Zealand. As many people get out to the beach, walk in the park, and enjoy the summer festivities, those with heat intolerance may be feeling frustrated and uncomfortable. In this article we will look at how your medicines may affect your heat tolerance, and how to manage the warm weather.

Heat Intolerance and Medicines

For some people moderately warm or hot weather can result in them experiencing a range of uncomfortable symptoms. This can occur at temperatures where other people may feel completely comfortable. Typically, when you need to cool off the hypothalamus (a part of your brain) will tell your body to sweat – which cools your body down as it evaporates off your skin. However, if your body is not regulating its temperature properly you may experience the symptoms of heat intolerance. These symptoms may include excessive sweating, exhaustion, fatigue, nausea, dehydration, dizziness, vomiting, and mood swings.

Medicines are one of the most common causes of heat intolerance. Certain medications can affect your body’s ability to regulate temperature. Here are some of the ways medication can affect your heat tolerance:


  • Some medicines directly raise your body temperature by acting on the hypothalamus.
  • Your blood flow to your skin can be decreased, preventing heat from leaving the body from the surface.
  • Certain medication can cause dehydration, making you more susceptible to heat intolerance.
  • Medicines may impair your ability to sweat, making it harder for your body to lose heat.
  • Some medicines may decrease your thirst sensation, this increases the risk of dehydration and heat intolerance.
  • Medications can also make the skin more sensitive to the sun and increasing risk of sunburn and heat intolerance.

Here are some common medications that may make it harder for your body to handle increased temperatures and cause heat intolerance:


  • Blood pressure medications (such as thiazide diuretics and beta blockers)
  • Psychiatric medications (antidepressants, antipsychotics)
  • Stimulant Medications for ADHD (such as Ritalin)
  • Anticholinergic (often prescribed for overactive bladder and Parkinson’s disease)
  • Antihistamines
  • Decongestants
  • Dopaminergic medication


If you have started to notice the symptoms of heat intolerance or have questions about your medications and heat intolerance, you should speak to your doctor or pharmacist.

If you are struggling with the heat this summer and think your medicines may be contributing to this it’s very important you don’t abruptly stop taking your medicines.  Always talk with your doctor or pharmacist if you are concerned. There are also some effective ways to manage heat intolerance that can help you this summer:


  • Where possible avoid spending prolonged periods in direct sunlight, especially during the hottest parts of the day.
  • Stay hydrated, it is helpful to carry water with you and drink it regularly.
  • Wear loose fitting, lightweight and light-coloured clothing.
  • Wear a hat with a wide brim or with flaps covering the ears and neck.
  • Avoid exerting yourself physically during hot weather, or in direct sunlight.
  • Use air condition or a fan indoors to stay cool.


If you begin to experience the symptoms of heat intolerance sit down somewhere cool indoors and drink a glass of water. Wrapping a towel soaked in cold water around the back of the neck, or taking a cool bath can help to relieve symptoms too. If symptoms don’t subside despite you taking steps or you are concerned it may be worth seeking medical advice or attention.

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