Some commonly used medicines can make you more sensitive to the effects of heat, increasing your risk of heat stroke and other heat-related illnesses. The more of these medications you take, the greater your risk.
What can I do to protect my health this summer?
If you take any of the medicines detailed below, arrange to have a medicines review with a pharmacist, your GP or nurse. Don’t forget to include any over-the counter medicines you take.
It may not be possible for you to stop taking a medicine but reducing the dose could be an option. If a medicine is stopped or reduced, make sure to arrange a follow-up meeting with a pharmacist, your GP or nurse to review the changes.
Below are examples of medicines that can affect your body’s ability to adapt to heat.
Sweating is your body's main way of cooling down by getting rid of excess body heat. Medicines that can affect the body’s ability to produce sweat include:
- Beta blockers such as metoprolol or bisoprolol which are used for certain heart conditions and for treating high blood pressure.
- Decongestants such as pseudoephedrine (Sudafed®), an active ingredient in cold medications that are available from shops and supermarkets.
- Anticholinergic medicines, which include some shop-bought allergy medications such as diphenhydramine (Benadryl®), shop-bought sleeping pills such as Nytol®, medicines used to treat urinary incontinence such as oxybutynin and some antidepressants such as amitriptyline or nortriptyline.
Dehydration occurs when your body doesn't have enough fluids to function normally. Severe dehydration is a serious medical condition and requires urgent medical attention. You can find more information about dehydration on NHS.UK
Medicines that can increase the risk of dehydration include:
- Diuretics (sometimes known as water tablets) such as hydrochlorothiazide and furosemide, laxatives such as Senokot® or some diabetes medicines such as canagliflozin or empagliflozin which increase the elimination of bodily fluids through wee or poo.
- Some antidepressants such as fluoxetine and venlafaxine cause excessive sweating which can lead to dehydration.
Some commonly prescribed medicines interfere with the body’s ability to regulate temperature. This can make it even harder to stay cool in hot weather. Medicines that can increase your body temperature include:
- Antipsychotic medications such as olanzapine or quetiapine.
- Stimulant medications for attention disorders such as methylphenidate.
Some medicines can make you sleepy, reduce your ability to concentrate and slow your reaction time. This can affect your ability to look after your health during extreme heat, such as forgetting to drink plenty of water or staying cool. Such medicines include:
- Anti-anxiety medicines or medicines for insomnia such as benzodiazepines (lorazepam or oxazepam for example).
- Some nerve pain medications such as pregabalin and gabapentin.
- Opioid pain medications such as morphine and codeine.
If you become dehydrated and are taking certain medicines, this can decrease blood flow to your internal organs which can potentially cause damage. You can find more information about dehydration on NHS.UK
Medicines that can increase the risk of this happening include:
- Anti-inflammatory medications such as ibuprofen or naproxen.
- Blood thinners which are used to prevent blood clots.
- Medications for high blood pressure.
- Various medications used to treat diabetes, including metformin.
- Lithium for bipolar disorder.
Based on this 'Medications and heat' blog published by the Canadian Medication Appropriateness and Deprescribing Network.