Warning to millions who take antihistamines, cold pills and metformin

There are five ‘behaviour’ symptoms to watch for as the side effects can be serious

Health experts have issued a warning to millions of people who take common medications – many of them over the counter – for everything from colds and allergies to heart disease and diabetes. Elderly care experts have issued a warning over combinations of medications that could put people at risk of serious side effects.

A Nuffield Trust study found that only 41% of people said they were “definitely” informed about side effects of the medication they’re taking, with 30% stating they were not told at all – even though almost two million over-65s take at least seven prescribed medicines per day.

Lee Cartwright, expert at Mobility Solutions Direct, shared the most concerning medication combinations that older people and others need to watch out for.

1. Furosemide and Indapamide (heart condition medications): “Medications prescribed for heart conditions such as heart failure or high blood pressure, like furosemide or indapamide, can cause sudden drops in blood pressure, meaning patients need to maintain consistent hydration. For older people, this can become risky quite quickly. If, for example, someone taking these tablets begins sweating more than usual, their blood pressure can fall sharply, raising the likelihood of dizziness and falls.”
2. Metformin (Type 2 Diabetes) + Furosemide (heart): “Metformin, a common treatment for Type 2 Diabetes, can cause a serious condition called lactic acidosis if the patient becomes dehydrated. Symptoms include extreme tiredness, muscle pain, nausea and cramps. When metformin is taken alongside heart medication such as furosemide, the risks are heightened, particularly in older patients, as dehydration can quickly make them more vulnerable to falls.”
3. Antihistamines (hay fever) + Benzodiazepines (anxiety/sleep): “Many hay fever medications contain antihistamines, which are effective for easing symptoms but are also known to cause drowsiness. If older Brits are already unsteady on their feet, combining these with other sedating medications can increase the risk of falls. Benzodiazepines such as temazepam, diazepam and nitrazepam, which are commonly prescribed for anxiety or sleep problems, can add to drowsiness and confusion. Using these medications together should therefore be approached with care.”
4. SSRIs (antidepressants) + Decongestants (cold/flu): “Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, sertraline or citalopram, are widely used to treat depression and anxiety. However, they can sometimes lead to drowsiness, slower reactions and confusion. When combined with decongestants found in cold and flu products, like pseudoephedrine or phenylephrine, they can also affect blood pressure, sleep and mood. Without proper monitoring, this interaction may result in unusual behaviour that can be distressing both for the patient and those around them.”
5. Multiple medications (SSRIs, sedatives, antihistamines): “When confusion and slower reactions set in, the risks to a person’s safety rise considerably. They may misjudge their environment, take unnecessary risks, or, in more severe cases, fail to recognise or treat injuries. This danger is particularly acute for people living with dementia or Alzheimer’s, as medication side effects can add to existing vulnerabilities.”

What to do if you experience side effects

Lee said: “Medication-related confusion may cause sudden changes in behaviour such as irritability, aggression, altered personality, rambling speech, or difficulty concentrating. Keep a careful eye on those showing these symptoms, as they may be more vulnerable to accidents.

“Practical steps within the home can greatly reduce these risks. Checking for hazards such as loose rugs, poor lighting on stairs, or slippery floors is essential. Simple measures, like securing rug edges with tape, installing non-slip mats in bathrooms and kitchens, and improving visibility, can have a significant impact on safety.

“While the prospect of falls can understandably be worrying, the key point is that straightforward, preventative action can make all the difference. By addressing these risks early, older adults can remain safe and independent in their own homes for longer.”