DR MARTIN SCURR: Will taking antihistamines do me long-term harm?

I’ve had problems sleeping for years but taking an antihistamine tablet (cetirizine) a couple of nights a week really helps. But the pills leave me a bit groggy, and could they do me any harm?

Tina Vowles, Gloucestershire.

Dr Martin Scurr replies: Antihistamines target histamine receptors. Histamine is a chemical that the body produces in response to a perceived threat (in the case of an allergy, wrongly perceiving a harmless substance as a threat). The symptoms are the body’s way of trying to get rid of it (such as sneezing).

But histamine also plays a role in wakefulness, so an antihistamine can make you feel sleepy.

However, not all antihistamines are the same. There are two types: sedating and non-sedating.

The former are better able to cross into the brain (thanks to the way they are carried in the blood) – these include chlorphenamine (brand name Piriton).

The cetirizine you’re taking is non-sedating, although some people find that it makes them sleepy, and you seem to be among their number.

The long-term use of antihistamines has been linked to dementia. It’s important to point out that it’s not a proven cause, but the risk seems to be because some antihistamines are anticholinergics.

This means they work on receptors in the brain that respond to the chemical messenger acetylcholine: low acetylcholine levels are characteristic of dementia.

Long-term use of other drugs that block these receptors, which include antipsychotics and some antidepressants, is also linked to a raised risk of dementia.

In fact cetirizine is a weak anticholinergic, so your twice-weekly doses aren’t a concern, though it’s not good to feel groggy.

My advice would be: limit the pills, go to bed only when sleepy, get up if you are unable to sleep, don’t read or watch TV in bed – it is for sleep only, rise at the same time every morning and don’t nap during the day.

I was diagnosed with a calcaneal spur on my heel following an X-ray. My GP referred me to a podiatrist – I am awaiting an appointment but I am in great pain. I use chiropody felt and heel supports in my shoes, but this isn’t alleviating the discomfort.

Owen Rees, Devon.

Dr Martin Scurr replies: Calcaneal, or heel spurs, are bony growths on the calcaneus, the heel bone. These can be symptomless and are often spotted during an X-ray given for other reasons. They can also be acutely painful, even disabling.

They develop as a result of long-term stress on the ligaments in the foot – for instance as a result of gait abnormalities, poorly fitting shoes, carrying excess weight, osteoarthritis or plantar fasciitis (inflammation of the tissue that connects the heel bone to the ball of the foot).

This causes inflammation, which the body responds to by building up bone as a protective mechanism. Treatments include padding – the heel supports may not be helping much, but a podiatrist will be able to provide a superior version, in the form of orthotic insoles.

Your GP may also prescribe a non-steroidal anti-inflammatory drug (NSAID), such as diclofenac. You should persevere with this treatment for at least six weeks. The next stage is a corticosteroid injection, usually administered using ultrasound to locate the problematic area precisely. But note, this is given to suppress inflammation, rather than to eliminate the spur itself.

An orthopaedic specialist may suggest Botox injections to ‘paralyse’ the muscles in the sole, taking the pressure off the inflamed area so it can heal.

In extreme cases patients may be offered surgery to remove the spur, although the majority find their pain is resolved by more conservative methods, and the case for surgical intervention remains unproven.

I’d warn against other experimental treatments, including shockwave therapy and ultrasound – which are widely advertised for this kind of problem, but in my view are a waste of money.