I am healthy and active, but I cannot stop going to the toilet. Will the medication I use give me dementia? Dr. Martin Scurr answers

I am a healthy, active 70-year-old, but in the past three years I have taken tolerodine every day to treat an overactive bladder. I read that it is linked to dementia. Do I have to worry?

Anne Birch, Oxfordshire.

Dr. Martin Scurr answers: You are right, there are worries that a number of different types of medicines are known as anticholinge, which means that they block the functioning of a chemical messenger in the brain, called acetylcholine.

This chemical is important for maintaining, for example, memory and attention span.

Any reduction in acetylcholine can influence the way in which nerve cells are behaved in the brain the concern about whether long-term use of such medicines can increase your risk of dementia. In addition to those prescribed for bladder problems and incontinence, some antihistamines have this anticholinergic effect – as well as certain antidepressants (such as amitriptyline).

The risks seem to occur with sustainable use of these drugs – for more than three years, according to research.

For my female patients I recommend vaginal pessaria that contains estrogen (vagifem) – even in patients who are past menopause – because they are effective in reducing urinary tract problems and I believe that such an approach will also free you from symptoms, without being needed to take tolerodine.

I have osteoarthritis in my left knee and need a replacement joint soon. But I am allergic to the nickel and cobalt, which I know they are being used in implants. Is there an alternative?

Carol Lewis, Exeter.

Dr. Martin Scurr answers: Patients with a confirmed nickel or cobalt allergy must indeed avoid orthopedic implants as standard cobalt chromium used for joint replacement.

These types of implant can release metal particles or ions in the body. In some people this can cause a delayed hyper -sensitive reaction, such as skin rash or poor wound healing.

It is not uneven how certain jewelry with these metals cause an eczema -like reaction in some people.

But these metals not only cause skin reactions – in joint replacements they can cause a deep tissue reaction in sensitive people.

For example, if a metal implant in the knee is used, the particles that release the immune reactions can cause swelling and tissue to death. In turn, these reactions can lead to failure of the implant and the need for overhaul surgery.

Patients with a confirmed nickel or cobalt allergy should avoid orthopedic implants as standard cobalt-chromium

Although it is important to emphasize that standard implants of these metals are driven well in most patients, if there are inexplicable pain, swelling or loosening of the implant, and no infection or other explanation dan can be considered an allergic reaction as the cause.

Patients are routinely asked in advance if they have an allergy to the metals used, and hypo-allergenic (or allergen-free) implants are available. They are usually made with titanium or ceramic materials.

I recommend discussing the case with your specialist and possibly looking for an up-to-date revaluation by an allergy expert before your orthopedic consultant decides which joint you should use in your case.

Your specialist can also be able to offer nitride coated implants (metal, but with a special coating) or oxinum implants (a metal core but with a ceramic surface), both reduce the release of metal ions.

In general, this is a matter of very careful consideration before continuing with a procedure. If allergy tests reveal that you are allergic to those metals, it is important that this is noticed in your medical records.