It is almost two months ago to the day since I had my operation. As is common in men of my age, my prostate had grown uncomfortably large and was in need of a trim. The operation went well, but the immediate post-operative weeks brought some challenging moments when I contracted two bacterial infections that required antibiotics. And there was more – during my convalescence I made an unexpected discovery; I realised that the tiredness I had felt for years and had believed was part of the ageing process was, in fact, due to poisoning. Put more conventionally, I had been subjected to an unsuspected side effect of tamsulosin, a drug that I had been taking for the treatment of my enlarged prostate for over a decade. Faced with these various insults to my body, I gained a new insight into one aspect of how I tick – my feelings towards infections and to poisoning are very different.

While the infections were worrying, my concerns were eased partly by my sneaking respect for bacteria, a sentiment that probably stems from my years as a doctor. As I see it, humans and bacteria have much in common. Planet earth has been our shared home for millions of years and, like us, bacteria have struggled to survive. While most of them leave us alone or even support our interests, others have evolved to cause harm. With few exceptions, the harmful varieties can be identified, are known by name and, when going about their business, follow recognised ‘biological’ rules of engagement. To keep them at bay, we – and other mammals – have developed ingenious, and often precisely-targeted, defence mechanisms; for their part, bacteria have evolved ways to neutralise our endeavours.

Through a mixture of immunisation, antibiotics, simple hygiene and our natural defences, the balance between bacteria and humankind is, for the time being, tipped in our favour and for me, bacteria remain acceptable planetary co-habitees. I was certainly not angry with the bacteria that caused my infection – a feeling quite unlike the resentment that I experienced on discovering how for years I had been poisoned.

The poisoning revelation came one evening after I had phoned Robert, a close friend just recently turned 83. His companion Robin answered the phone and suggested that I ring back slightly earlier next day. She explained that “Robert is older now and goes to bed soon after supper – these days he needs more sleep”.

I knew exactly what she meant. Although I am eight years Robert’s junior, daytime sleepiness had also become a regular part of my life. It was, I assumed, natural for someone of my age and worryingly, it could only get worse. Siestas were taken most days, and dozing while watching the Ten o’clock News – the 10 o’clock ‘Snooze’ as it became known – was standard. And there were more serious lapses with moments of tiredness when driving; on one occasion, falling asleep nearly killed me (‘Après le déluge, moi’. Greyhares, September 5, 2012). In recent months I had decided that one hour at the wheel was a realistic safe maximum.

With Robin’s comment fresh in my mind I suddenly realised that, since my operation and no longer taking my ‘prostate’ medicine, my drowsiness had practically stopped. During that very afternoon I drove for hours without feeling sleepy and a week had passed since my last afternoon nap. I should have guessed the reason, after all, for forty years I had worked as a clinical pharmacologist, a discipline specialising in understanding medicines and how they worked. I did an internet search, and there it was in print: – ‘Common side effects of tamsulosin include drowsiness – be careful if you drive or do anything that requires you to be alert’. As if to confirm my suspicion, the symptom had worsened recently after the dose was doubled; quod erat demonstrandum.

It would be facile to claim that drug-induced poisoning is unusual. Thousands of people with cancer, for instance, suffer horrible side effects from chemotherapy and they certainly experience it as poisoning – a poisoning so serious that many hundreds of recipients are killed by it each year. In fact, the poisonous side effects of medicines generallprobably kill more people than the tens of thousands who succumb each year to the nitrogen dioxide or diesel micro-particles spewed out by street traffic pollution.

Poisons, unlike bacteria, seem cold, indiscriminate and alien. While I did not like being infected, it was anger I felt when I realised that I had been poisoned by a medicine that I had been taking willingly for years, and which had covertly cheated me into feeling and acting older. Users of medicine should beware. In my case the villain was tamsulosin, but all medicines have the capacity to poison. The lesson is ‘be vigilant’.

Not wishing to end on too gloomy a note, I should add that my new plumbing arrangement works like a dream.