Dr Fred Kavalier: A question of health

"Last year I was put on Prozac (also known as fluoxetine) for a fairly severe bout of depression. After about four months I was much better and stopped taking the drug. I have remained well for nearly a year, but now I am beginning to slide into depression again. I have asked to be put back on Prozac, but my GP has suggested another drug, sertraline (also known as Lustral), instead. I would like to know if there is any reason to choose one anti-depressant rather than another."

What's in a name?

"Last year I was put on Prozac (also known as fluoxetine) for a fairly severe bout of depression. After about four months I was much better and stopped taking the drug. I have remained well for nearly a year, but now I am beginning to slide into depression again. I have asked to be put back on Prozac, but my GP has suggested another drug, sertraline (also known as Lustral), instead. I would like to know if there is any reason to choose one anti-depressant rather than another."

Both Prozac and Lustral are members of the same family of drugs – the SSRIs (Selective Serotonin Re-uptake Inhibitors). Another commonly used drug in this family is Seroxat (also known as Paroxetine). Although the manufacturers of these drugs often try to highlight differences between the drugs in their advertising to doctors, they all work. A study of more than 500 patients last year compared the three drugs to see which was more effective. The results showed that they were all equal in their ability to treat clinical depression. Of course, some people will prefer one drug to another, for all sorts of reasons, including slightly different side effects. Seroxat, for instance, is more likely than Prozac to make you sleepy during the day. Simple things, like how easy it is to swallow the tablets or capsules, and even the colour of tablets, can also influence a patient's preference for one drug over another. Doctors, too, have their favourites. Doctors feel more comfortable with drugs they have prescribed previously. A doctor's prescribing habits may also be affected by advertising. There is no doubt that a visit from a persuasive pharmaceutical company representative can influence a doctor's willingness to try out a new drug. For you, it may be more sensible to stick with a drug that has been shown to work in the past.

Cold comfort

"I have occasionally tried to take echinacea in order to boost my immune system at the first sign of a cold. I'm not convinced that it works, but I'm prepared to take my chances if I know that the echinacea is not causing me any harm. The packet of echinacea herbal tea says that it should not be drunk by patients suffering from progressive conditions. Does that include cancer? Can anyone be sure that he has not got cancer hiding away somewhere, just waiting to be "activated" by a few doses of echinacea? I thought that conditions like asthma and hay fever result from an over-active immune system. Would echinacea make them worse?"

Echinacea is Native American plant remedy that has been used for at least 250 years. It is extracted from three varieties of echinacea plants and sold under dozens of different names. It is very popular in Germany, where it is approved for the treatment of respiratory and urinary infections. The active ingredients have been studied and there is some evidence that they affect the activity of the immune system. One of the problems in these studies is that different preparations may contain different parts of the plant and possibly different active ingredients. Nevertheless, most trials do show that echinacea taken orally can shorten the length and severity of an acute respiratory infection such as a cold. There is, as you suggest, the potential for causing problems in people who already have disorders of their immune system. There are no reported cases of cancer being activated, but it's impossible to be absolutely certain that echinacea is 100 per cent safe.

You are what you eat

"Is it worthwhile eating Benecol as a way of reducing my cholesterol?"

Benecol, and a similar product marketed under the name of Flora pro.activ, both contain chemicals called stanols and sterols that are derived from plants. They were originally sold as margarines, but have now also been incorporated into other dairy products. These stanols and sterols can reduce the level of cholesterol in the bloodstream by up to 20 per cent if you eat the recommended amount of them. They probably do this by reducing the amount of cholesterol that is absorbed by the intestine. It is important to remember that cholesterol levels are just one risk factor for heart disease. Smoking, lack of exercise, high blood pressure and obesity are other important factors. I am hesitant to recommend using Benecol or Flora pro.activ because we do not yet know for certain if it will prevent heart disease.

Have your say

Last week's question about cystitis provoked a large number of suggestions from women who have suffered from it.

JH writes: The following remedy is totally disgusting but really works. At the first sign of an infection, buy some natural yoghurt, bicarbonate of soda and heavy-duty sanitary pads. Lots. Drink half a pint of water with one teaspoon of bicarb of soda dissolved into it every half an hour. It's unpleasant, but stick with it. Stuff as much plain yoghurt up your vagina as you can (use clean fingers). You need the sanitary towels, because you will leak. Re-apply after every visit to the loo. Forget about going to work or shopping while doing this. Drink only water for a few days, but plenty of it. In 24-48 hours you should have it beaten.

CA writes: I have been symptom-free for almost a month (the longest period for several years), after reading Cystitis by Angela Kilmartin (Thorson's, £6.99). The author essentially advocates "bottle-washing" the genital and anal area very carefully after excreting and both before and after sex. It works for me.

Please send your questions and answers to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax to 020-7005 2182 or e-mail to health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions