There exists in the Hepatitis C treatment world a standard myth that patients should drink plenty of water. This document explores the myth.

The case for:-

1. Patients undergoing treatment perspire more, and require more fluid to make up for this.
2. Treatment causes de-hydration which requires extra fluid intake.
3. Toxin build-up in the body is reduced by extra fluid intake.
4. Treatment side-effects are reduced by extra fluid intake.
5. Everybody recommends it, and it can't do any harm.

Sounds open-and-shut doesn't it? It is not quite as simple as it sounds.

Drink extra fluid to counter perspiration loss and dehydration?
In my view this is only true to a point. Unless doing heavy work in a high temperature environment the human body looses very little fluid by perspiration. The normal thirst sensation adequately controls fluid intake to balance the losses, and does not need to be overridden. Any small excess is just excreted harmlessly, so a small excess can be regarded as safe, and possibly beneficial.

Toxin build-up is reduced?
There is no scientific evidence for this whatsoever. The function of the liver and kidneys have been studied for many years and there has been no documented evidence that drinking extra water can have this effect. It is one of the more interesting pieces of pseudo-science that everybody can understand the concept of washing something with water to remove dirt, and people tend to assume that the function of water in the body is the same. Wash something with plenty of water and it will become clean. It is a simple concept but unfortunately innaccurate. The real mechanisms are far more complex but let us just follow the 'washing' analogy for a moment. Both ribavirin and interferon are toxins, and if you attempt to flush out other toxins you will take these with them. This is a vast simplification which probably only holds good for interferon, but it does make the point. Staying with the washing analogy, there are an awful lot of substances in the body which are not toxins, and are required for normal life. Washing will 'remove the baby with the bath water' and lead to an overall negative effect.

So lets forget the analogy and look at some real science. When you inject interferon into your body, it distributes through the fluids in the body. Very little goes anywhere else (unlike ribavirin). The average body has about 10 litres of fluid, so the dose slowly distributes into this volume. The old-fashioned interferons used to distribute very quickly, which caused problems as they tended to be gone before they could have enough effect. Nearly all interferon, new and old, is excreted unchanged by the kidneys. The newer pegylated interferons have a molecular 'tail' added to them which slows this down and makes them more effective, but even so the concentration of drug in your blood varies by a ratio of two to one during the week. The 'tail' is polyethylene glycol (PEG) which is very soluble in water. (You prove this regularly - PEG is used in many hair shampoos and detergents - look on the bottles!) So what happens if you start to push extra water into the system? Firstly, the volume of fluid in your system increases. It has to, as the only route to your kidneys where it will eventually be removed is via your bloodstream. This means that the volume that the interferon is diluted into goes up, and the concentration drops. Bear in mind that it already drops to half its peak value just before each injection. How much further does it have to drop before it becomes ineffective and the virus starts to breed rather than die? There is also the solubility factor. Interferon and polyethylene glycol are very soluble in water. Pegylated interferon has a half-life of about 80 hours, in other words your body clears half of it via your kidneys in that time. These figures assume that you drink normal quantities of fluid. If you push extra fluid through you kidneys you are very likely to increase the rate at which the interferon in your system is excreted. There is a strong possibility that the reason why patients feel better when drinking excess water is that it is reducing the concentration of the interferon and thus its side effects. Needless to say it is also reducing the chances of a cure. The problems don't stop there. As the fluid volume in your body increases it causes red cells in your bloodstream to swell up. This is a well documented phenonenon that occasionally occurs in hospitals when drips are poorly monitored. Eventually the red cells burst and die leading to anaemia. This is exactly the same type of anaemia that is caused by ribavirin treatment. On the basis that the ribavirin is giving your red cell count a hammering do you want to risk making the situation worse? The chances of voluntarily drinking sufficient fluid to cause problems are probably remote, but why take the risk? The additional water in the system also has another effect in that more diluted blood has to be pumped through any organ to supply it with oxygen than normally, and the heart has to work harder. This will probably increase 'short-of-breath' and heart-pounding symptoms.
One of the classic symptoms of over-hydration is swollen ankles. If you get this it may be because you are over-doing the fluids, and you should see a doctor regardless. As a final point, remember that the mechanism that caused the death of Leah Betts and other ecstacy casualties was too much water causing brain swelling. The brain, being encased in bone, has no space to swell up, and the pressure inside the skull rises constricting blood flow and causing death. This is an extreme case, but just bear in mind that it is possible.

Despite extensive research I have yet to find any valid documentation that promotes drinking extra water. You would have thought that the drug manufacturers would have included it in their data sheets if it was beneficial, but they don't. Neither do any reputable clinical sources. Well-meaning sources often suggest it, but cannot produce any documentry evidence as to the reason, benefits or safety of doing so. My contention is that it is a myth, and a dangerous one! At best it may make you feel better at the expense of your chances of a cure. At worst it can be hazardous. Next time someone suggests to you that drinking extra water is a good idea, challenge them to produce proof, or at least justify the statement. Then let me know the result, as would be delighted to hear. This is one situation where I would be happy to be proved wrong! If you feel strongly about it research it yourself and let me know your conclusions. I stand to be corrected!

So how much water is required? The simple answer is that human beings have a simple correctly-scaled-for-body-size measuring system built in. Its called a bladder. If you are emptying a full bladder four or five times a day then you are getting sufficient fluid. The beauty of this advice is that it takes into account all the variables, perspiration losses, etc and works for everyone. If anyone is seriously concerned about dehydration, get you doctor or nurse to show you the 'pinch' test. It is simple and will reassure you.