lmorin
Contributor
Rehydration cannot be accomplished by tablets of any kind. It takes water, as you have noted. When someone vomits repeatedly, has persistent diarrhea or sweats voluminously, there can be a serious loss of electrolytes, in addition to the water loss. Products like Gatorade have been formulated to restore both electrolytes and water in a rapid manner and that is why athletes drink it. The doctor who treated you may have given you tablets that contain all the appropriate salts necessary to restore a normal chemical equilibrium in the body. But without the lost water being replenished, the salts in the tablets would probably hurt the situation more than help it. The "rehydration solution" you mention is the key. It appears that you were replacing lost water and electrolytes in the same drink.After being pretty seasick you tend to be dehydrated and a way to help combat dehydration is to take a rehydration solution, sometimes in powder format or sometimes tablet. In fact the only effective treatment for dehydration is to replace lost fluids. I happened to be sharing my cabin with a doctor and she offered me some straight away but I already had my own with me. The Captain on the liveaboard also offered me some.
I am not a doctor myself but cannot see how taking rehydration tablets when dehydrated will make the dehydration worse.
Apologies as this is probably too much information but you can generally tell if you are sufficiently hydrated by the colour of your urine. After being pretty violently sick it was pretty obvious from the colour I was dehydrated, after taking the rehydration solution it became clear again and combined with the anti sickness injection administered by my doctor cabin buddy I started to feel a lot better again.
Please feel free to correct me if you think the above is completely wrong but I must admit I was surprised to see peoples comments on rehydration tablets.