It will ruin the fast to take any kind of medicines.

Blueduck

The best thing you can do is drink water, I think. I am on day 4 and had a pretty bad headache on day 1 - I drank more water and sat down - it did not go away completely until I woke up the next day, but it never became so intense I had to take an aspirin. Good luck. Stay with it if you can; the results are incredible.