Most definitely, and you need to take them for a few weeks before you travel, whilst on holiday, and for a few weeks on your return. There are trips in the evening, like going to the Temple of Philae, where you will be bitten mercilessly regardless of how much repellent you lather yourself with. Better safe than sorry!
One thing i will say is that the pills gave me rotten heartburn each afternoon so be prepared with some strong antacids!
To follow on from KARL's post, be very careful of what you eat! Although ice cubes maybe from bottle water, fruit and uncooked veg will most certainly not have been, even in top hotels, avoid it like the plague! And avoid ice when off your cruise or out of your hotel too. Use bottle water to brush your teeth and keep your mouth closed whilst in the shower. I did the above and managed to stay gippy tummy free, unlike my friends.
You'll have a fantastic time so long as you use a bit of common sense! I wish I was going back :o)