How much does Malarone cost in Nairobi?

Hi. Travelling to Kenya in 3 weeks time and I've just had a slight shock at the price of antimalarials in the UK. How much do they cost in Nairobi and where can we buy them there? My partner has a few pills left so we'll be ok for the beginning of our trip, but I'm keen to buy the rest over there if they are considerably cheaper. We are staying near a large Naivas suppermarket, I don't suppose they have a pharmacy there? We want a generic Malarone. Thanks for any tips xx