I used to get sinus infections ALL of the time. My dr gave me a prescription for Singulair since Claritin stopped working for me too. As long as I take Singulair every day and keep myself hydrated I haven't been getting as many sinus infections. And since I quit smoking 7 years ago, hardly ever at all. I have a friend who swears by rinsing her sinuses out with a saltwater solution but it is too gross for me to handle. www.achooallergy.com explains how it's done. She says she hasn't had a sinus infection since she started doing this.
For me if it lasts more than 10 days I head to the doctors, for medicine. Otherwise I take hot showers to loosen all the gunk up and blow it out. I also use the Breathe-rite nose strips with Vicks Vapo-rub in them when I sleep. My cousin's wife uses a Neti Pot and flushed her sinuses out. If they keep happening you need to find out why. Allergies can bring them on, or my case I had a deviated septum and had to have surgery to fix it.
There is a heat treatment inside the nostril, in allopathy, that is almost parmanent
I would use plain saline spray several times a day, and talk with you doctor about it.
Well, if it's an infection then the only way to cure an infection is with an antibiotic. Claritin is an allergy pill.