Patanol is an antihistamine and mast cell stabilizer whose effect is that of relieving the effects of allergies on the eyes. It is not recommended to make use of this medicine in case of irritations caused by contact lenses. It is to be applied directly on the eyes, rather than taken orally or injected. The usual dose is 1 drop in each affected eye 2 times a day, with 6 to 8 hours between doses.