I had headaches when I first started taking Plaquenil 10 yrs ago. My Dr had me take one half the dose in the morning and the other before bed for about a month. This helped a lot so that now I take it all at night. He recently took me off but put me back on when they found that it reduced the likelihood of developing diabetes in RA patients. Also be sure to see your eye dr as this could effect your peripheral eyesight.