Arthritis - how good is Fosamax?

My husband has recently been diagnosed with arthritis - rheumatoid and osteoporosis. This morning he started taking Fosamax and within 30 minutes started getting a severe headache and a sour stomach. Is this a side effect? He doesn't need more problems just to feel better for another. None of us do. I pray the Lord will help him cope and for us to know what to do.