What other medications do you take? Some have been known to cause this... When I used to take pharmaceuticals, I found out at a very young age most anything ending in ine caused me problems...
For example, here are some of the side effcts of tetracyline;
severe headache
blurred vision
skin rash
hives
difficulty breathing or swallowing
yellowing of the skin or eyes
itching
dark-colored urine
light-colored bowel movements
loss of appetite
upset stomach
vomiting
stomach pain
extreme tiredness or weakness
confusion
joint stiffness or swelling
unusual bleeding or bruising
decreased urination
pain or discomfort in the mouth
throat sores
fever or chills