Depends on the dosage. I would not recommend exceeding the guidelines on the bottle without a doctor's suggestion. I'm not a doctor. My advice does not constitute advice from a medical professional.
That being said, I take 800mg at a time 5x a day when I need it with no ill effects. I've been prescribed 3-4 times this amount before and it was fine. This is my experience, yours may be different.
Anastas Dimitar Martin