Talk to Neuro Physician on Epileptic

My sister 22 years is taking trioptal 300 mg.one at night and one in morning . Today she couldn't remember if she had taken the night dose so she took one and now v r worried if she had taken double dose. She says she doesn't remember but is in doubt whether she took the night tablet or not . She had two fits last year on November after which v took her to dr nasrullah.and up till now after medicine she has been fit free