Can i take ritalin (methylphenidate) 10 mg one in the morning and one at night ( 7 pm ) ? would the night dose be dangerous or cause me problems ?

Ritalin (methylphenidate) at night: If the Ritalin (methylphenidate) dose you are referring to is not an extended release version, the evening dose should be out of your system in about 3-4 hours. It may reduce your ability to fall asleep tonight, but taking that dose is not dangerous. The extended release version would last about 8 hours, so I wouldn't recommend taking that one in the evening.

Hard to say: Ritalin (methylphenidate) varies in its effect on people. For some the increase in alertness can make sleep difficult if it is still in your system while some actually sleep better when they take it at bedtime. Every nervous system is somewhat unique and you will need to find how it effects you.At that dose level it will not hurt you to try it that way.

Response: Ritalin (methylphenidate) is a stimulant to help focus, concentration and keep you awake. If you take in early evening, you will not be able to sleep.

Modify time: I would auggest taking the 2nd doe at 3-4 pm. This prevens insomnia if that's a concern at night. Seems late for a second dose generally in my experience.