My daughter (20 years old) is feeling like she had a high dose of caffeine as well as experiencing significant hand tremors. She took a dose of the medication (5mg) last night before going to bed (10:30 pm, and she awoke at 10:30 am with these symptoms. She is also on methotrexate and oxaprozin for rheumatoid arthritis, but was just put on flexoril (generic form) for tortacolis (tightening of the neck muscle).