The side effects of theophylline tablets, which are a combination of aminophylline and diphenhydramine, are mainly used to treat dizziness, motion sickness and seasickness. It has side effects such as drowsiness, sleepiness, lack of concentration, fatigue, gastrointestinal discomfort, slow reactions, and rare side effects such as hallucinations and loss of vision in a very small number of patients. For patients who suffer from motion sickness or seasickness, it can be taken orally when the symptoms of motion sickness are obvious or before riding in a car. Patients who are prone to motion sickness can go to the hospital to have their vestibular function tested to see if there is any vestibular sensitivity.