I guess you are referring to Propranolol 10 mg. If so, this is used treat high blood pressure, treat pain in the chest caused by blockages in the arteries leading to the heart. You may have side effects such as allergies, hallucination, cramps etc. While Modalert 100 mg is a medication is used to treat narcolepsy, which is uncontrollable daytime sleepiness. Irrespective of the above, it is not advisable to take medication without doctor's advise. If your already had consulted a doctor and the above were prescribed by the doctor, you can talk to the same doctor (as he/she will surely know better). There are probabilities of changing medication. If you have taken your own decision to take these medicines because of some non-medical person suggested or you got some info on Internet etc. then you are inviting unwanted trouble. Consult your doctor immediately and take professional advise