There are no specific medicines used to treat mono. Over-the-counter medicines may be used to help treat the symptoms of mono.n severe cases, corticosteroids may be used to reduce swelling of the throat, tonsils, or spleen. Taking antibiotics such as amoxicillin or ampicillin may cause a rash in many people who have mono. A rash caused by antibiotics can often be a first sign that the person has mono.