Illinois lawmakers looking for ways to cut expenses in the state’s Medicaid program may consider the big-ticket cost of prescription drugs as a tempting target. Prescriptions cost the Illinois Medicaid program more than $1 billion a year. Medicaid covers drugs for a wide variety of illnesses, from asthma to schizophrenia, for the poor and disabled. Legislators are looking at other states for ideas. Tennessee, for example, limits adults to five prescriptions each month.