Tufts School of Medicine researchers say switches can reduce choices and raise prices for managed-care clients. They interviewed 12 top managed-care organizations and found "a strong tendency" to remove the switched drugs from their formularies -- a list of approved drugs -- and to raise co-payments on similar prescription medications.
"Increasing the co-payments of prescription drugs in the same class gives patients further financial incentive to take the over-the-counter drug," said the Tufts study in the British Medical Journal.
Researchers found that each managed-care firm removed loratadine from its formularies when the drug went OTC and raised co-payments for similar prescription antihistamines. Loratadine is the generic name for Schering-Plough's (SGP) Claritin. The researchers said one-third of the HMOs are removing all other similar antihistamines from their formularies.
The managed-care firms acted similarly with omeprazole, the generic name for AstraZeneca's (AZN - Get Report) Prilosec, which belongs to the proton pump inhibitor class. Eight removed omeprazole from their formularies, and seven raised the co-payments for prescription proton pump inhibitors.