Jan 29 (Reuters) - Health insurer Cigna's ( CI ) unit

Evernorth Health said on Wednesday it will make changes to help

lower out-of-pocket cost of prescription drugs for patients at

its pharmacy stores.

The changes will protect patients from paying a high list

price for their medication by giving them access to lower prices

negotiated by Cigna's ( CI ) pharmacy benefit manager, Express Scripts.

Insurers that own pharmacy benefit managers (PBM) have come

under pressure due to their influence over drug pricing.

CVS Health's ( CVS ) Caremark, Cigna's ( CI ) Express Scripts and

UnitedHealth Group's Optum together control the majority

of the U.S. pharmacy benefit market, while their parent

companies operate health insurance and pharmacy businesses.

The PBMs negotiate drug costs with pharmacies and drug

manufacturers and help build drug coverage lists for health

plans, mostly on behalf of employers and the government.

The pharmacy benefit managers directly reimburse pharmacies

for prescription drugs included under their agreed terms.