WASHINGTON — As consumers face rapidly rising drug costs, states across the country are moving to block “gag clauses” that prohibit pharmacists from telling customers that they could save money by paying cash for prescription drugs rather than using their health insurance.

Many pharmacists have expressed frustration about such provisions in their contracts with the powerful companies that manage drug benefits for insurers and employers. The clauses force the pharmacists to remain silent as, for example, a consumer pays $125 under her insurance plan for an influenza drug that would have cost $100 if purchased with cash.

Much of the difference often goes to the drug benefit managers.

Federal and state officials say they share the pharmacists’ concerns, and they have started taking action. At least five states have adopted laws to make sure pharmacists can inform patients about less costly ways to obtain their medicines, and at least a dozen others are considering legislation to prohibit gag clauses, according to the National Conference of State Legislatures.

Senator Susan Collins, Republican of Maine, said that after meeting recently with a group of pharmacists in her state, she was “outraged” to learn about the gag orders.