WASHINGTON, D.C. — Johnson & Johnson will begin marketing four of its medications on the Trump administration's TrumpRx discounted drug website on Friday. The addition more than doubles the number of drugs featured on the site since it launched in February.

The four medications include metformin, which is commonly prescribed to treat Type 2 diabetes, and metformin extended relief. Also among the offerings are Invokana, a diabetes medication, and Xarelto, a blood thinner.

Johnson & Johnson announced in January that it had entered into a voluntary agreement with the Trump administration to lower costs for Americans by providing Medicaid access to affordable prescriptions and to market its drugs on TrumpRx. In exchange, the company received an exemption from the president's tariff agenda.

The TrumpRx site first launched in February. With the addition of the four Johnson & Johnson drugs, the site now features more than twice the number of medications it carried at launch.

Prescription drug prices on the TrumpRx site are available only to patients who are uninsured or whose insurance does not cover the drug. Those patients are required to pay the full list price out of pocket. Patients with insurance coverage generally pay lower prices for prescription drugs.

The TrumpRx website is operated by the White House as a discounted pharmaceutical platform. The voluntary agreement Johnson & Johnson entered in January is one of several arrangements the Trump administration has pursued with drug manufacturers to make medications available through the site.