Warren, among the frontrunners in the 2020 presidential race, released a survey Monday, which looked at 190 chains and 196 independent pharmacies across all 50 states. The results found that 83% of pharmacies surveyed did not have Lispro, Eli Lilly's rebranded cheaper insulin, in stock or available to customers. In some cases, the pharmacists did not inform customers that a cheaper version was available.
"This report shows that pharmaceutical giant Eli Lilly has not lived up to its promise to provide a lower-priced insulin to patients who need it," Warren said in a statement.
Ricks shot back on "Mad Money" on Tuesday, telling CNBC's Jim Cramer that the company's half-priced insulin is "a pretty big difference" to consumers and is "widely" available.
That's "nonsense," he added. Warren's report shows "what's broken in the rest of the pharmaceutical system."
Ricks, who said he had not seen the details of Warren's report, instead pointed his finger at pharmacy benefit managers, which negotiate drug benefits with manufacturers for insurance plans and employers.
Eli Lilly announced back in March that it would sell a half-price version of Humalog, fending off criticism about rising drug prices in the United States. The rebranded product, called Lispro, would be $137.35 per vial, the company said. High prescription drug costs have become a rare bipartisan issue, with both Democrats and Republicans in Congress demanding changes.
Ricks appeared on CNBC after the drugmaker announced earlier Tuesday it sees a higher-than-expected profit for 2020, citing growing demand for its medicines.