Pharmacist Role with Biosimilars: Counseling and Substitution

When a patient walks into the pharmacy with a prescription for a biologic drug like Neulasta or Humira, they’re not just getting medicine-they’re stepping into a complex system of science, regulation, and trust. And the pharmacist? They’re the one who holds it all together.

What Makes Biosimilars Different from Generics?

People often think biosimilars are just like generic pills. They’re not. A generic version of a drug like lisinopril is chemically identical to the brand name. It’s made in a lab with exact formulas. Biosimilars? They come from living cells-yeast, bacteria, or mammalian cells. Even small changes in the process can lead to tiny structural differences. That’s why the FDA doesn’t call them "identical." They call them "highly similar." And crucially, they must show no clinically meaningful difference in safety, purity, or potency compared to the original biologic.

This isn’t semantics. It’s science. And it changes everything about how pharmacists handle them. You can’t just swap a biosimilar like you would a generic. There are rules. There’s paperwork. And there’s patient fear to overcome.

Interchangeable vs. Non-Interchangeable: The Key Distinction

Not all biosimilars are created equal. The FDA has a special designation: interchangeable. This means a pharmacist can substitute it for the original biologic without asking the doctor-just like a generic. But as of late 2023, only a handful of biosimilars have earned this status. Most still require the prescriber to explicitly allow substitution.

Why does this matter? Because if a biosimilar isn’t interchangeable, the pharmacist can’t switch it without calling the doctor. That creates delays. It adds work. And it often means the patient ends up with the more expensive brand-name drug-even if the biosimilar is cheaper and just as safe.

That’s where pharmacists step in. They don’t just fill prescriptions. They push for change. They educate. They advocate.

Why Pharmacists Are Leading the Charge

Doctors are busy. Nurses are stretched thin. But pharmacists? They’re the ones holding the medication records, reviewing the formulary, and talking to patients daily. A 2022 study in the Journal of Managed Care & Specialty Pharmacy found that 87.3% of pharmacists recommended biosimilars to patients-compared to just 62.1% of physicians. Why? Because pharmacists get the training. They attend CEUs on biosimilars. They read the data.

At the US Oncology Network, when they shifted substitution decisions from doctors to pharmacists, adoption of the pegfilgrastim biosimilar jumped overnight. Before, doctors had to approve every switch. After? Pharmacists reviewed the chart, confirmed the patient was stable, and swapped it automatically. Daily interruptions dropped. Costs fell. Patients stayed on therapy.

It wasn’t magic. It was structure. They trained every provider. They got written consent. They built a workflow. And they didn’t just rely on policy-they used data.

How to Counsel Patients Without Scaring Them

Patients hear "biosimilar" and think "cheap version." They worry it won’t work. Or worse-they think it’s unsafe.

Here’s what works: start with facts, not jargon.

• "This medicine is approved by the FDA as highly similar to the original. It works the same way in your body."
• "Thousands of people have used it. The data shows no difference in how well it works or how safe it is."
• "The only real difference? It costs less-so your insurance pays less, and you pay less too."

One pharmacist in Sydney told me about a patient on a biologic for rheumatoid arthritis who refused to switch. "I’ve been on this for five years. Why change?" she asked. The pharmacist didn’t argue. He showed her the FDA’s 9 Things to Know About Biosimilars. He pulled up the clinical trial results. Then he said, "If this wasn’t safe, they wouldn’t let us give it to you. But they do. Because it’s proven."

She switched. And stayed on it.

But it’s not just about trust. It’s about appearance. If the pill changes color, shape, or size-even if it’s the same drug-patients are 21% more likely to stop taking it. That’s why pharmacists must explain packaging changes before the patient even gets home. A quick note in the bag. A verbal heads-up. It makes all the difference.

The Legal Patchwork: State Laws and Substitution Rules

In Australia, pharmacists have broad authority to substitute biosimilars under the Therapeutic Goods Administration guidelines, as long as the product is approved and the patient is informed. But in the U.S.? It’s a mess.

As of October 2023, 48 states have laws about biosimilar substitution. But the rules vary wildly. Some require the prescriber to opt out. Others require the pharmacist to notify the doctor within 24 hours. A few demand that the patient sign a consent form. And only a handful allow automatic substitution for interchangeable biosimilars without any extra steps.

That’s why pharmacists need to know their state’s law-cold. One wrong move, and you’re risking liability. Or worse-you’re denying a patient a cheaper, equally effective option.

And then there’s traceability. Every biosimilar must be tracked by batch number. Why? Because if something goes wrong-say, an unexpected immune reaction-you need to know exactly which version the patient got. That’s not just good practice. It’s required.

Why This Matters for Costs and Access

Biologics make up only 2% of all prescriptions in the U.S.-but they account for nearly half of all drug spending. That’s not sustainable. A single course of Humira can cost over $20,000 a year. The biosimilar version? Around $6,000. That’s a 70% drop.

When pharmacists actively promote biosimilars, savings add up fast. At US Oncology, switching just one drug-pegfilgrastim-to its biosimilar saved the system over $1 million in the first year. Multiply that across dozens of biologics, and you’re talking billions.

But cost isn’t the only win. It’s access. Many patients can’t afford the brand-name drug. Without biosimilars, they skip doses. Or skip treatment entirely. Pharmacists who push for substitution aren’t just saving money-they’re saving lives.

What Pharmacists Need to Succeed

It’s not enough to know the science. You need systems.

• Get trained. Take CEUs on biosimilars. The FDA, ASHP, and ISOP offer free resources.
• Know your state’s substitution law. Bookmark it. Review it quarterly.
• Build a checklist: Is the biosimilar interchangeable? Is the prescriber okay with substitution? Has the patient been counseled? Is the batch number recorded?
• Partner with your pharmacy benefit manager. Ask them to simplify prior auth forms for biosimilars.
• Document everything. In the EHR. On the label. In the patient’s file.

And don’t be afraid to push back. If a doctor refuses to allow substitution without a good reason, ask why. Show them the data. Share the patient stories. Sometimes, they just haven’t heard the full picture.

The Future Is in Your Hands

Biosimilars aren’t the future. They’re here. And they’re working. But they won’t reach their full potential unless pharmacists take the lead.

You’re not just dispensing pills. You’re changing how care is delivered. You’re reducing financial toxicity. You’re building trust where fear once lived. And you’re doing it with science, not sales pitches.

The next time a patient asks, "Is this the same?"-you don’t need to guess. You know. And you’re ready to explain it.

What Comes Next?

Look ahead. The FDA is considering eliminating the separate "interchangeable" designation entirely. That could simplify substitution dramatically. States are updating laws to match. More biosimilars are coming-oncology, autoimmune, diabetes. The market is growing fast.

But the biggest barrier isn’t science. It’s perception. And that’s where pharmacists win. You’re not just filling scripts. You’re rewriting the narrative.

So next time someone says, "Biosimilars aren’t the same," you don’t argue. You say: "They’re not identical. But they’re proven. And they’re saving people money-and lives."