There’s another new option available to treat arthritis: biosimilar drugs. They are highly similar to the original biologic drugs that they were designed to mimic.

Why would you get these drugs instead of a biologic or switch to a biosimilar? The main reason is price. They can be cheaper than the biologic they were designed to mimic.

At this time, all biosimilars have the reference biologic drug’s name with a four-letter suffix after it to let doctors and pharmacists know which particular biosimilar it is. Biosimilars are designed to be as effective as the original biologic and to have the same side effects.

Biosimilars will be taken in the same way as their reference drug, and have the same possible side effects, contraindications, and monitoring tests. All biosimilars have to meet the same standards of safety and efficacy as any other prescription drug approved by the FDA. But because they cost less to develop and test, they may not be quite as expensive as other biologics. However, biosimilars are not identical to the original drug — they’re just highly similar.

Each state has different laws about how biosimilars may be substituted for their reference biologic when a prescription comes to the pharmacy. If you have any concerns, talk to your doctor about your state’s rules. More than 35 states have passed laws so far that require pharmacies, including mail-order specialty pharmacies, to notify doctors if they plan to substitute a biosimilar for the reference biologic. Physician associations, pharmacists’ groups, the FDA, pharmaceutical companies, and others are still debating these issues.

In the future, there are expected to be biosimilars that have a higher level of similarity their reference biologics. These drugs will have to meet this higher standard for the FDA to designate them as interchangeable. There are no interchangeable drugs in development yet, and the FDA has not even established the criteria for designating a drug as “interchangeable.” When and if a drug is given the interchangeable tag in the future, pharmacists may be able to substitute that drug for the original reference biologic when they fill a prescription from a rheumatologist.