New Prescriptions (NRx)

Key facts

Formula

Total prescriptions (TRx) minus refills

Counted when

The original fill of a prescription is dispensed

Includes

Fresh prescriptions for patients already taking the product

Excludes

Refills of an existing prescription

What are new prescriptions?

A new prescription is counted when a pharmacy dispenses the first fill of a prescription. Later refills of that same prescription count toward total prescriptions (TRx) but not toward NRx.

The word new describes the prescription, not the patient. When a patient's refills run out and the prescriber writes a fresh prescription for the same drug, the next fill is an NRx even if the patient has taken the product for years.

Drug scheduling also affects NRx. Federal rules prohibit refills of Schedule II controlled substances, so every dispensed prescription for those drugs is an original fill.

How NRx is counted

Vendors agree on the core rule but handle edge cases differently:

Check the definition behind any NRx figure before comparing sources or time periods.

• Pharmacy transfers: some sources count a transferred prescription as new at the receiving pharmacy, while others treat it as continuing.
• Days supply: some sources normalize 90-day fills to 30-day equivalents, which raises counts relative to raw prescriptions.
• Channel coverage: inclusion of retail, mail order and specialty pharmacies varies.
• Patient-level variants: some vendors also report new-to-patient counts, which are closer to new-to-brand prescriptions (NBRx) than to NRx.

Why NRx matters

NRx reacts faster than TRx to changes in prescriber behavior because it is not padded by refills from long-standing patients. Brand teams watch NRx after a launch, a new indication, a label change or a competitor entry, and field teams use prescriber-level NRx to see where prescribing is changing.

NRx share within a drug class usually moves ahead of TRx share, so it serves as a leading indicator of where total volume is heading.

NRx vs NBRx

Because NRx mixes truly new patients with renewals for existing ones, it overstates new patient demand. New-to-brand prescriptions (NBRx) use patient-level longitudinal data to isolate patients who have not recently taken the product, which makes NBRx a cleaner measure of patient starts. NRx remains useful where patient-level data is not available, since it can be built from pharmacy-level dispensing records alone.