Last reviewed 2026-04-23 · How we verify

HFA-134a

HFA-134a is a hydrofluoroalkane propellant used in pressurized metered-dose inhalers (pMDIs) to deliver aerosolized medications to the lungs.

HFA-134a is a hydrofluoroalkane propellant used in pressurized metered-dose inhalers (pMDIs) to deliver aerosolized medications to the lungs. Used for Propellant for pressurized metered-dose inhalers delivering bronchodilators, corticosteroids, and other inhaled medications.

At a glance

Mechanism of action

HFA-134a (hydrofluoroalkane-134a, also known as norflurane) is a non-ozone-depleting propellant that replaced chlorofluorocarbons (CFCs) in inhaled drug formulations. It functions as a liquefied gas propellant that vaporizes upon release from the inhaler canister, creating the aerosol cloud that carries the active pharmaceutical ingredient into the respiratory tract.

Approved indications

• Propellant for pressurized metered-dose inhalers delivering bronchodilators, corticosteroids, and other inhaled medications

Common side effects

No common side effects on file.

Key clinical trials

• A Study to Assess and Compare Safety and Tolerability of 3 Months Treatment With Salbutamol Administered Via MDI Containing Propellant HFA-152a or HFA-134a in Participants ≥ 18 Years of Age With Asthma (PHASE3)
• Study to Assess Effect of Next-Generation Propellant MDI on Mucociliary Clearance Vs. HFA Propellant MDI in Healthy Participants (PHASE3)
• Therapeutic Equivalence of CHF5993 pMDI 100/6/12.5 µg HFA-152a in Subjects With Mild to Moderate Asthma (PHASE2)
• A Study to Compare the Pharmacokinetics (PK) of Salbutamol Administered Via Metered Dose Inhalers (MDI) Containing Propellants HFA-152A (Test) or HFA-134A (Reference) in Healthy Participants Aged 18 to 55 Inclusive (PHASE1)
• Comparison Between CHF5993 pMDI 200/6/12.5 µg HFA-152a VS CHF5993 pMDI 200/6/12.5 µg HFA-134a in Subjects With Asthma (TRECOS). (PHASE3)
• A Study to Compare the Relative Potency of Salbutamol Administered Via Metered Dose Inhalers (MDI) Containing Propellants HFA-152a to HFA-134a in Mild Asthmatics Aged 18 to 65 Inclusive (PHASE1)
• Advair HFA in Healthy and HAPE Predisposed Subjects (PHASE1, PHASE2)
• Functional Studies of Novel Genes Mutated in Primary Ciliary Dyskinesia II: Genotype to Phenotype (EARLY_PHASE1)

Primary sources

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