Prescriptions for Asthma Inhalers Surged 42% After NorCal Fires

Jeroen van Meijgaard
Jeroen van Meijgaard, PhD, is a health economist and conducts data analysis and outcomes research for GoodRx.
Posted on

Prescriptions for asthma inhalers surged by over 40% in the San Francisco Bay Area in the month of last October’s Northern California fires in Napa and Sonoma counties, according to a GoodRx analysis of pharmacy data.

In Marin County, inhaler prescriptions climbed by 78% in Oct. 2017, with prescriptions in Napa rising by 67% and San Francisco, Sonoma, and Contra Costa climbing by about 50% in the month during the fires. Even in Santa Clara and Santa Cruz counties, which are about 100 miles from the major burn areas, there were around 20% more inhalers prescribed than the same period a year previous.

The analysis is based on a large sample of prescriptions filled at pharmacies in the region, and compared the number of fills of inhalers during October 2017 – the month of the Napa and Sonoma fires – to the previous October. The data includes 26 asthma medications, including Proair, Ventolin, Advair, Symbicort, and Flovent. The data comes from several sources, including pharmacies and insurers. The Napa and Sonoma fires first broke out on the evening of October 8, and were fully contained by October 31.


County Year/Year Increase
overall average 42%
Marin 78%
Napa 67%
Solano 53%
Contra Costa 52%
Sonoma 50%
San Francisco 49%
Alameda 41%
San Mateo 35%
Santa Clara 23%
Santa Cruz 18%


Asthma inhaler prescriptions tracked prevailing wind patterns

The prescription surge tracks with the wind and smoke pattern in the days during and after the blazes. Initially, smoke from the fires was being pushed west over Marin county; later, as the winds changed, smoke drifted south and south-west over densely populated areas, including the cities of Oakland and San Francisco, and as far south as Santa Cruz county.

For some the smoke is just a nuisance, but for individuals who suffer from respiratory conditions, such as asthma or chronic obstructive pulmonary disease, smoke in the air can create serious health problems leading to missing school or work, or even requiring a visit to the ER or hospital.

Inhalers are generally prescribed to provide relief from environmental pollutants causing breathing difficulties, and short-acting bronchodilators can provide quick relief when the airways are constricted.

Inhaler prescriptions in Ventura county also climbed

Only two months later, on December 4, one of the largest fires ever in California broke out in southern California’s Ventura county, about 70 miles northwest of Los Angeles. During the worst of this fire the prevailing winds pushed the smoke west and southwest, limiting the impact on Los Angeles. However, Ventura county was significantly impacted by the smoke.

Similarly to what happened in the Bay area in October, there was a sharp increase of asthma inhaler fills during the month of the fire in Ventura county. This increase extended into January after the fire had been mostly contained, suggesting that people may have refilled prescriptions sooner than they would normally because of increased use during the worst of the fire.

When wildfires occur far from population centers, the impact on asthma sufferers may not be readily apparent. However, recent fires in California occurred close to major cities. At the time, news reports focused mostly on the immediate damage from the wildfires, but as is clear from the prescription fill data, the fires had a significant impact on the health and well-being of people in a large area downwind from the fires.

People with asthma and others with compromised respiratory function should be aware of the importance of managing their health condition, and should use the appropriate medications in consultation with their doctor to prevent worse outcomes, including hospitalization, during times of poor air quality.

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