Healthcare and pharma advertisers’ US online ad spend is expected to see double-digit growth over the next few years, rising from $1.03 billion in 2010 to $1.86 billion in 2015, eMarketer predicts.

The industry accounted for 4.0% of the $25.8 billion spent on overall US online advertising last year, according to new estimates from eMarketer, and its share is set to climb to 4.2% by 2015. For this year, the intelligence firm forecasted, the industry will up web spend 13% to $1.17 billion.

On a percentage growth basis, that puts the health and pharma vertical roughly on par with the retail and automotive industries, pegged to see 11% and 14% growth this year, respectively, and behind consumer packaged goods, which is forecast to grow internet spend 29% to $2.7 billion. Looking ahead, retailers will soon account for more than one in every five online ad dollars, noted eMarketer.

These other industries are increasing use of online video ads as an alternative to pricy TV commercials, according to the intelligence firm. Drug manufacturers and marketers, seeing brand revenues shrink from expiries, are also investing more heavily in web promotion, but many are awaiting guidelines from regulators.

“Healthcare and pharma spending will continue to move online, but spending will likely be affected by the loss of patent protection for several blockbuster drugs and forthcoming guidelines from the US Food & Drug Administration, which many in the industry hope will provide clearer direction for how pharmaceutical products can be marketed online,” eMarketer said in a statement.

Doctors, hospitals and other entities that deliver health services, such as HMOs, are also expected to contribute to the upward trend.

More mature online advertising verticals—including telecom, financial services and travel—are expected to grow online spend but lose share through 2015 because they are already heavily invested online, eMarketer said.