From today (August 15), most pharmaceutical company pages on Facebook are due to be open to comments for the first time, something which could strain the industry's difficult relationship with social media.

Many pharmaceutical companies only agreed to set up on Facebook in return for the ability to moderate and block comments on their pages, a privilege which was not accorded companies in other industries. The social media platform says it will however still allow comment disabling on some branded pages that refer to a specific drug.

Some drugmakers - including AstraZeneca and Johnson & Johnson - say they have decided to remove pages as a consequence of the policy change, according to a Washington Post article.

Pharma has always been wary of social media because of stringent rules governing the information it can impart to consumers, and has been much slower than other sectors in embracing Facebook and other social media platforms.

Drugmakers say they are concerned that commenters may reference side effects or proffer medical advice, or mention brands without 'fair balance', although critics of the stance argue their reluctance stems more from a lack of understanding about social media and fears about loss of control over brand image.

As of this morning (UK time), some company pages were still blocked from comments, while others are already allowing them.  For example, Pfizer's page appears with a lengthy explanation of the reasons why it may have to delete comments from its wall, but the comment functions are still not active. Pages for GlaxoSmithKline, AstraZeneca and Novartis were also comment-free this morning.

The industry has also said it lacks clear guidance from regulatory authorities on what it can and cannot communicate via social media. The US FDA has not yet released its own guidelines although it has suggested they may be completed before the end of this year.

For its part, Facebook now maintains that as a social media platform it is interactive by definition, and restricting comments undermines the entire purpose of the platform.

The message is that comment-free pages are essentially advertising, not social interaction, and the change in policy is necessary to encourage dialogue between drugmakers and their customers.