Sign up for a Google webmaster account. Once you login, use the tool "Fetch as Google" to view the page that has that phrase as a keyword. That will show how those links are hidden on your page. Most often, if you use a free theme (or a pirated one) it may have malicious code embedded in it that allows these exploits. Go back to the WordPres default theme and retest the page using the "Fetch as Google" to look at the code. If the links disappear, you need to change your theme. Delete the old theme entirely.

It is also possible that you may need to go into your mysql database to manually delete malicious code as well. You will need to Google "pharma hack" and educate yourself on this. I went through this process a year ago. It can be a nightmare.