Can you put it on the scales, please? changing from effexor to pristiq Zealand plunged 15 percent to close at 66 kroner at 5:30p.m. in Copenhagen. The stock declined as much as 23 percent,the biggest intraday drop since the companyâs Nov. 24, 2010,initial share sale. Sanofi sank 2.6 percent to close at 72.32euros.