In the year-ago quarter, Pfizer took charges totaling $1.66 billion, for litigation, acquisition and other costs.Overall, revenue was $13.5 billion, down 9 percent from $14.89 billion a year earlier and below analysts' expectations of $13.99 billion.Besides the loss in revenue from some off-patent drugs, Pfizer had declines in revenue of some big sellers protected by patents, including erectile-dy