Merck & Co., mired in multibillion-litigation over its withdrawn painkiller Vioxx, has eliminated another legal headache, resolving several tax disputes with the Internal Revenue Service by agreeing to a $2.3 billion settlement.

In announcing the agreement Wednesday, the Whitehouse Station, N.J.-based company said the settlement resolves all outstanding tax disputes with the IRS, covering the years 1993 through 2006. Merck had faced potential taxes, interest and penalties totaling as much as $3.8 billion, but the agreement apparently reduced that amount.