New York, April 12 (Reuters): Abbott Laboratories Inc said on Tuesday its quarterly net earnings rose 1.8 per cent as higher sales of prescription drugs helped offset several special charges.

The company, which also makes medical devices and diagnostics, earned $837.9 million, or 53 cents a share, in the first quarter, up from $822.9 million, or 52 cents a share, a year-ago. The 2004 quarter included the sale of lower-margin hospital products that were spun off into Hospira Inc.

Earnings from continuing operations, excluding special charges, rose 9.4 per cent to 58 cents per share ? matching the average estimate of analysts.

Sales jumped 16 per cent to $5.38 billion, but would have risen only about 13.5 per cent if not for the weak dollar, which raises the value of products sold in overseas markets when translated into dollars.

Sales of prescription drugs rose 20 per cent, helped by strong demand for arthritis drugs Humira and Mobic, HIV treatment Kaletra and antibiotic Biaxin.