The Maryland State Racing Commission voted today to liberalize the rules regarding the use of the diuretic Lasix. The unanimous decision came as a result of a ruling last week by Circuit Court Judge Robert I. Hammerman, who found the current regulations on the drug were "arbitrary, capricious and unreasonable."

The new rules, which Commissioner E. William Furey described as "interim," will allow horses who have been determined--by the use of an endoscope--to bleed internally after exertion to be eligible for treatment with Lasix.

Previously, the only way a race horse in Maryland could qualify for the treatment was to have been seen bleeding from the nostrils by a state veterinarian.

The new rules will also allow for a state veterinarian to deputize private practitioners in determining bleeders. It is estimated that, with the liberalized rules, some 50 percent of the horses in training will qualify. Under the previous procedure, only 5 to 7 percent did.

Commenting on the decision, Commissioner Kenneth Proctor, a former judge, said, "We have to abide by Judge Hammerman's decision, since this commission has no appeal of that decision. This commission will have a clear, permanent rule in place by Oct. 24 of this year."

The reason for the delay is that there will be a national meeting of state racing commissions in August and the Maryland group could be guided by any findings on Lasix.

"We could come in with a rule that would bar all medication or open up the rules for everybody to use Lasix and/or Bute (Butazolidin) at will," Bob Banning, commission chairman, said. "We'll hear all the testimony all over again and be ready by October."

Katy Voss, speaking for the horsemen, said, "We won this round, but that (interim rule) and Proctor's suggestion that the commission's (permanent rule) will be more stringent is not too heartening. However, (owner-breeder Robert) Manfuso, who brought this petition to the commission for us, has made his point: the Maryland rules in determining bleeders was unsatisfactory."

Judge Hammerman, in his opinion, said, "We'll fight to keep the endoscopic feature in any future law."