The American Horse Shows Association’s Drugs and Medications program has begun allowing the use of Lasix (furosemide) to expedite the collection of urine in show horses. Lasix is a safe and effective diuretic is used in small doses, according to John Lengel, DVM, Administrator of AHSA’s Drugs and Medications Program.

The testing veterinarian needs the written permission of the owner or trainer to administer up to 100 milligrams (2ccs) of Lasix intravenously to hasten the collection of a urine sample. This dosage usually produces a urine sample within 15 minutes. Giving permission to use the drug is voluntary and only the owner or trainer is authorized to give permission.

There is no set time limit before the administration of Lasix and it may be administered under the following conditions:

1. Any alternate veterinarian must be compensated by the trainer or owner;
   
2. The dose of Lasix must be prepared by the AHSA testing veterinarian using his or her syringe and Lasix;
   
3. The injection must be performed in the presence of and at the convenience of the AHSA testing veterinarian; and
   
4. The used syringe must be returned to the custody of the AHSA testing veterinarian.

The use of Lasix in the 1970s was common, but its use was discontinued due to the controversy over the possible dilution and/or masking effects of the drug. Now, with the development of improved testing technology, this is no long a problem when only a small dose is used