What was the culprit who fed Viagra to two horses in Macau getting up to? Lovely and Southern Hope, who between them won three races there last month, were disqualified after testing positive for the impotence drug. Their trainer was fined £20,000 and banned for five months. Sildenafil, the main derivative of Viagra, is a stimulant that could make horses run faster or react quicker. But perhaps the doser had another idea.