Is prelox safe for childs as well?

Highly doubt it. Prelox is a combination product designed to enhance blood flow and sexual performance in men. There is really no good reason why a child would take it, except by accidental ingestion. It is completely untested, and dosing is not available. Medicines like this are not 100% safe in adults and are certainly not safe in children.
Doubtful. There are only a few well-designed studies on prelox in adult males, and i could find no studies on it with children (given what it is marketed for, that's understandable!). I would strongly advise calling the poison control center (1-800-222-1222) if you think your child has taken some;keep it in a cabinet with a childproof lock along with any other medicines.