ProHeart 6, a drug that prevents dogs from getting a heartworm, has been approved by the Food and Drug Administration agency to make a limited return on the US market.

Four years ago, the drug was withdrawn after numerous pet owners and veterinarians reported adverse reactions in dogs that had been treated with ProHeart 6. Among these adverse reactions there have been cases of seizures, loss of appetite, vomiting, lethargy as well as difficulty walking and bleeding disorders.

Back in 2004, the company that produced the drug, Fort Dodge Animal Health, voluntarily withdrew the drug from the US market. After making some research of its own to determine the cause of these problems, the company found out that the adverse reactions were due to some residues of a solvent used to manufacture the drug.

The company has since revised its manufacturing process, and there have been significantly fewer reported cases of allergy on the markets where the drug had been still administrated.

ProHeart 6 will be released during a risk minimization and restricted distribution program, which means that there will be a restricted number of veterinarians that will be able to prescribe it. What is more, they will have to register for an online training program with Fort Dodge Animal Health, and will have to report to the company every case of allergic reactions to the product.

The drug is used for the prevention of heartworm disease, which is a potentially fatal condition for dogs. In order to benefit from the protection that the drug offers, dogs need to be given an injection every six months.