IV Tildren for Navicular Syndrome The efficacy of administering the injectable bisphosphonate medication for horses (Tildren) in two different ways was evaluated for the treatment of navicular syndrome. Twelve horses diagnosed with bilateral navicular syndrome were randomly assigned to receive Tildren either systemically by intravenous injection or by using regional limb perfusion, where the drug is “back-flushed” directly into the blood vessels of the lower limb so that it is delivered to the lower limb and hoof in a more direct, concentrated manner.