an infusion catheter for delivering drugs or other agents to selected sites in an organism , such as a human . in an alternate embodiment , a catheter system is disclosed having an infusion catheter and a pump that may be implanted or disposed outside the organism . in either embodiment , the free end of the catheter bears a rounded tip that has at least one elution hole for discharging an agent or drug to a selected site . the catheter has a tubular inner liner that is integral with the tip . the inner liner and tip are formed from a drug compatible polymeric material that is relatively nonporous and unreactive with the agent to be infused . a biocompatible flexible elastomeric tubular jacket surrounds the inner liner and a portion of the tip excluding that portion containing the elution hole or holes . since the agent flowing in the catheter is isolated from the jacket while flowing through the catheter , and since the inner liner is relatively nonporous and unreactive with the agent to be used , the agent is prevented from diffusing out of the catheter , adsorbing to the surface of the biocompatible jacket , reacting adversely with the jacket material or becoming exposed to substances diffusing through the jacket .