Medication infusion device with dose recharge restriction

Abstract

A subcutaneously implantable medication infusion device includes a variable capacity reservoir for receiving and storing fluid medication for delivery to a catheter which directs the medication to a specific infusion location in the body. A control assembly is interposed between the reservoir and the catheter to facilitate and control the transfer of the medication from the reservoir to the catheter in a safe and efficient manner. The control assembly includes a self-recharging pump and a normally closed valve, both of which are manually actuable by percutaneous pressure when subcutaneously implanted, and defines a portion of a fluid flow conduit between the reservoir and the catheter. The control assembly is constructed to permit the infusion of a measured bolus of medication on demand through manual percutaneous manipulation of the control assembly. A restrictor is provided the control assembly to limit the rate the pump is recharged with medication, to restrict the total amount of medication which can be pumped into the catheter over a given period of time. In one preferred form, the pump recharge restriction is created by providing at least one capillary-like fluid pathway through which the recharge fluid must pass before entering the pump. In another preferred form of the invention, the recharge flow rate of medication into the pump is restricted by a wick restrictor.