Drug delivery apparatus and method for automatically reducing drug dosage

Abstract

A drug delivery device which includes a fluid drug reservoir, a catheter, a controllable fluid transfer device, e.g., a pump mechanism or valve, and a drug delivery control means. The drug delivery control means comprises a controller, e.g., a microprocessor or microcontroller which is operable to automatically reduce the rate of drug delivery over a certain reduction interval (e.g., multiple days) from an initial dosage value to a final dosage value.

1 . A fluid drug delivery device comprising: 
 a reservoir for storing a fluid;    a catheter for transferring fluid from said reservoir to a selected body site, said catheter having a proximal end for receiving fluid from said reservoir and a distal end for delivering fluid to said body site;    a controllable fluid transfer device coupling said reservoir to said catheter proximal end;    a controller storing data defining a delivery rate specifying a quantity of fluid to be delivered to said catheter within a specified period;    a source of modification data;    said controller being responsive to said modification data for iteratively modifying said stored delivery rate; and wherein    said fluid transfer device is responsive to said modified delivery rate for delivering a specified quantity of fluid to said catheter proximal end.    
   
   
       2 . The delivery device of  claim 1  wherein said controller includes a programmable microprocessor; and wherein 
 said controller includes means for executing an algorithm to iteratively reduce said stored delivery rate based on said modification data.    
   
   
       3 . The combination of  claim 1  wherein said drug delivery device comprises an implantable pump; and further including 
 a clinician operable programmer external to said drug delivery device for transmitting said modification data.    
   
   
       4 . The combination of  claim 3  wherein said drug modification data defines a periodic reduction ratio; and wherein 
 said controller iteratively processes the stored delivery rate and said reduction ratio to produce a modified delivery rate.    
   
   
       5 . The combination of  claim 4  wherein said reduction ratio has a value less than one; and wherein 
 said controller processing includes multiplying the stored delivery rate times said reduction ratio.    
   
   
       6 . The combination of  claim 4  wherein said modification data defines a periodic reduction ratio having a value less than one; and wherein 
 said controller stores a current delivery profile defining at least one delivery rate; and wherein    said controller operates to iteratively multiply said periodic reduction ratio times each delivery rate in said current delivery profile to produce a new delivery profile.    
   
   
       7 . The combination of  claim 1  wherein said modification data specifies a number of periodic reduction steps and a reduction ratio having a value less than one; and wherein 
 said controller multiplies said stored delivery rate and said reduction ratio for each of said reduction steps to successively produce new and reduced delivery values.    
   
   
       8 . A method of operating an implantable drug delivery device for transferring a drug from a reservoir to a catheter for delivery to a body site, said method including: 
 providing said reservoir with a first drug;    storing a current dosage value;    generating dosage modification data;    periodically modifying said stored dosage value in accordance with said dosage modification data; and    controllably transferring said first drug from said reservoir to said catheter in accordance with the currently stored dosage value.    
   
   
       9 . The method of  claim 8  wherein said step of periodically modifying comprises iteratively reducing said stored dosage value.  
   
   
       10 . The method of  claim 8  wherein said step of generating dosage modification data includes calculating a rate reduction ratio; and wherein 
 said step of periodically modifying comprises iteratively multiplying said stored dosage valve times said reduction ratio.    
   
   
       11 . A fluid drug delivery system comprising: 
 an implantable drug delivery pump including a controller for transferring a fluid drug from said pump at delivery rates defined by a stored drug delivery profile;    an external programmer for generating drug delivery modification data;    and wherein    said controller includes means responsive to said drug modification data for iteratively modifying said defined delivery rates as a function of said modification data.    
   
   
       12 . The system of  claim 11  wherein said modification data specifies a discrete number of modification steps and a modification ratio for each of said steps; and wherein 
 for each of said steps said controller modifies the stored drug delivery profile as a function of said modification ratio to successively define modified delivery rates.    
   
   
       13 . The system of  claim 12  wherein said modification data specifies a discrete number of reduction steps and a reduction ratio for each of said steps having a value less than one; and wherein 
 for each of said steps said controller modifies the stored drug delivery profile as a function of said reduction ratio to successively define reduced delivery rates.    
   
   
       14 . The system of  claim 13  wherein said programmer includes processor means for calculating said reduction ratio.  
   
   
       15 . The system of  claim 14  further including telemetry means for communicating said calculated reduction ratio to said pump controller.  
   
   
       16 . The system of  claim 11  wherein said drug delivery pump further includes a fluid reservoir and a fluid transfer means for transferring fluid from said reservoir to a patient's body site; and wherein 
 said controller controls said fluid transfer means in accordance with said defined delivery rates.