Drug delivery apparatus and method for automatically reducing drug dosage
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.