Abstract:
The oral medication delivery device provides patient access to medications prescribed to be available on an as-needed basis, but with a minimum time intervals between doses. The required time interval between drug accessibility is programmed into the device when the medication tray carrying the multiple doses is loaded into the device. The device allows access to a single dose of the medication after each minimum time interval has elapsed. When the drug dose is removed from the device, the medication tray locks until the next minimum time interval has elapsed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This patent application claims the benefit of the provisional patent application No. 60/323,521 filed on Sep. 19, 2001. 

   FIELD OF THE INVENTION 
   The present invention relates generally to an oral medication dispenser, and more particularly to a time controlled oral medication dispenser. 
   BACKGROUND OF THE INVENTION 
   Fifty percent of postoperative patients report inadequate pain relief. Fifty percent of all cancer patients and ninety percent of advanced cancer patients experience pain. Pain is now defined as “the fifth vital sign” as part of the mandate by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) to develop guidelines for pain management. 
   Adequate pain control requires the appropriate medication for the pain level and type reported. In a hospital setting, pain medication can be obtained only by a physician&#39;s order. Pain medications such as narcotics and nonsteroidals (and anxiety medications such as tranquilizers) are frequently ordered on an as-needed basis (referred to as prn orders). This approach requires the patient to initiate a request for each prn drug dose. The nurse then verifies that the appropriate time interval has passed between doses, according to the physician&#39;s order. If the required time interval has elapsed, the nurse transports the medication to the patient&#39;s bedside and administers the medication to the patient. In some dosing regimens the patient is given a time release pain medication at the same time(s) each day with as-needed (prn) medications for breakthrough pain. Again the patient must request the medication for each breakthrough pain episode. A common reported patient frustration is the need to issue a request for each and every dose of prn medication. Thus a busy nurse must locate the medication and transport it to the patient in response to each request. This must also be accomplished in a timely fashion as patients in pain must be administered to as soon as possible. 
   The as-needed approach to dosing provides the minimum amount of medication to adequately control symptoms, without the risk of abuse, overdosing and unnecessary side effects. Disadvantageously, in a hospital or institutional setting each medication that is dispensed on a prn basis requires nursing staff time and extra documentation by nursing and pharmacy staff, since the drugs can be administered only after the lapse of the predetermined time interval between doses. For example, a drug prescribed as needed every six hours may be given no more than four times in 24 hours. Such a drug may be administered from zero to four times in any given 24 hour period, depending upon patient dosage requests. If six hours have passed since the last administration of the drug, the medication is provided to the patient in response to the request. If six hours have not lapsed, the patient must wait the minimum time interval of six hours prior to receiving the next drug dose. In a home setting, the patient must remain aware of the restricted dosing schedule to safely self-administer these medications. 
   An automated bedside dispensing cabinet, requiring the nurse to enter the cabinet at times to dispense medications, is known. As with all prn medications this device requires the nurse visit the patient&#39;s room. The medication is removed from the cabinet for dispensing. Although such a device reduces medication errors compared to the conventional approach, it expends valuable nursing time and expense. 
   It is also known that oral medications may be provided through the use of a sealed wrist pouch. The pouch is worn by the patient and filled with two medication doses. The pouch is refilled by a nurse at the patient&#39;s request. The patient reports the time of each self-administered dose and maintains a pain control diary. As in the other prior art devices, nursing staff time is required for refills and nursing staff availability may disrupt timely refilling of the pouch. 
   Drug delivery devices are known that remind the patient to take a medication at preset time intervals. These devices provide the reminder through a variety of signaling indicators, such as audible alarms, and promote compliance to a scheduled dosing regimen, but do not control nor prevent patient access to the medications at intervals shorter than prescribed. 
   Known PCA (patient controlled analgesia) intravenous pumps allow patients to self-medicate with pain medications. Using a PCA pump, under a physician&#39;s order, a patient receives a single dose of intravenous medication by activating a bedside button. The actuation starts a pump that delivers a measured dose of the intravenous drug (a narcotic, for example) at allowable time intervals. If the button is activated during a time interval in which an allowable dose has already been administered, the pump is “locked out” and unable to deliver the dose until the appropriate time interval has passed. This prevents the patient from taking more than a maximum allowable dose of medication during a measured time interval. The PCA device records the drug volume delivered over time. A nurse can query the device to chart the volume of drug delivered over a given time interval and the number of doses administered. 
   Two other dosing devices are available using the same principal as the intravenous PCA. These include pumps that deliver narcotic medications subcutaneously and epidural catheters that deliver pain medications near the spinal canal. Cancer patients experiencing both acute and chronic pain use such intravenous PCA pumps. 
   A randomized study of pain management in a post-operative setting using patient controlled analgesia (that is, the PCA pump) versus conventional pain therapy (CPT) (i.e., a request to the nurse for each administered dose), has been reported in the medical literature. Patient satisfaction for pain management in the PCA group was significantly better than that reported in the CPT group. Note, the only difference between the two study groups was the ability of the PCA group to easily and promptly self-control the medication dosing. 
   Multiple factors prevent the timely dosing of pain and other as needed medications to the patient bedside according to conventional pain therapy techniques. A national survey of pharmacy practice in acute care settings in 1999 indicated that 75% of pharmacies still practice centralized pharmacy distribution systems. In some situations, these centralized pharmacies extend the time required to deliver medications to each patient area. A future trend will be automated medication dispensing stations in each patient area. Although this is a trend for the future, it is not as yet reality except in large, sophisticated, primarily academic hospitals. Currently there is a shortage of pharmacists and the existing staffs are over-burdened, creating further delays in drug delivery to the patient bedside. 
   In about 98% of the cases, nurses directly administer medications to patients. A time and motion study has reported that each prn oral medication delivered by a nurse to a hospital patient requires 18.42 minutes, which includes the unlocking of the narcotics cabinet to sign out the medication, transporting it to the patient&#39;s bedside, and documenting (charting) the time the dose is given. Like the pharmacy staff, nursing staffs are short-handed, while the number of complex hospitalized patients is growing. These patients have increasingly more complex diagnoses with more medication requirements. 
   Improved patient pain control leads to better patient outcomes in the hospital setting. This has been well documented in the surgical literature in the postoperative setting, with fewer postoperative complications, earlier rehabilitation, and shorter hospital stays in patients with better pain management. Better pain management is also highly cost effective since earlier discharges and few complications save dollars and staff time. 
   BRIEF SUMMARY OF THE INVENTION 
   The medication on demand device of the present invention offers controlled self-medication by the patient and thus promotes patient autonomy by allowing access to the medications on an as-needed basis. However, a second dose can be delivered only after a required minimum time has elapsed from a first dose. The device includes a timing mechanism that permits patient access to the next dose only after a specified dosing interval as prescribed by a physician&#39;s order. Once the dosing interval has elapsed, access to the next medication dose is provided using a unique keypad-operated entry code entered by the patient. 
   When used in a facility setting, this device promotes patient autonomy and a more efficient drug delivery process, without the delay associated with nursing delivery of the drug and the attendant nursing staff record-keeping. Thus the amount of time consumed by nursing and pharmacy staff to deliver and document each drug dose is reduced. However, the nursing staff is able to chart the time at which doses were administered from time data recorded on the device. Since the medications are loaded into the device of the present invention in a cassette carrying multiple doses, the pharmacy can deliver multiple doses as one item, thus also reducing the drug handling and inventory requirements of the pharmacy. 
   The device of the present invention can be used for any application of oral pain management in a hospital, nursing home, hospice or assisted living facility. In addition to patients suffering chronic pain, many postoperative and trauma patients, as well as patients in rehabilitative facilities, require as-needed oral pain medication and thus can benefit from use of the present device. In a home setting where dosing intervals are patient-monitored, use of the medication on demand device of the present invention avoids overdosing and relieves the patient of the need to monitor the time between drug doses, since the device permits access only after the ordered minimum time has elapsed. Although reference is made to the delivery of pain medication using the device of the present invention, the device can also deliver other drugs, such as tranquilizers and anti-nausea medications, or any other drugs that are administered on a prn basis. 
   The medication dispensing device can interface, through a suitable network, with an automated drug dispensing, inventory, and billing system. This application allows the device to function as a “mini satellite” at the patient&#39;s bedside, as one element of a larger automated pharmacy system located in each patient area. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other features of the invention will be apparent from the following more particular description of the invention, as illustrated in the accompanying drawings, in which like reference characters refer to the same parts throughout the different figures. The figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
       FIG. 1  is an exploded view of a medication on demand device constructed according to the teachings of the present invention. 
       FIG. 2  is a block diagram of the control components of the medication on demand device of FIG.  1 . 
       FIG. 3  is another exploded view of a medication on demand device constructed according to the teachings of the present invention. 
       FIGS. 4 and 5  are top and bottom views, respectively, of the medication on demand device of  FIGS. 1 and 2 . 
       FIG. 6  is a top view of another embodiment of the medication on demand device. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Before describing in detail the particular medication dispenser in accordance with the present invention, it should be observed that the present invention resides primarily in a novel combination of hardware and software elements related to a medication dispenser. Accordingly, the elements have been represented by conventional elements in the drawings, showing only those specific details that are pertinent to the present invention, so as not to obscure the disclosure with structural details that will be readily apparent to those skilled in the art having the benefit of the description herein. 
   A medication on demand device  10  constructed according to the teachings of the present invention is illustrated in the exploded view of  FIG. 1 , comprising an upper assembly  12  for mating with a lower assembly  14  and capturing a medication tray  16  there between. The medication tray  16  is received by an upper surface enclosure  17  of the lower assembly  14 . In one embodiment a motor (not shown in  FIG. 1 ) is located within the upper surface enclosure  17 . A gear  18  attached to the motor shaft protrudes from the vertical surface  19  of the upper surface enclosure  17  for drivingly mating with a circumferential gear track  21  disposed on an inner surface  22  of the medication tray  16 . Thus rotation of the gear in response to the application of electricity to the motor causes rotation of the medication tray  16 . 
   The upper assembly  12  includes a passage  18  for receiving a door (not shown in  FIG. 1 ) providing access to one of a plurality of medication compartments  20  of the medication tray  16 . Once the patient has opened and closed the door to remove the medication, a timing sequence is initiated and during that sequence the medication tray  16  is locked in place. After the interval has elapsed, the medication tray  16  is rotated, through action of the motor and associated gearing, through an arc segment to align the passage  18  with the next one of the plurality of medication compartments  20 . As described further below, the medication tray  16  is signalled to rotate via entry of a patient code on a keypad of the device  10 . The patient can then remove the next dosage for self-administration. 
   In the embodiment of  FIG. 1  each one of the plurality of equally-sized medication compartments  20  carries a medication dose for administration to the patient. Preferably, the upper assembly  12  is translucent or transparent and the lower assembly  14  is opaque to provide a color contrast, making the medication easily visible within the plurality of medication compartments  20 . In another embodiment a color-coded medication tray serves as an indicator of the drug type carried there within. In the pharmacy, the medication tray  16  can be loaded with medications, labeled to identify the patient and the minimum dosing interval, and provided to the nurse attending the patient. While being transported, the medication tray  16  can be covered with a disposable cover. 
   A controller  30  (see  FIG. 2 ) and its associated components control rotation of the medication tray  16  and allow patient access to the medications. In one embodiment the controller  30  is a microchip-based controller programmed to perform the various functions described herein. When the medication tray  16  is loaded into the device  10 , the nursing or pharmacy staff enters the physician ordered dosing interval via an input device  34 , comprising in one embodiment one or more manually operable switches. The controller  30  is responsive to the input device  34  for receiving and storing the dosing interval. The nursing staff also enters an authorization code, via the input device  34 , that is stored in the controller  30 , for later use to limit medication access to the patient for whom the medications are intended. 
   Although the description herein generally refers to a nursing staff as the party exercising control over the operation of the device  10 , this function can be performed by any third party ultimately controlling the patient&#39;s medication dosing, such as an in-home care giver, medical technician, pharmacy staff member, physician, etc. 
   The controller  30  is further bidirectionally responsive to a timer  36  for monitoring the time interval between permitted doses, and to a door sensor  38  (see  FIG. 1  for the physical location thereof) for determining the door position. From the door position information, the controller  30  determines the times when the door is opened and closed by the patient to receive the medication for self-administration. After the patient has sequenced the door through an open and close cycle to remove the medication dose, the controller  30  activates the timer  36  to begin a counting sequence representing the dosing interval. When the timer  36  times out, the dosing interval has elapsed and the patient is permitted to administer the next dose. In response thereto, the controller  30  illuminates an indicator  40  (see also  FIG. 1 ) indicating that the dosing interval has elapsed. In one embodiment the indicator  40  comprises a light emitting diode. The embodiment illustrated in  FIG. 1  includes a second indicator  41 , not required for proper operation of the device  10 , that is illuminated during the dosing interval, serving as an indication that the patient is not permitted to administer the next medication dose. 
   Returning to  FIG. 1 , note that the upper surface enclosure  17  further carries a keypad  42  comprising a plurality of user-operable keys for entering an authorization code. After the indicator  40  is illuminated, the patient uses the keypad  42  to enter a predetermined code that is supplied as an input to the controller  30 . In one embodiment, the code comprises four digits and is followed by entry of an “enter” command on the keypad  42 . If the entered code matches the stored authorized code, previously entered by the nursing staff as described above, in response thereto the controller  30  energizes a motor  44  to cause rotation of the medication tray  16 , as described above, such that the next medication compartment  20  is aligned with the passage  18 . The patient now has access to the next medication dose. In one embodiment the motor  44  comprises a stepping motor that when energized controllably rotates only through a predetermined number of turns such that the next medication tray  20  and the passage  18  are aligned. 
   The dosing timing cycle begins again when the door sensor  38  senses the opening and closing of the door, provides representative signals to the controller  30 , and the controller  30  activates the timer  36 . 
   If the patient&#39;s pain has subsided and he thus does not require a medication dose at the prescribed minimum interval, i.e., when the indicator  40  is illuminated, the patient can elect not to enter the prescribed authorization code. The device  10  remains in a ready condition such that whenever the code is entered the medication tray  16  is rotated and the next dose is accessible. Only an open and closing cycle of the door restarts the timing cycle. 
   Although the patient authorization process described above comprises the entry of numeric or alphabetic characters via the keypad  42 , other identification techniques for determining if the patient is authorized to receive the medication can be employed, including fingerprint and voice print identification. Also a bar code reader can be incorporated into the medication on demand device  10  for reading a bar code assigned to the patient and printed on the patient&#39;s wristband. If the stored bar code in the reader matches the scanned bar code and the minimum dosing interval has elapsed, the medication tray  16  is rotated under control of the controller  30 , as described above, to provide patient access to the next medication dose. 
   The door open and close times determined as described above, are stored within the controller  30  and displayable on a clock  48  (disposed on the bottom surface of the lower assembly  14 ) in response to command queries entered into the input device  34 . Nursing staff can thus query the controller  30  to display the dose administration times, which can then be manually entered in the patient&#39;s chart. In another embodiment where patient records are stored in a computing mechanism and associated storage media, the controller  30  is connected via a wired or wireless network to the computing mechanism for automatically downloading these dose administration times and inputting them to the patient&#39;s record. Alternatively, the clock  48  is operable as a real time clock in response to commands entered into the input device  34  by nursing staff members. 
   Although the timer  36  is described herein as a separate component of the controlling mechanism of the device  10 , those skilled in the art recognize that the timing function can be incorporated within the controller  30 . Likewise, storage of the dosing interval, authorization code, etc., is described with reference to on-board storage in an internal memory within the controller  30 . In another embodiment the device  10  includes external memory responsive to the controller  30  for storing program code and such data. 
     FIG. 2  further includes a key switch  50  for setting the operational mode for the device  10 . In one embodiment the key switch  50  comprises a three-position key switch. A mating key is required to set the position of the key switch  50 . Typically, this key would be accessible only to the nursing staff. In a first position the upper and lower assemblies  12  and  14  are separable for loading a new medication tray  16 . Typically, the device  10  would be loaded with new medications doses every 24 hour period. Other time periods may apply depending on the dosing interval and the number of medication compartments  20 . In a second position the device  10  is locked and ready for patient use. In a third position the dosing interval can be entered through the input device  34  and the controller  30  can be queried as to the times when the door  65  was opened and closed. 
     FIG. 2  further includes a network interface  52  providing a wired or wireless connection to a remote computing device. Various information collected by the controller  30 , such as patient&#39;s dosing times and the minimum dosing interval, is supplied to the remote computing device via the network interface  52 . 
   A more detailed exploded view of the medication on demand device  10  is illustrated in  FIG. 3 , wherein the upper assembly  12  comprises a housing  60 , for receiving a cover  62 . A first portion  63  of the passage  18  is formed within the housing  60  and a second portion  64  thereof is formed within the cover  62 . A door  65  provides access to the passage  18 . 
   The lower assembly  14  further comprises a housing  70  carrying a circuit board  72  on which the controller  30  (not shown in  FIG. 3 ) and its associated components are mounted. The motor  44 , powered by batteries  76 , is mounted within a housing  80 . The key switch  50  passes through a notch  82  in the circuit board  72  and a notch  84  in the housing  80 . The key switch  50  is electrically connected to the controller  30 . 
     FIG. 4  is a top view of the medication on demand device  10  illustrating the previously discussed components. 
     FIG. 5  is a bottom view of the medication on demand device  10  illustrating several of the previously described components of the device  10 . A guide wire  100  for securing the medication on demand device  10  to a patient&#39;s bed, bedside table or tray passes through a loop hole  102 . The input device  34  and the clock  48  are also shown in the bottom view of FIG.  5 . 
   The bottom surface of the device  10  further includes a low-battery indicator  108  and a recess  110  for receiving, for example, patient identification information, the medication type and dosage, and the minimum interval between doses. Typically, this information is recorded on adhesive-backed material received within the recess  110 . The device  10  includes a stacking ring  112  for mating with a receiving recess in the upper assembly  12  of a second device  10 , thus allowing several devices  10  to be transported and stored in an efficient and stable configuration. 
   In another embodiment of the present invention, the door  65  is lockable and controllable by operation of the controller  30 , such that a door lock  120  in  FIG. 6  is released only after the minimum dosing interval has elapsed. In this embodiment, rotation of the medication tray  16  by operation of the motor  44  under control of the controller  30  can occur at any time during the dosing interval, as the patient cannot gain access to the medication until the door  65  is unlocked. 
   While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalent elements may be substituted for elements thereof without departing from the scope of the present invention. The scope of the present invention further includes any combination of the elements from the various embodiments set forth herein. In addition, modifications may be made to adapt the teachings of the present invention to a particular application without departing from its essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.