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Overview of Ketamine Infusion Therapy
By Philip Getson, DO
Patricia Curiale led an active life until an auto accident
in 1998 triggered CRPS. After five years of living with
pain that she rates "50 on a scale of 10," she was
enrolled in our outpatient program that uses ketamine to treat
CRPS when other conventional treatments fail. Ketamine
is an anesthetic typically used in the operating room and
for victims with unknown medical history (eg, traffic accidents).
Ms. Curiale frankly credits the ketamine with saving her life.
"I can understand putting a gun to your head to stop
the pain," she says. Although she currently rates her
pain at "about a 5," she can live with that. Plus,
she has been able to get out of her wheelchair and walk, something
a previous physician swore would never happen.
She is one of many people who have CRPS and who have taken
part in a program that I run with Robert J. Schwartzman, MD,
Drexel University College of Medicine in Philadelphia. Currently
we are collecting data on an outpatient "awake"
ketamine protocol for patients who have tried more conventional
therapies without long-term benefit.
Elena King-Stoltz, who has full-body CRPS, had tried Bier
blocks, spinal blocks, an intrathecal pump and other treatments
since being diagnosed in 1992, but still experienced high
levels of pain. She has been on the ketamine program for almost
a year now. "I mowed my lawn for the first time in 10
years," she says.
The program can be done on both an inpatient and outpatient
basis. Before beginning either therapy, we do laboratory and
cardiac evaluations. While we have had No significant adverse
events, we have been extremely cautious in screening patients
with concurrent medical problems. The two most common reasons
a patient would be eliminated are a psychiatric history of
note (apart from the depression due to chronic pain) and cardiopulmonary
disease.
Hospital-based infusions
The hospital-based infusions require a five-day in-patient
stay. An intravenous (IV) line is inserted and the patient
is started on a dose of 20mg of ketamine per hour, which is
increased by 5- increments to a maximum of 40mg per hour.
As an adjunct, we are using clonidine, 0.1mg (per FDA). We
use small doses of lorazepam (Ativan®), 1 to 2 mg, for
any dysphoria or hallucinations.
The most common adverse event is fatigue. There have been
some instances of short-term hallucinations related to dosage,
but these have disappeared within an hour of lowering the
dosage.
Pat found the ketamine treatment very draining and the drug
left her feeling "loopy," but she saw results from
the beginning. She stopped the treatment in the fall of 2005
at her request. In addition, she had been taking oral ketamine
but stopped a couple of months ago because she felt it was
affecting her ability to concentrate.
The accumulated data over two years denotes no significant
lasting adverse events. Dr. Schwartzman and I have treated
more than 100 patients. We had one patient with bradycardia
in which the 5-day infusion was terminated.
Following discharge from the hospital, patients enroll in
an outpatient infusion program of varying degrees and lengths.
Initially, they go to the hospital's outpatient department
1-to-2 times a week for a 4-hour IV infusion of 70mg-to-100
mg of ketamine. At the beginning of the infusion, the patient
is given 2mg of midazolam. Most patients sleep through the
procedure. The frequency of outpatient treatments is weaned
over time. Currently, we are using a protocol that consists
of two outpatient treatments a week every other week for one
month, then one treatment every other week for a mont then
monthly for three months then every three months. this protocol
is merely a general guideline however and varies at times.
then one outpatient treatment the following month, after which
we reassess the patient. Outpatient visits are then monthly,
or at 3-month intervals, depending on the patient.
Out-patient protocol
Alternatively, the patients are given therapy only on an outpatient
basis. They are given 10 daily treatments initially in two
consecutive weeks in an outpatient infusion suite. They are
administered from 70mg-to-100mg of ketamine per day in titrating
doses over the 10-day timeframe and then they are placed in
the outpatient program as described above. Again, there have
been few adverse events and most of them have been dosage-related.
As before, the most common is fatigue on the day of the infusion.
There have been NO long term side effectsMost patients are
given 2mg of midazolam and sleep through the procedure.
Ms. King-Stoltz, an exception to the aforementioned protocol
does the outpatient protocol once or twice a week. She spends
4 hours in the hospital and says she has no serious side effects.
She is a little tired afterwards, but it goes away quickly.
Results
The results obtained so far have been promising. We measure
outcomes using pain scales, physical exams, psychologic profiles,
and activity increase.
Rough estimates shows approximately 85% of those undergoing
the hospital-stay protocol have shown improvement measured
by increased activity, reduction of medication, and improved
lifestyles. For example, some have discarded wheelchairs,
walkers, and canes, and others have increased activities or
have returned to work. Those beginning with outpatient therapy
have similarly improved, but to a lesser degree (approximately
60% to 70%). All patients receive the follow-up outpatient
boosters.
Ms. King-Stoltz says that although she still has pain, it
is manageable and she is doing things she hadn't done for
years, such as walking and doing chores around the house.
The ketamine treatment has given her back some degree of independence.
The one major problem with ketamine infusion therapy is the
inability to "hold" the improvement achieved by
the five-day inpatient or 10-day outpatient regimen. Without
the infusion boosters, the patients almost universally return
to their pre-treatment state. It is therefore necessary to
combine the initial start-up therapy on an inpatient or outpatient
basis with follow-up boosters in order to maintain the level
of pain relief.
Virtually all participants in the program have continued the
out-patient ketamine infusions. None of the patients treated
by Dr. Schwartzman and myself have discontinued treating due
to side effects.
More study will be necessary to determine such factors as
dosages and long-term time frame to be treated. Studies are
currently ongoing to combine other drugs on an outpatient
basis with ketamine to try and "hold" the improvement
for a longer duration. Most patients get sustained relief
for 4 to 6 months. Some have been fortunate enough to get
a longer term benefit.
I believe that ketamine provides the best chance of improvement
from a therapeutic modality today. While it involves the use
of medications besides ketamine, the use of IV drug therapy,
a great deal of time and effort on the part of the patients
and their families, it has certainly shown great promise in
patients who do not find relief from other treatment.
Certainly the drug is not for everyone-approximately 20% of
people show little to no improvement. However, some have benefitted
dramatically. We continue the treatment program in the hope
that more patient evaluations and the use on concurrent medication
can affect a more long-lasting improvement in individuals
with multi-limb or multi-system disease. For now, however,
we at least appear to be heading in a positive direction,
helping many individuals who, up to this point in time, have
received no or little benefit from the more "conventional"
treatment modalities.
Philip Getson, D.O. is a Board Certified Family Practitioner
and an Associate Professor OF Neurology at the Drexel University
college of Medicine in Philadelphia. He can be reached at
856-983-7246 or PGetson@AOL.com
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