Ketamine Therapy for Chronic Pain

 

What is ketamine?

Ketamine is a unique, 60 year old anesthetic used widely in Anesthesia and Surgery and in Veterinary Medicine. Ketamine is considered the safest of anesthetics because it doesn’t suppress respiraction or decrease the output of the heart, as typically happens with narcotics, propofol, benzodiazapines or inhaled anesthetics. It is thus ideal for burn and trauma victims, obstetric hemmorhage and other high risk surgical procedures.

In higher doses Ketamine can produce what is known as a ‘dissociative state’ where the patient appears to be in an unresponsive trance. Ketamine can produce vivid dreams and a feeling that the mind is separated from the body. This effect, called “dissociation,” is also produced by the related (but illegal) drug PCP. When ketamine is used in human medicine, it is often given with sedative drugs to offset these effects.

 

What chronic pain is treated with ketamine infusions?

Ketamine infussions are used to treat therapy-resistant chronic pain syndromes. These include the following:

- Complex Regional Pain Syndrome (CRPS)

- Peripheral Nerve Damage

- Neuropathic pain

- Chronic cancer pain

- Trigeminal Neuralgia (facial pain)

- Diabetic neuropathies

- Post Herpetic Neuralgia

- Fibromyalgia

- Post-Amputation stump pain

- Glossopharyngeal neuralgia

 

Can I buy ketamine?

Ketamine is legally available only to veterinarians and medical doctors for medical use. The ketamine sold illegally on the street or in clubs is often stolen or diverted. Illegally purchased Ketamine is often cut with other substances or may not be Ketamine at all. Ketamine has been used for its mind-altering effects since the 1970s. In the 1990s Ketamine became known as a “club drug” for its use in the dance club scene. Street names include Special K, K, Ket, Vitamin K, Cat tranquilizers.

Unfortunately, the high cost of legal Ketamine is driving patients to the black market. However, snorting or swallowing illegal rave drugs doesn't produce the same results as ketamine infusions and also is associated with the risk of buying a drug of questionable quality under risky circumstances and may be cut with some other substance, or not even ketamine at all.

 

Who can't use Ketamine infusions?

Some individuals with specific medical conditions may not be be appropriate candidates for this type of therapy and they would include anyone with:

- Hypersensitivity (allergy) to ketamine

- A recent myocardial infarction – less than 6 months ago

- Unstable Angina or Accelerated Hypertension

- Uncompensated congestive heart failure/pulmonary hypertension

- Known or suspected Cerebral Aneurysm or AVM

- A recent hemorrhagic stroke – less than 1 year ago

Several medications are known to compete at the NMDA and/or D2-3 receptor and therefore limited the clinical effectiveness of ketamine, these include:

- Risperdal (risperidone),

- Zyprexa (olanzapine),

- Lamictal (lamotrigine).

Any patient currently on these medications would require a downward titration leading to a temporary discontinuation for approximately 2 weeks before the infusion series and during the course of ketamine therapy. The medication may be resumed following completion of the infusion series if clinically indicated.

Also the use of benzodiazepines (Valium, Xanax, etc.), are “relative contraindications” and may need to be reduced prior to treatment for maximal benefit. Benzodiazepines are not exclusionary for ketamine treatment. However, patients with anxiety may need a lower starting dose and more gentle dose adjustment over the course of treatment.

 

How effective IV ketamine for acute pain management?

Because of its high lipid solubility, ketamine rapidly crosses the blood-brain barrier, provides quick onset of action. Ketamine represents a lucrative analgesic modality in the emergency department (ED), particularly in patients with opioid-resistant pain (vaso-occlusive pain crisis in patients with sickle cell disease or patients with chronic pain) or polytrauma patients who are hemodynamically unstable.

Read more about the results of the study and the doze of Ketamine for ED pain management at www.medscape.com/viewarticle/781463

 

Will my current medications interfere with my ketamine infusions?

- Lamictal (generic name Lamotrigine). Patients should allow 12 hours between taking lamictal and the start of their infusion. They should wait 6 hours after their infusion before resuming lamictal.

- Any MAOIs. Some common brand names are Isocarboxazid (Marplan), Phenelzine (Nardil), Selegiline (Emsam), and Tranylcypromine (Parnate). Patients cannot take any MAOIs within 2 weeks of an infusion.

- Patients taking large doses of benzodiazepines will have a reduced response to ketamine. Some common brand names are Xanax (Alprazolam), Ativan (Lorazepam), Valium (Diazepam), and Klonopin (Clonazepam). You can still receive ketamine treatment while taking benzodiazepines. It is perfectly safe, we just want to ensure the best possible chances for your success. You may skip a dose 24 hours before the start of your infusion and wait until 6 hours after before resuming your benzodiazepine.

SSRIs and tricyclics do not interfere with ketamine. There is no need to stop them.If you are taking opiates, muscle relaxers, or anti-inflammatories, there is no need to adjust your dose. You should not adjust your dose or frequency of use of any prescribed medication without first consulting with your prescribing physician.

 

Is ketamine addictive?

The dosages of Ketamine administered in our treatments are a small fraction of the doses used by drug abusers.

Although uncommon as a drug of abuse, Ketamine can be habit forming. Regular users of ketamine become tolerant to the dissociative effects of the drug, meaning more and more is needed to achieve the same effect. Some people do become addicted, and continue to use ketamine even when they plan not to or despite its negative effects. It is not clear whether people who are addicted to ketamine experience any symptoms of withdrawal when they stop taking the drug.

 

Is ketamine dangerous?

If not used under the care of health professionals in a medical setting, users of ketamine put themselves at risk in a number of ways:

- Ketamine can prevents users from noticing pain. This means that if injury occurs, a person may not know it. People under its effects may be confused about their surroundings. Ketamine-related injuries and fatalities are often the result of falls and other accidents.

- Ketamine causes pronounced ataxia (stumbling gait), resembling alcohol intoxication, and can easily lead to falls and accidents.

- Ketamine has been labeled a “rape drug.” This is because it can be slipped into someone’s drink without the person’s knowledge, and its effects can render the person unable to resist sexual assault. This is not a risk at normal therapeutic dosages for depression.

- Ketamine raises heart rate and blood pressure, which can increase the risk of stroke or heart attack.

- Frequent use of ketamine may cause bladder problems (ulcers in the bladder).

- The ketamine sold at clubs may be mixed with other drugs. Taking ketamine with other drugs can have unpredictable and sometimes dangerous effects.

- Driving or operating machinery while under the influence of ketamine, or any drug, increases the risk of physical injury to the user and to others.

 

How does ketamine make you feel?

At low doses, ketamine can have stimulant effects, but most patients describe it as pleasant, relaxing, deep or "spiritual" helping them to see their lives in a new light and  put things into a different perspective.

Most common side effects experienced during the treatment are: sedation, dry mouth, mild euphoria, vivid dreams, nausea and occasional vomiting, blurred vision, dizziness, dissociative experiences, disrupted motor skills, increase in heart rate, increase in blood pressure, deep breathing, increase in blood pressure in lungs, temporary anxiety.

Visual experiences can include blurred vision, seeing “trails,” and mild auditory hallucinations (like hearing a sound similar to a seashell on your ear). Users report a sense of floating, dissociation and numbness in the body. Some report feelings of an “out-of-body” experience. Dissociative experiences during ketamine treatment are very uncommon and in some cases may be unpleasant. Most patients describe dissociative symptoms as "interesting" , "unusual" or "weird".  High doses can cause dissociation with intense hallucinations which can be frightening and upsetting.

 

How are Ketamine infusions given?

Ketamine infusions may be given within or outside the hospital setting.

1) LOW-DOSE AWAKE TECHNIQUE. Patients are required to stay inside the hospital for several days for inpatient ketamine infusions. Ketamine is given through an intravenous (IV) line and started with a 20mg dose of ketamine per hour, which is then increased to a maximum of 40mg of ketamine per hour. Other medications may be used to treat nausea, vomiting and headache throughout the procedure. Fatigue may be common, and may be accompanied by transient periods of hallucinations. These symptoms will fade as the dose is tapered (lowered).

2) COMA TECHNIQUE. This procedure is currently not practiced in the United States. It is more commonly performed in Germany and Mexico.

3) OUT-PATIENT TECHNIQUE, that as of yet has proven to provide only very temporary relief. Patients are given 70mg to maximum of 200mg daily for 10 days in tapered doses. Fatigue may also occur, but there are no reported long term side effects for outpatient ketamine administration.

 

What should I expect during my ketamine therapy sessions?

The amount given will not cause you to lose consciousness. During the infusion, most patients have a mild dissociative experience, with an increased sensitivity to light and sound and an altered perception of time and color. Most patients tolerate these experiences without discomfort and many people find them to be pleasant. In the rare case these side effects are considered unpleasant, other rapid acting medications can be used to relieve or eliminate this discomfort. Once the infusion is complete, the dissociative effects of the drug rapidly dissipate and are often mostly gone within 20-30 minutes.

 

What side effects I should be concerned about?

Patients commonly feel tired following a ketamine infusion. On rare occasion, some patients experience nausea after an infusion. If you are prone to nausea, a prophylactic might be administered before the infusion to help prevent it. Side effects usually dissipate within a few hours and are completely gone by the following day. There are no known long-term or permanent side effects of IV Ketamine Infusion Therapy.

 

What are the codes for ketamine infusion?

If you would like to call your insurance company about the insurance coverage for your ketamine infusions, the 2009 Coders' Desk Reference lists the following CPT codes for "Therapeutic Intravenous Infusions"

96365 - first hour

96366- each additional hour.

 

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