a) Absorption works within 2 hours, effect lasts 1-2 weeks
Oral (PO) Bioavailability = 20% due to 1st pass liver metabolism
Topical (TD) - creams and gels for local pain relief
c) Metabolism - CYP3A4 - with Grapefruit juice 12 X Level, after 24 hours 2.4 X level, 3 days 1.5X, 7 days = same
Ketamine binds to and inhibits the NMDA Receptor (NMDA-R).
The S(+) and R(-) stereoisomers bind with different affinities: Ki = 3200 and 1100 nM, respectively.
also Opiate Agonist
Ketamine has been tested in
1) Major Depressive Disorder
2) Treatment-Resistant Bipolar Depression, and
3) Emergency room Suicidal Patients
potential Adverse Effects
Cardiovascular: abnormal heart rhythms, slow heart rate or fast heart rate, high blood pressure or low blood pressure
Dermatologic: Transient erythema, transient morbilliform rash
Gastrointestinal: Anorexia, nausea, increased salivation, vomiting
Local: Pain or exanthema of the injection site
Central nervous system: Ketamine is traditionally avoided in people with or at risk of intracranial hypertension (ICP) due to concerns about ketamine causing increased intracranial pressure. It does not increase ICP more than opioids.
Neuromuscular and skeletal: Increased skeletal muscle tone (tonic-clonic movements)
Ocular: Double vision, increased intraocular pressure, nystagmus
Respiratory: Airway obstruction, apnea, increased bronchial secretions, respiratory depression, laryngospasm
Other: Anaphylaxis, dependence, emergence reaction
Urinary & Bladder - One patient had bladder problems from the medical use and when it was discontinued, the symptoms resolved.
Psychiatric: Hallucinations, confusion, disorientation up to 24 hours after dose
Dose of ketamine for Anesthesia is about 2mg per kilogram (2.2 pounds) of body weight.
This dose usually causes loss of consciousness, and has minimal therapeutic effect
Dose of ketamine for Psychiatric Ketamine Treatment is much less, about .25 -.5 mg/kg
This dose not cause loss of consciousness, and has more therapeutic effect
the Therapeutic effect of ketamine is variable, for some people there is almost no effect, but for many people there is a complete remission of symptoms. Even when an excellent effect is obtained, it is not permanent, for some people it lasts weeks, but for others it only lasts 3-8 hours