Ketamine Pharmacology


1) Pharmacokinetics

a) Absorption  works within 2 hours, effect lasts 1-2 weeks

       Intravenous (IV), 


       Oral (PO) Bioavailability = 20% due to 1st pass liver metabolism

       Sublingual (SL)

       Topical (TD) - creams and gels for local pain relief

b) Distribution

c) Metabolism -  CYP3A4 - with Grapefruit juice 12 X Level, after 24 hours 2.4 X level, 3 days 1.5X, 7 days = same

d) Elimination


2) Pharmacodynamics

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.[69]

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