Routes of Administration
Route of Administration (ROA) refers to the method in which a medication is introduced to the body. Ketamine can be administered via several routes, including:
• Infusion (IV)
• Sprayed into the sinus cavities (intranasal)
• Under the tongue (sublingual)
• Intramuscular injection with a syringe (IM)
• Orally (swallowed)
• Rectally (suppository)
The intravenous (IV) infusion is the most common, the most studied, and probably the safest method of administering ketamine. Obviously, IV is the ROA for ketamine infusions. The ROA, in addition to pharmacokinetics, is incredibly important for all medications when discussing both safety and efficacy. Every anesthesiologist studies this in great detail. This is one of the reasons why ketamine infusions should be performed by anesthesiologists who are fellowship trained in pain management. They should know the anesthesia side of the infusion and the pain side of the patient. They should also be using ketamine infusions as part of a comprehensive treatment program.
Ketamine infusions work the best when they are delivered at a steady IV infusion rate in conjunction with multiple different adjunctive medications. When the correct combination for the patient is achieved, reversal of central reorganization can begin to occur.
Ketamine via intranasal, sublingual, IM, oral, and suppository routes is NOT the same as a ketamine infusion because those routes are usually not under monitored conditions, steady plasma state is not achieved, peak plasma levels can be dangerously high, side effects are higher, efficacy is lower, and addiction potential is higher. Therefore, we do not recommend these routes in the management and treatment of central pain conditions. The IV route allows for great control by the physician administering the infusion (assuming the physician is knowledgeable and experienced, such as a pain fellowship trained anesthesiologist).