IV vs. Oral vs. Intramuscular vs. Intranasal Ketamine: Why Route Matters
Estelle Autissier, RN
At Principium Psychiatry, we offer our patients cutting-edge treatment options for their depression, and one of our main stars is IV (intravenous) ketamine. But why does it have to be IV? “I don’t like needles, why can’t I just take this as a pill or as that nasal spray everyone is talking about?” you may be thinking. IV is the best route for your brain to receive ketamine because of something called bioavailability. In addition, it is also more effective, more precise, and safer for you.
What is bioavailability? It is the amount of medication that your body and brain is actually able to use, which is sometimes different from the amount of medication that your body receives. When you take any medication, parts of the active ingredients in them don’t go to your bloodstream; they get digested, altered into an unusable form, metabolized and excreted into your body. This is particularly prevalent in oral and intranasal medications. In fact, receiving a medication intravenously is the only way to have 100% bioavailability. Let’s take a look at the different bioavailability percentages based on what route you receive ketamine:
Intravenous: 100%
Intramuscular: 93%
Intranasal: 25-50%
Sublingual (under the tongue): 30%
Orally (by mouth): 16-24%
When we give ketamine intravenously, we know exactly where your entire dose is going: straight to your brain. The same cannot be said for other forms of ketamine. Intranasal ketamine has to bypass several layers of tissue before it can reach your brain, and too many things can happen that could cause you to lose some or most of your dose: sneezing, dripping, running down the back of your throat, etc. The same can be said for an oral pill and an intramuscular injection; these routes are just too unpredictable, and when it comes to treating your depression, we don’t want the results to be unpredictable.
When you receive IV ketamine in our office setting, it is given slowly over one hour. By doing this, we are able to monitor you closely, and if you experience any unpleasant side effects and want to stop the infusion, we are able to do that. By contrast, a dose of ketamine via intranasal spray would be done at home with no physician or nursing supervision, so side effects cannot be immediately addressed if they arise. The same is true for intramuscular or oral dosing — after you take the pill, or receive a shot of ketamine into your muscle, there is no way to stop the absorption of the medication into your bloodstream as the full dose is administered within seconds.
IV ketamine is by far the safest and most effective approach in using ketamine to treat depression. You are in a comfortable setting with healthcare providers with you the whole time, the potential for side effects is low, and you are certain that the dose you receive is the dose that is going to your brain, maximizing the benefits of this cutting-edge treatment.
