Skip to main content

Understanding Adrenaline Dosage

Have you ever administered adrenaline for anaphylactic shock? I've never had the unfortunate need to. I'm sure anyone who ever does will forever remember the correct dosage. But for me, it is always a confusion. Every time I vaccinate someone at my clinic, I look up the dose of adrenaline just to be sure.

The first problem is the dilutions. Dosages of adrenaline are (or were) mentioned in dilution. 1:1000 & 1:10000. There begins the confusion.

Firstly, let us understand where the 1000 comes from in 1:1000. Have you seen a small vial of adrenaline? That is 1mL. It has effectively 1mg of epinephrine/adrenaline. But why is it called 1:1000? Because 1mL of water = 1g of water = 1000mg. So, the 1:1000 actually refers to 1mg of adrenaline : 1000 mg of water. Unnecessarily complex!

All you had to say was 1mg in 1mL. And that is why this labeling is now being followed in some countries.

So, there you have a small vial - a 1mL vial - with 1mg of adrenaline in it.

Now, let us look at the other form epinephrine comes in. Epinephrine also comes in a big syringe of 10mL. But even this 10mL contains only 1 mg of adrenaline. The total amount of adrenaline in this 10mL form is the same as a small vial.

What is different then? Well, when the volume increases without increase in amount, the concentration drops. The 10mL form is more dilute than the small vial. Can you guess the dilution? It is 1:10000 or more easily expressed as 1mg in 10mL.

So, the first thing to internalize is that the small 1mL vial we see has 1mg of adrenaline (it may say 1.8mg of an adrenaline salt, but the effective amount of adrenaline is 1mg). And this is a concentrated form of adrenaline.

What that also means is that the 1mg/1mL adrenaline is never used directly IV! The reason is that this can cause an arrhythmia or other damages to the heart muscles.

If you're bored reading text, watch this youtube video telling these same things.

Now, the dilute form and the concentrated form are for slightly different uses. The concentrated form is given IM in anaphylactic shock. The dilute form is given IV in cardiac arrest.

When giving IM adrenaline for anaphylactic shock, the dosage in adults is almost always 0.5mg (0.5mL of the concentrated vial). If you can remember this fact it is easy to calculate the pediatric dose as well. The adult dose can be thought of as if it applies to a 50kg person. So 0.5mg for 50kg = 0.01mg/kg and that is the pediatric dose. (This 50kg adult approximation applies for many other drugs in calculation of pediatric dose. Let me know in comments below about other drugs that can be calculated this way).

When giving in cardiac arrest, in which case the dilute form (1mg in 10mL) is used, the adult dose is the entire 1mg (or 10mL) given intravenous and repeated based on the protocol you follow.

That is all there is to know. Just a 0.5mg and a 1mg.


MaaLuSreya said…
Really awesome explanation by you @Akshay S Dinesh...but 1 more reason for administration of 0.5ml adrenaline IM is due to its ease to administer without wasting time over securing an IV line and putting the patient's life in danger.
MaaLuSreya said…

Popular posts from this blog

What Doctors Don't Get to Study in Medical School by BM Hegde

Disclaimer: I realize that I could be putting myself in great academic danger by publishing this post while studying medicine in the same state of the honoured author. But whoever decides to influence my very open professors and make me fail in my exams, also please read this response by nirmukta to one of his articles, to realize that I'm not the only person who feels like there's stone in the rice, waiting to be bitten. Ah! What an interesting title and how easy a way to grab the attention of a medical student tired of reading pharmacology.Within minutes of starting to read this book, I could smell honest but blind religiosity.With all due respect to the degrees the author possesses, this book isn't worth buying. But you should definitely read it once, to understand the workings of a conspiracy theorist's mind.
If you read with a truly open mind, you will be able to ignore the blatant errors of facts or practicality and focus on the drive home message, whi…

Why "Regulations" Are Often Not Helpful Solutions

The other day I saw an impassioned plea from a doctor asking associations to "regulate the profession". The reason they cited was that healthcare is turning commercial and often this goes against the best interest of the patient.

One of the many things I learned in National Law School listening to Prof Nandimath and others is that "regulations" come with their own set of problems.

Let us look at it more closely.

First, what is the problem we are trying to solve? The healthcare system in our country (many other countries too, perhaps) have huge flaws in it that lead to suffering and poor quality of care for the end user (the patient). Medical training is focused on the wrong parameters (recent change of UG curriculum to a competency based curriculum is proof of this). Distribution of healthcare providers is disproportionately concentrated in urban areas. Healthcare is episodic. Government policies are weakening public health system. (Public health system, even o…

Pathology Paper 1 Final exam RS2, RS3 2013 RGUHS 2nd year

An easy one

What to Make of Itolizumab?

It is the worst of times. Science is suffering an identity crisis. The world is in dire need of science. Science isn't used to being rushed. "It is a giant and slow churn", said a friend once, "and spews a breakthrough once in a while". Is it possible to make the process faster? That's what everyone is wondering. And praying. And waiting, eagerly. Science isn't used to getting this attention.
"Coronil is 100% effective", said Patanjali folks. "Favipiravir is 88% effective", said Glenmark folks. How to know the truth? Seeking truth has never been easy. Never has it been easy for journalists, scientists, or the common person. In some sciences there are multiple truths. Is medicine one of those sciences? Can there be a single truth in medicine?
I won't use words like epistemology and ontology in this post. (Because I still can't remember which is which). But the question is essentially two:
1. Is there a single truth? 2. Is there a…