Different ways to administer medication

I’ve been chewing on the different ways you actually inject stuff with a syringe—you know, the whole intramuscular, subcutaneous, intravenous, and intradermal spectrum. I need someone to break down the specifics for me: what kind of angles are we talking about here, and where exactly does each one go? Just keep in mind that we're dealing with ampulated medications intended for first aid scenarios. I can't exactly show up to my clinical rotation totally clueless; I'd really like to make a decent impression instead of looking like a total amateur.

So, what kind of internship are you even doing where you're learning how to give IV injections? Honestly, your intro was a little bit all over the place... obviously medications come in ampules, I mean, what else would they be in?
Every single method tells you exactly how to handle the injection. You go IM straight into the muscle at a 90° angle, SC under the skin at about 45°, ID just under the surface at maybe 15 to 20°, and then there's IV right into the vein, which totally depends on which vein you're hitting, what needle you're using, and what the actual goal is...

And seriously, did nobody teaching you this stuff actually explain it? Or are you just out here playing "wannabe" nurse or something? Hmm... weird, really weird... 🙂

This is how they are administered intramuscularly.

Yeah... I guess I'm getting there... hehehhehehe...
I'm actually just starting my nursing internship, though this whole training program is a bit of a headache. It’s designed to qualify you as a Level 3 technician, which eventually opens the door to working in the ER. I’ve already knocked out a few preliminary courses, but back then, I wasn't even allowed to touch anyone with meds, let alone administer them. Once I wrap this up, though, I'll finally have that clearance. It's all part of a volunteer medical training initiative run by the Knights of Malta...
Anyway, thanks for the help. By the way, the internship is going pretty well so far... I've mastered IM injections and subcutaneous shots, but IVs are still giving me some anxiety. Honestly, I'm a little terrified of hitting a vein wrong or causing damage. I’m doing fine on the practice mannequins, but I haven't quite worked up the nerve to try it on a real person yet. And soon enough, we'll be moving on to cannulation...

PS... one more thing... which vein is generally the easiest to puncture? You know, the one where there's the least risk of messing things up...
Also, for intramuscular shots, should I be aiming for the deltoid or the thigh?

hm....

So, are you actually heading over to the States? I’m still trying to wrap my head around this "Level 3 hospital" thing you mentioned. Plus, I’m totally lost on how a group like the Maltese Knights—or honestly, any religious order—could even train medical staff who have already finished nursing school or some kind of vocational program, let alone be authorized to go around giving people injections... could you walk me through how that all works?

I’m pretty sure that happened overseas somewhere...

So, there’s this Maltese order that’s been operating out in places like Lourdes since the late nineties. They actually managed to get the green light from our Department of Health and stuff to train people starting at sixteen to work in medical roles. The catch? For now—at least until they push for more licenses—those trainees can only work within their own facilities. It all came down to a massive labor shortage over in Germany, apparently. Their system is tiered, too. You’ve got nursing assistants, then Level II nurses who finished vocational school, and finally Level I professionals who completed a two-year college program. Those Level I folks are the ones who eventually move up to head nurse or lead technician positions. Anyway, side note: I just burst a vein on a patient...

Alright, here’s my next question...
How am I supposed to convert something like 0.3 mg of atropine given IV into milliliters? I mean, it doesn't really matter if it's this specific drug or something else entirely... Is there a universal way to do this, or does the process change depending on what you're working with?

Honestly, there’s really no need to get caught up in those kinds of calculations. Every finished medication is already diluted in its own specific volume... for instance, you'll find atropine in 0.5 mg or 1 mg ampules... nobody ever tells you to grab "xx ml" of atropine, they just tell you to give 0.5 or 1 mg.

Take adrenaline, for example. I know 1ml equals 1mg... but if someone asks for 1mg, do I just hand over the whole vial? And if they want 0.5, do I give them half? Or is there already a pre-measured 0.5mg vial out there somewhere? It’s all so incredibly vague... especially when you're doing clinical rotations. The doctor turns to you and says, "Give me 0.5mg of atropine," and honestly, I usually just pass the task off to a colleague because my brain simply refuses to process it.

cosmicmaker30 said:take adrenaline, for example—I know 1ml equals 1mg... so if someone asks for 1mg, I’d just hand them the whole vial, but if they want 0.5, I’d give them half... unless there’s already a 0.5mg vial out there? It’s honestly such a mess when we're doing our clinical rotations... the doctor yells, "give me 0.5mg of atropine," and then I just pass the task off to my colleague because I can't wrap my head around it...

but honestly, it's not even that deep once you get the hang of it. If you need to dose 0.5mg of Atropine, you just grab a vial that's pre-measured at 0.5mg, pop it open, and use the whole thing... or, if you've got a 1mg vial, you just draw up the full amount into the syringe and then pull back until you have exactly 0.5mg left to give... it's simple enough....

With epinephrine, it’s always 1ml = 1mg... but you really have to watch your step because you're often diluting it to a 1:10 or 1:100 ratio... sometimes even 1:1000... So, when the doctor tells you, "administer 1 ml of 1:10 epinephrine," here's what you do:
- grab the vial and open it up
- take a 10 ml syringe and draw up the entire dose of epinephrine. That's our 1 ml, as we established.
- grab a bag of saline and draw another 9 ml of saline into that same syringe with the epinephrine.
- now you've got a 1:10 epinephrine solution, and you administer 1 ml from that syringe intravenously.

If you need to give 1 ml of 1:100 epinephrine, the process changes slightly:
- grab a fresh, empty 10 ml syringe and attach a needle to it
- hold that pre-prepared 1:10 epinephrine syringe in your other hand
- use the empty syringe and needle in one hand to aspirate 1 ml of the 1:10 epinephrine from the first syringe held in your other hand....
- then, add 9 ml of saline to bring the total volume back up to 10 ml... and boom, you've got 1:100 epinephrine ready to go.
- from that syringe containing the 1:100 dilution, you administer 1 ml of the medication.

The absolute golden rule when you're messing around with all these meds is to label your syringes immediately. Seriously, write exactly what it is on the side right away, because later on, heaven help you, you won't have any clue which syringe is which...

cosmicmaker30 said:yeah... I'm hitting rock bottom here... hehehhehehe...
I’m actually just heading out for my nursing clinicals... though this specific training track is a bit of a labyrinth. It qualifies you to be a Level 3 technician, which eventually opens the door to working in the ER. I’ve already knocked out a few preliminary courses, but back then, I wasn't even allowed to administer medication on my own. Once I wrap this up, however, I'll have that authority. This whole program is part of a voluntary medical training initiative run by the Knights of Malta...
Thanks for all the help, by the way—the clinical rotation is going great. I’ve mastered IM injections, but IVs are giving me some grief. Honestly, there's a bit of anxiety there... the fear of missing the mark or damaging a vein. I’m doing fine with the practice mannequins, but I haven't quite summoned the nerve to try it on a living patient yet. And soon enough, we'll be moving on to cannulation...

P.S... one more thing... which vein is generally the easiest to access? I mean, which one carries the least risk of complications or whatever...
And for intramuscular shots, should I be aiming for the deltoid or the thigh?

For IM injections, if it's the right side, you aim for the upper right quadrant of the glute; if it's the left, you go for the upper left, or the outer area. Basically, you divide the glute into four quadrants and aim for that upper, outer square.

cosmicmaker30 said:sooo... one more thing... which vein is actually the easiest to hit? Like, where's the least risk or whatever...

There isn't really a set rule for this since everyone's anatomy is just so different. Honestly, before you even think about sticking a needle in, you should get your Esmarch tourniquet ready and really, really feel around for the veins... I mean, don't just look at them, you have to palpate them. Don't trust your eyes too much when judging a vein. Over half the time, you won't even see the vein, but you can totally find it if you feel under the skin—you can sense the direction, how firm it is, how flexible it feels... you know, that little "springy" feeling under your fingertip. Just make sure the vein is straight for at least 2 or 3 cm so you aren't dealing with some bumpy spot that’s just going to pop the second you pierce the wall. It’s way better to spend ten minutes scouting the right spot than to poke blindly and then end up hunting for the vein with the needle afterward...
Usually, for drawing blood, the veins in the antecubital area (like the v. basilica or v. cubitalis) are the most convenient, but if you're doing a line, you'd ideally want to check the veins on the back of the hand first before moving up toward the elbow. Veins in the legs can work for both blood draws and lines too, though obviously not for patients who are up and walking around—but for someone bedridden, it's definitely an option. You're mostly looking at the veins on the foot or around the ankle...
In those really extreme situations, you might have to go with the jugular in the neck or the femoral vein in the groin area..

Scott Allen10 said:but there’s really nothing complex to figure out here. If you need to give 0.5 mg of Atropine and you have an ampule containing exactly 0.5 mg, you just pop it open and give the whole thing.... If you’ve got a 1 mg ampule instead, you still open it, draw up the full amount into the syringe, and then just pull back until you hit that 0.5 mark, leaving the rest in the barrel.... simple enough....

Now, Adrenaline is always 1ml = 1mg... but you have to be careful because in practice, it's frequently diluted to a 1:10 or 1:100 ratio.... sometimes even 1:1000. So, when a doctor tells you, "give 1 ml of 1:10 adrenaline," here is what you actually have to do:
- grab the ampule and crack it open
- take a 10 ml syringe and draw up the entire dose of adrenaline. That’s your 1 ml, as we established.
- grab a bag of saline and draw another 9 ml of saline into that same syringe with the adrenaline.
- now you’ve got a 1:10 adrenaline solution, and you administer 1 ml of that from the syringe intravenously.

If the order is for 1 ml of 1:100 adrenaline, the process changes:
- grab a fresh, empty 10 ml syringe and attach a needle
- hold your previously prepared 1:10 adrenaline syringe in your other hand
- use the empty syringe and needle to aspirate 1 ml of that 1:10 adrenaline from the first syringe into the second one....
- then top it off with 9 ml of saline so you're back at a total of 10 ml... and there you have it, a 1:100 adrenaline concentration.
- from that syringe, you administer 1 ml of the medication.

One thing I can't stress enough when you're messing around with all this pharmacology: label your syringes immediately. Write exactly what is in them right away, because lord knows you won't remember which is which five minutes later.

I get it... I hear you... thanks a lot... 🙏🙏🙏🙏🙏🙏👍

Scott Allen10 said:There aren't any set rules here. It’s a highly individual process. Basically, before you make a call on which vein to hit, you need to check their history and really, truly palpate them... I don't mean just looking at the vein, I mean feeling it. Don't rely on visual assessment for any single vein. Over 50% of veins aren't even visible, but they are easy to gauge once you feel them under the skin—their direction, hardness, flexibility... you can feel that "springiness" right under your fingertip. Make sure the vein is straight for at least 2 or 3 cm so you aren't dealing with some bumpy mess that's going to pop the second you perforate the wall. Better to spend ten minutes assessing the vein than to poke blindly and then go hunting for it with the needle...
Generally speaking, for blood draws, the veins in the antecubital region (like the v. basilica or v. cubitalis) are the easiest, whereas for a Brown cannula, you should start by checking the veins on the hand first, and only move up toward the antecubital area if those aren't viable. Leg veins can also work for both blood draws and Brown cannulas. Of course, not for patients who are mobile and walking around, but for bedridden patients, absolutely. You're mostly looking at the veins on the foot or around the ankle area...
In more extreme scenarios, you might have to use the v. jugularis in the neck or the v. femoralis in the inguinal region...

Yeah... yeah... I get it... so... what matters is feeling for the vein... the one that feels better under my fingers is the one I should go for... even if... I can see a different one clearly...

I could really use some help here... does anyone actually know which size of cable tray goes where?

cosmicmaker30 said:I need some help here... which catheter size is used for what...

What do you mean, "used for what"? It all comes down to whether you're inserting the line yourself or using a butterfly needle, and it depends entirely on the vein. If the vein is thin, you aren't going to force the green one—which is the thickest—into it; you’d go with blue, or maybe pink. The green is typically reserved for blood transfusions because the viscosity of the blood requires it. For standard IV fluids or administering medication through a butterfly needle, honestly, it doesn't matter much. Essentially, you make your call based on your assessment of the patient's vein length and quality, but when a transfusion is on the table, you grab the green one.

Blue is for those thin, fragile veins.

Pink is for average veins, though you can use it on thinner ones if they aren't prone to blowing.

Green is for blood transfusions, thick veins, or cases where the blue or pink lines might clog, preventing medication or fluids from flowing properly.

And just so you know, at Mayo Clinic, we usually defaulted to the green one because you never truly know if a patient is going to need blood or if their condition will suddenly deteriorate. You don't have the luxury of time to come back and poke them again, so you just go straight to the green one to be safe.

That was the standard protocol we followed at the hospital.

Oh, and I can't quite recall which is thicker between the pink and the blue. If the blue is larger, then pink would be the substitute for it. It's been a while since I practiced, so my memory regarding these color-coded sizes is a bit rusty.

Choosing which IV catheter to use is really down to the individual; you have to look at the patient's overall stability—basically, what kind of fluids or meds they need, how much, and how fast they need them... plus, of course, you have to judge the actual quality of their veins.
The general rule of thumb I follow is to go with the largest gauge possible if the vein looks solid. Honestly, once someone is already getting poked, they usually stop caring about the specific needle size; whether it’s a 20G or a 16G, it’s all pretty much the same level of discomfort to them.

The green ones (18G) aren't actually the thickest out there, and while they get the job done most of the time, surgeons and anesthesiologists usually consider them right on the edge of being acceptable. They can also make blood transfusions a bit of a struggle. That's why we usually aim for the gray ones (16G) as our go-to. They’re sturdy enough that they won't kink or collapse in the vein, and the lumen is wide enough to handle high flow rates for both infusions and blood products. Every once in a while, if we can find a good spot, we might grab an orange one (14G) or even a white one (12G)... but those are basically heavy-duty tools we don't need unless things get intense.

As for the pink (20G) and blue (22G) catheters, they aren't necessarily "bad," but they should really only be used if the patient's veins just aren't big or strong enough to handle anything larger. You'll see these sizes used routinely in pediatrics, whereas in the NICU, they almost always have to stick with the yellow ones (24G).

You might still see a pink catheter (20G) being used for intra-arterial lines—usually in the radial artery when we need to monitor arterial blood pressure—but that’s a whole different conversation...

So, when you're looking at transfusions or heavy IV fluids, you really want to go big—ideally an 18G or maybe even a 16G, assuming the patient's veins can actually handle it without collapsing. But here’s what I was wondering: can you get away with using a 20G for an infusion? I tried using one the other day, and the doctor absolutely lost his mind. He started yelling at me about how I messed up, lecturing me on why it "had" to be an 18G and all that nonsense. I tried explaining that we just didn't have those larger sizes in stock at the moment, but he just snapped back that I shouldn't have used anything at all if I couldn't do it right. I just stood there kind of staring blankly... I mean... the fluid was flowing just fine, so I don't see what the big deal was.

Honestly, if you're doing transfusions or heavy fluids, you really want a larger gauge needle—something bigger than a standard 20G will move way faster, which is huge when things get intense. I bet the guy was yelling because if you need to run two IV lines at once, toss in some meds, and maybe even blood later on, you’ve got to use those multi-port connectors... trying to push all that through a tiny 20G is a total nightmare, it's painfully slow. Plus, those 20Gs are pretty short, maybe an inch or so, so if you're dealing with a bigger patient, it's way too easy to miss the vein entirely.
But look, if we're just talking about basic saline and maybe a couple of quick meds while the patient is stable and not heading into surgery or anything crazy... then that doctor was definitely being a bit of a smart-ass.