How does administering PRN medications work?

Mike R, ADN, BSN, RN · Oct 21, 2010

Does that mean that the patient gets the medication only every two hours if needed.

^ This. Say I have a headache. I have a PRN order for Tylenol 80mg Tab PRN Q2hrs. I can get my Tylenol now at 1000 and if I still have it in two hours I can get it again at 12 and again at 1400 if need be. If I had it 'round the clock it would still be well under 4grams total. Though as a nurse, it's your call as to assess whether you have contraindicating s/e or overdosing and whether or not to hold meds.

elkpark · Oct 21, 2010

^ This. Say I have a headache. I have a PRN order for Tylenol 80mg Tab PRN Q2hrs. I can get my Tylenol now at 1000 and if I still have it in two hours I can get it again at 12 and again at 1400 if need be.

Or you could have it at 10:00, be fine at 12:00, but want it again at 1:35 and get it. It doesn't have to be given only at the two hour point -- prns are given whenever the the client wants/needs them (at the dosage specified in the order), but not closer together than the specified time range (q 2h, q 4 hr, whatever). So, in this case, if the client had Tylenol at 10:00 and 1:35, then the next earliest time s/he would be able to have it would be 3:45 (any time after 3:45).

Usually, if there is a maximum safe dosage, that is either specified in the original order ("q 4 hrs prn (whatever), up to a max of 12 mg/24 hrs") or pharmacy flags it with a recommended maximum. But, as Mike R notes, we always use our own nursing judgment, also.

Mike R, ADN, BSN, RN · Oct 21, 2010

Ok ya you explained it better :)

swansonplace · Oct 21, 2010

Thank you. It is clear that I would give the medication for example every two hours, and if they decline at the two hour mark, but want it later, I would give them the medication using the time as the new start time for the two hour requirment.

:heartbeat

elkpark · Oct 21, 2010

Thank you. It is clear that I would give the medication for example every two hours, and if they decline at the two hour mark, but want it later, I would give them the medication using the time as the new start time for the two hour requirment.
:heartbeat

You don't even necessarily offer it every two hours (or however frequently it's ordered) -- it's more a matter of waiting until the client asks for the medication or complains of something (for which s/he has a prn medication ordered).

decembergrad2011, BSN, RN · Oct 21, 2010

I wouldn't wait for the client to ask for the meds, but that's just me. Around the clock medication keeps pain better under control, and the majority of pain medication prescriptions are PRN. Pain should be part of your morning assessment when you first walk into the room. A simple, "Do you have any pain?" will suffice for the patients that you don't believe are in pain just to make sure. If they do have pain, rate it on a scale from 1-10 and document. This is important because when you reassess pain, you can ask them to rate it again and compare if the medication is controlling pain or not.

How I normally do it: I would let the patient know that they have the prescription available when they complain of pain, and then reassess their pain 30 minutes after giving the med. Around the time when they would be able to get the medication again, reassess their pain as well. After administering a dose, letting them know that they won't be able to get another dose until whatever time, whether that's 2 or 6 hours from now, is a good idea because it lets them know upfront that the order is to be spaced out X amount of hours rather than you just being a mean person.

(This idea works with antiemetics (meds for nausea/vomiting) as well, except that you assess for nausea rather than pain.)

In general, narcotics are going to be given with higher pain scale ratings and can be given less frequently, whereas analgesics (Tylenol, etc) can be given more frequently and can control smaller pain scale ratings. Most times I have encountered patients experiencing breakthrough pain with their narcotics, and the analgesics can be administered during the time when the narcotics are not available and the patient is waiting on the next dose.

Moral of the story? Assess, intervene, assess, intervene, ASSESS.

Personally I haven't encountered any PRN's that aren't for pain or GI issues (nausea/vomiting/diarrhea/constipation) aside from a nasal spray. I think there are probably more out there, but the majority of the time, PRN's are going to fall into the categories of pain or some type of GI distress.

elkpark · Oct 21, 2010

I wouldn't wait for the client to ask for the meds, but that's just me. Around the clock medication keeps pain better under control, and the majority of pain medication prescriptions are PRN. Pain should be part of your morning assessment when you first walk into the room. A simple, "Do you have any pain?" will suffice for the patients that you don't believe are in pain just to make sure. If they do have pain, rate it on a scale from 1-10 and document. This is important because when you reassess pain, you can ask them to rate it again and compare if the medication is controlling pain or not.
How I normally do it: I would let the patient know that they have the prescription available when they complain of pain, and then reassess their pain 30 minutes after giving the med. Around the time when they would be able to get the medication again, reassess their pain as well. After administering a dose, letting them know that they won't be able to get another dose until whatever time, whether that's 2 or 6 hours from now, is a good idea because it lets them know upfront that the order is to be spaced out X amount of hours rather than you just being a mean person.
(This idea works with antiemetics (meds for nausea/vomiting) as well, except that you assess for nausea rather than pain.)
In general, narcotics are going to be given with higher pain scale ratings and can be given less frequently, whereas analgesics (Tylenol, etc) can be given more frequently and can control smaller pain scale ratings. Most times I have encountered patients experiencing breakthrough pain with their narcotics, and the analgesics can be administered during the time when the narcotics are not available and the patient is waiting on the next dose.
Moral of the story? Assess, intervene, assess, intervene, ASSESS.
Personally I haven't encountered any PRN's that aren't for pain or GI issues (nausea/vomiting/diarrhea/constipation) aside from a nasal spray. I think there are probably more out there, but the majority of the time, PRN's are going to fall into the categories of pain or some type of GI distress.

I agree with you about pain meds.

pippylockstocking · Oct 21, 2010

There are PRN medications for lots of overthings. There are those for pain, as mentioned already, GI upset, as mentioned already... there is also Skin treatments, and Cardiac meds, Anti-anxiety, Sedatives, etc.

You always want to check what the parameters are with a PRN med. You need to follow those stricktly. The parameters should be specific. For example, old ways of writing pain meds used to be every 4-6 hours. Now JCAHO says it has be to more specific, either every 4 hours, or every 6 hours, but not a range.

This is how orders should be written:

PRN Tylenol 650 mg every 4 hours as needed for fever, headache, or pain.

PRN Ambien 5 mg at Bedtime as needed for Sleep.

PRN Ativan 10 mg every 8 hours as needed for anxiety.

So lets say you gave Ativan at 12 noon. That means the patient can not have it again until 8 pm. Now lets say the patient still has anxiety, and they are asking for more medication. You need to call the doctor to ask for an increase in dose or increase in frequency of dosing. Or a new med all together.

kayty83 · Oct 23, 2010

Here's a follow up question. We get a lot of orders that say like Morphine 1-2mg q 2 hours. (Probably q 4 is more realistic but I'm using q 2 for this example). I know I can give 2 mg every 2 hours if needed. But could I alternatively give 1 mg every 1 hour? They would still be getting 2 mg q 2. If I had given 1mg at 9am, 1 mg at 1000, could I give 2 mg at 1100? I'm thinking not...I could either give 1mg at 1100, or wait until 1200 and give 2 mg. Is that right?

Now let me think about 1-2 mg q 4 hrs. I give 1 mg at 0900. Then let's say I give another 1 mg at 1000 d/t unrelieved pain (assuming that's allowed, per my original question). When could I then give the next dose if it 1mg? If it is 2mg? (I'm thinking I could give 1mg at 1300, or if I wanted to give 2mg I'd have to wait for 1400). Am I doing this right? Thanks!!

pippylockstocking · Oct 23, 2010

Hi Kay,

This is a great example. This is actually the point I was trying to make but sometimes I tend to go off on tangents without getting my point across. Ok so your example said Morphine 1-2 mg. Now at one time I know alot of orders were written in a range like this. But a couple years ago, I am pretty sure that JACHO or some administrative body, (I can't remember who, but it was probably JACHO) said that medication orders can not be written in a range. They said it needs to be written specifically, either Morphine 1 mg, or Morphine 2 mg, but not 1-2 mg. Know what I mean?

So if I remember this correctly, when you see an order like this, technically you are supposed to call and get it clarified. Now this may have changed as this was 2-3 years ago... maybe other nurses recall this new rule?

Now also in your question: using the example of Morphine 1-2 mg q 2 hours. As far as I know, No you can not give it q 1 hour. If you give the smaller dose of 1 mg, it still must be q 2 hours, and not q 1 hour. You can not change the frequency of the dosing. The only part you can change is the dose. You either give 1 mg, or 2 mg, every 2 hours.

But again, as I stated initially, if you see a order written this way, you should call to clarify it because of new JACHO rules.

decembergrad2011, BSN, RN · Nov 4, 2010

To answer your first question, no. That is not what that order is stating. Another way to read that order would be, "A dose of 1 or 2 mg may be given 2 hours after the previous dose." You can change the dose, but not the amount of time between doses.

Prescriptions written in that way aren't meant to be further spaced out. They exist for the nurse to use their clinical judgment in deciding how much a patient might need within defined limits. Let's say we have the order of "Percocet 1-2 tab PRN pain Q6." If a patient is complaining of a pain of 5/10, they may request only 1 tablet of Percocet rather than 2 tablets. If they were in pain of 9/10, they probably should get the higher dose. If you give them 1 tablet at 0900, you cannot give them more of the Percocet until 6 hours later at 1500 (or 3 pm). At that point you could give them another dose of 1 tablet, or give them a full 2 tablets, but you would not be able to give that dose until 6 hours after the previous one.

Orders like that, as far as I'm aware, are perfectly legitimate. Of course, you can always call the pharmacy for clarification if an order is unclear, and you should, but in this case it's not a mistake. It's just allowing some leeway in dosing. A small patient who has not taken much pain medication probably will not need the same dose as a larger patient who takes medication for chronic pain, for example. I think of those kinds of orders as being like SDR's (safe dose ranges) in peds, but for adults.