I don’t usually comment on videos, but I HAD to come here and thank you for this one. This is a silly concept that I have been struggling with a lot for years and I finally understood it! Thank you very much for your time and effort!
I got into med school in 2015....and each year since then it's a ritual to see to video as I keep coming across volume of distribution again again....and this video makes me explain the concept so easily...thanks
To be sure I understood correctly: It is so much lost via this movement of the particles that I would have needed 50L of blood in order to indeed have my 10mg in the blood? Best video concerning this issue on UA-cam indeed!
Great video but I'm fairly sure that the concentration of drug in plasma includes that which is plasma protein-bound. Increased strength of drug binding to plasma proteins decreases Vd, and increased strength of binding to tissue components increases Vd.
I the video is wrong! Only one person on this discussion who noted the problem with the explanation. Warfarin is 99% bound and has a low Volume of distribution (of 8 Litres). By Bentley's explanation it should have a very high Volume of distribution as the free concentration is very small. If you take another drug which displaces the active drug under consideration - you will increase the free fraction. According to Michael Bentley this should decrease the volume of distribution as you have a larger denominator, but in reality you INCREASE the volume of distribution because more molecules are now free to exit the intravascular space (partitioning along their lipid solubility and tissue affinity propensity) and thus the Total intravascular drug concentration will DECREASE and the Volume of distribution (Dose / Total plasma concentration) INCREASES! The video is nevertheless extremely useful as it helps to conceptualize the molecules and how they move. Show less REPLY
Thank u very much.. I hava a doubt sir.. why the bound drugs with plasma proteins are not considered as they are also in the same fluid. On the other hand i also know that the plasma and blood is sperate in the other sense, but we have to know the volume of distribution where we consider whole body fluid including plasma.. Plz aware me about sir...
Its very helpful.. i use to think that after all duration of my studies i will end up with no understanding of Vd but really thanks to u sir 4 this illustration :)
Thank you sir,only one issue,I thought the drug that binds to plasma proteins is still in the vascular compartment and hence would mean high protein binding would lead to high plasma drug conc. and hence low v.d and not the opposite...thanks in advance
No, high protein binding means the drugs are binded to the plasma proteins (mainly) right? But these drugs that are existing in this form does not have any pharmacological action, meaning useless. The only significance of protein binding is that it acts as a reservoir to increase the duration of action of a drug and prevent toxicity. Because again, only free form of a drug which is in the blood volume can have either therapeutic effect or toxicity to a patient.
so what's the use of the volume distribution clinically if it have all these variant effecting factors and we also need to wait for the drug to be distributed through the compartments? Good explaining method thanks.
Hi, aren't plasma-protein-bound drugs part of the "plasma concentration of drug"? so a highly-protein-bound drug would have lower Vd (because of the larger denominator)? Not as what you said in the video? But thank you for the video - it really helps me with conceptualizing Vd regardless! Hope you can clarify the point about protein-bound drug, though. Thank you so so much again!!!
+Hikari Elf You are correct about plasma vol vs.blood vol. BUT for the purpose of explaining the concept of Vd, the number (3L vs. 5L) is not as important as the concept itself.
Spent hours trying to figure this and this video cleared it up in 6 and a half mins. THANK YOU!!
He is a saint indeed.
I don’t usually comment on videos, but I HAD to come here and thank you for this one. This is a silly concept that I have been struggling with a lot for years and I finally understood it! Thank you very much for your time and effort!
Best explanation I've found for this, cheers
I second that
Thank you very much
Thanks so much. I couldn't figure it out in class, but you made it clearer. God bless you, sir!
I got into med school in 2015....and each year since then it's a ritual to see to video as I keep coming across volume of distribution again again....and this video makes me explain the concept so easily...thanks
Literally the best video on this topic, got the concept within the first 3 minutes, can't thank you enough!!!!!!!!!!!
To be sure I understood correctly: It is so much lost via this movement of the particles that I would have needed 50L of blood in order to indeed have my 10mg in the blood?
Best video concerning this issue on UA-cam indeed!
This is exactly my thoughts put into perfect words, hope the concept is correct :D
@@zenzenzense1562 It is :-)
Your video def helped to enhance my comprehension of volume of distribution. Thank you Sir!
Very helpful for those who are paying attention to having volume of distribution being greater than 42L = TBW which doesn't make any sense. Awesome!
Thank you for explaining in 6 mins what my facilitator failed to do in a two hour lecture
God Bless you man ... this explanation is mind blowing thx very much sir.
So i think the culculation is wrong. Because u are not considering the plasma bound proteins.
I've been looking all over for a good explanation and you nailed it sir! Good job
Thank you!! med school never explained this so well!
Great video but I'm fairly sure that the concentration of drug in plasma includes that which is plasma protein-bound. Increased strength of drug binding to plasma proteins decreases Vd, and increased strength of binding to tissue components increases Vd.
I the video is wrong! Only one person on this discussion who noted the problem with the explanation.
Warfarin is 99% bound and has a low Volume of distribution (of 8 Litres). By Bentley's explanation it should have a very high Volume of distribution as the free concentration is very small.
If you take another drug which displaces the active drug under consideration - you will increase the free fraction. According to Michael Bentley this should decrease the volume of distribution as you have a larger denominator, but in reality you INCREASE the volume of distribution because more molecules are now free to exit the intravascular space (partitioning along their lipid solubility and tissue affinity propensity) and thus the Total intravascular drug concentration will DECREASE and the Volume of distribution (Dose / Total plasma concentration) INCREASES!
The video is nevertheless extremely useful as it helps to conceptualize the molecules and how they move.
Show less
REPLY
I was struggling understanding the concept of aVd
and this have helped me a lot.
THANKS
:)
What an amazing explanation.....THANK YOU!
Really amazing video ,go on 👏👏👏👏
Kudos Mr Bentley. Now I understand
Thank u very much.. I hava a doubt sir.. why the bound drugs with plasma proteins are not considered as they are also in the same fluid. On the other hand i also know that the plasma and blood is sperate in the other sense, but we have to know the volume of distribution where we consider whole body fluid including plasma.. Plz aware me about sir...
Its very helpful.. i use to think that after all duration of my studies i will end up with no understanding of Vd but really thanks to u sir 4 this illustration :)
Thank you sir,only one issue,I thought the drug that binds to plasma proteins is still in the vascular compartment and hence would mean high protein binding would lead to high plasma drug conc. and hence low v.d and not the opposite...thanks in advance
What r u saying mate
I didn't understand
Can u plz explain me
No, high protein binding means the drugs are binded to the plasma proteins (mainly) right? But these drugs that are existing in this form does not have any pharmacological action, meaning useless. The only significance of protein binding is that it acts as a reservoir to increase the duration of action of a drug and prevent toxicity. Because again, only free form of a drug which is in the blood volume can have either therapeutic effect or toxicity to a patient.
So a drug bound to plasma proteins does NOT contribute to the concentration measured in the vascular compartment?
No
Sorry, what do you mean by "no"? Regarding my statement "no", or does it not contribute?
Thank you, you explained it succinctly but thoroughly.
A very good video that helped me get my mind around this! thank you
Best explanation on this topic.Thanks a lot!
Thanks a lot for the video!! It helped me really to understand this apparently confusion theory..
so what's the use of the volume distribution clinically if it have all these variant effecting factors and we also need to wait for the drug to be distributed through the compartments?
Good explaining method thanks.
Yes, I finally found the video to link my understanding after many attempts at other ones.
This video helped me calculating the volume of concentration. Thanks a lot
Wow sir...thanks a ton...u made it look so easy to apprehend..!
IS the Vd is A CONSTANT where its value are the same all the times?
Thanks for the video it was very well explained 👍
at 4:20 you say the drug is not lipophillic its hydrophobic. If its hydrophobic it can cross the membrane. lipophillic and hydrophobic is the same.
Thank you!!
btw im pretty sure you meant Lipophobic 4:28
If he meant lipophobic then why would the drug want to attach itself to fat? lol
He says its hydrophobic, which it wants to pass the membrane. He shows the opposite in the example. the drug is hydrophillic/lipophobic
Very helpful, thankyou!
This was very helpful! Thank you so much.
Amazing video thank you sir but I have a question
If the drug has high affinity on albumin and all 10 molecules bind on it
So we need 10 litres??!
Hi, aren't plasma-protein-bound drugs part of the "plasma concentration of drug"? so a highly-protein-bound drug would have lower Vd (because of the larger denominator)? Not as what you said in the video?
But thank you for the video - it really helps me with conceptualizing Vd regardless! Hope you can clarify the point about protein-bound drug, though. Thank you so so much again!!!
Wonderfully explained sir
best explanation,amaizing
VERY helpful! Much appreciated!
would an increase in Vd lead to high potency or low potency of the drug?
Mr Bentley, If I remember correctly, a drug being lipophilic makes it also hydrophobic, did you mean to say lipophobic?
+Abdo hashem At 4:28 he probably meant hydrophilic (which equals to lipophobic - but the term hydrophilic is more commonly used than lipophobic)
+Abdo hashem yeah i caught that too - lipophobic=hydrophilic and vis-versa. I'm sure he meant to either say lipophobic or hydrophilic
thanks very much ! this made it so much easier
Very helpful 👍
Thank you so much, this video was very helpful.
Nice explanation sir
Yes it was very helpful. Thank you.
Thank you sooo much ... you've helped me a lot.
How does Vd increase in acute illness?
GREAT EXPLANATION!!
Nicely explained!!. thanks a lot
2 years into medical school and I finally got it. Thanks!
would u please explain pharmakokinetics models analysis ??
Clear explanation! Thankss!
Thank you that was really helpful 💪🏼
Excellent by far.
Thank you, thank you, thank you!!!
Nice explanation, thanks
great explanation.. thank u
Amazing video thank you!
Thank u duude
Very helpful
Thanku sir...it's awesome
But what is practical use of Vd?
Thanks tout vert much for this helpfull vidéo
thanks a lot. finally understand Vd!
You are a saint
Thnk u you made my day 😊
Nicely explained :D
Thank you!!
thank you legend
Thanks!!! finaly I understand it! thx
GREAT
Good
very helpful
Thaaaaank U
Sir, Vd= dose / [plasma] ... Isn't plasma volume = 3L not 5L ? 5L is 'blood' volume not plasma volume
Hikari Elf so whats is the final answer...? should we multiply by 5 or 3 ?
@Michael Bentley
+Hikari Elf
You are correct about plasma vol vs.blood vol. BUT for the purpose of explaining the concept of Vd, the number (3L vs. 5L) is not as important as the concept itself.
thanks a lot!
Rất tuyệt
thank u very much
❤️
thank you
Thank u very much
leave a like =']
Poor voice quality
thank you