No, I already have a B.S. degree and a Pharm.D. I also am board certified by the American College of Clinical Pharmacy (ACCP) in oncology and pharmacotherapy. I watch to stay updated in pharmacy.
Hey sir may i know from where u belongs because am studying pharmD am indian so i have no idea about how the scenario of pharmD's graduates outside india so it will be great pleasure if you share some information. Thank you.
Loved this video. Watched it quite a few times and picked up so much valuable information from it. Dunno who the presenter is, but he made it easy to understand and was easy to follow. Big thanks!
your formula you gave for maintenance dose at 21:01 seems like the what we would use to calculate dosing rate which is different from maintenance dose; maintenance dose = (dosing rate x dosing interval)/ bioavailability
Hello guys is there anyone who can provide an explanation. I understand the 4 basics; absorption, distribution, metabolism and elimination I just don't understand how and where they occur. For example, when the drug is absorbed orally and is metabolised in the liver, where does the distribution stage come into effect. When does the drug enter the blood system? Cheers!
The drug passes through the intestinal wall into the portal circulation, then through the liver, then into the inferior vena cava, then to the heart, and then to the rest of the body. Some drugs pass from the intestine into the lymphatic vessels, and then into the heart without passing through the liver.
How do you know what the specific clearances are for a particular drug? Also how do you know the different variables he discussed, like the volume of distribution, the lipid solubility, etc. pardon my ignorance I am a nursing student new to pharmacology and trying to wrap my head around it a bit before next quarter starts in 2 weeks. Are all of the given variables given on every drug label, or what?
Hey, thank you for these vids - you're a life saver! Quick question: (I don't know if you reply to comments but a response would be much appreciated.) You said that phenytoin was zero order but I vaguely remember something about it being second order (? - is that even a thing?) after a certain amout of time and it's a really dodgey one and one to watch out for because there's risk of accumulation because of rate of change of elimination - could someone explain this please?
Phenytoin is considered to be a "mixed order" (aka second order, aka Michaelis-Menton modeled) drug, meaning that it behaves as a zero order drug at high concentrations (this is the way it's normally clinically administered) and behaves as a first order drug at low concentrations. Zero order drugs have a linear arithmetic dose-elimination curve, while first order drugs have a dose-elimination curve that is somewhat exponential-like. This means that first order drugs are eliminated from the body very quickly at first, and then at a progressively slower rate once the drug concentration approaches lower numbers (e.g., if elimination half life is 1hr, then after 1hr, only 50% drug remains). However, for zero order drugs, since they have a linear constant rate of elimination (e.g, if elimination is 20% per 1hr, then after 1h, 80% drug remains, and after 2h, 60% drug remains), it takes zero order drugs LONGER to be eliminated from the body compared w/ first order drugs (most drugs used in clinical practice). Thus, there's an increased risk for zero order drugs (e.g., 80% remains after 1h) vs. first order drugs (e.g., 50% remains after 1h).
wow!! this video was perfect! Although one question... I have an exercise to solve and i have the time and concentrations so i designed on a linear paper and on a logarithmic paper the curve. There is one question that says to calculate the Ke and the Clearance but how can i calculate these when the only thing i know is the AUC???
first of all, thank you so very much!! Second of all, I don't know if you will read this or not, but the graph at the end for the zero order didn't make sense to me. We should have a nonlinear graph at high concentration. you showed it as a linear. and vice versa for the first order. did I understand it wrong or something?
thanks it helped a lot. just one question please. are all of the drugs go through these steps? i mean i have to write a piece on Pk of propranolol, so will it be the same steps or hypertension drugs have different absorption and elimination. regards
Good video but do not use if you are studying for a pharmacy PK exam. You need a video that shows you how to do the calculations step by step. This is not the one.
Half life for 1st order drugs remains constant, while for zero order drugs, half life changes depending on the particular rate of clearance for each specific drug.
Thank You! som much.. It was easy to understand and Remaining Exam preparation Job ! on me.. thanks for making it easy. WIsh you talked about Aread Under Curve, CMAX CMIN, HALF LIFE
If the half life of a drug is 5 hours, is that 5 hours from the time the drug is administered or 5 hours from the time it reaches it's peak concentration?
MC Ho Thanks. I'm still a little confused. By "in the system" do you mean when the first traces of the drug are detectable in the blood, or when all of the drug is in the blood? If a drug's peak concentration is 100 mcg/DL, and it reaches its peak concentration in 2 hours, and its half life is 5 hours, what will its concentration be at one half life and at two half lifes?
***** The simple answer would be when the first trace of drug enters the blood. As for the second question, as the definition of half life is the time elapsed for the plasma conc. of a drug to reach 50% of it's initial conc. (at t0), the conc. would be 50mcg/dL at first t1/2, and 25mcg/dL at 2nd t1/2 in the example. Not sure if that is the answer you are looking for. As you may know, the half life of a drug is dependent of a lot of factors (eg. route of drug administration(IV, inhalation, oral...), infusion rate, rate of metabolism, rate and volume of (re)distribution, rate of elimination...etc.)and is often time only obtainable by using computer simulation(eg. for multicompartment system) in form of a statistical distribution(different individual physiology). From what I understand, more applicable half life calculation would be in cases that more closely approximate single compartment system. Such as IV or inhalation drugs that have fast induction rate, with negligible time elapsed before reaching the peak conc., and minimal redistribution/tissue retention. I do not claim to be an expert in this topic. It would be interesting to hear opinions from the others.
Does the half life mean the drugs is inactive? It would seem that some things that are long treatments would start to get risky. If the average dose is 100mg per day and the half life is 18-22 hours, also the LD50 for...let's say 130lb(59kg) human is 140g. If you had to take this drug for 2-3 months then wouldn't you start getting into LD50 territory? Or would the drug possible be partially inactive since it is about to be excreted therefore lowering the risk of any possible lethal situations?
No, but you're on the right track. For first order drugs, which account for the majority of drugs used clinically, 5 x half life = steady state concentration of drug. At steady state, the drug is effectly inactive and will produce very little response, unless additional doses are added. You're correct that with drugs that have a narrow range between the lethal and effective doses (here, you provided 140mg = lethal dose & 100mg = effective dose) risk accumulating and being dangerous to patients. These drugs often do accumulate and cause undesired effects, which is why concentrations of chemotherapy treatment drugs and other long term treatment drugs are vigilantly monitored in patients.
Maybe an old video - but have been super struggling understanding the lectures around Pharmacology. This has helped tonnes! Thank you!
Thank you for watching, really appreciate the feedback!
No, I already have a B.S. degree and a Pharm.D. I also am board certified by the American College of Clinical Pharmacy (ACCP) in oncology and pharmacotherapy. I watch to stay updated in pharmacy.
do you have a video about pharmacokinetics calculation step by step, like u said before?
Yeah if u got such vdo pls drop the link below
Hey sir may i know from where u belongs because am studying pharmD am indian so i have no idea about how the scenario of pharmD's graduates outside india so it will be great pleasure if you share some information.
Thank you.
WELL DONE. BRILLIANT PRESENTATION (IN-DEPTH). THANK YOU SO MUCH.
Loved this video. Watched it quite a few times and picked up so much valuable information from it. Dunno who the presenter is, but he made it easy to understand and was easy to follow. Big thanks!
Use yellow marker please for visibility
This is awesome! I'm a PA student so this is a tiny bit more in depth than what we need to know but still complements my studies very well!!
thank you. you are awesome. why cant everyone teach like you? you made my life so much easier
I had a few complains about 10 minutes prior to its end but then you pretty much cleared most of my confusions in that remaining time.. thanks a lot
thank you so much! i'm in PA school and it is difficult to understand my pharm professor's lectures. this is great and easy to follow. thank you!
Welcome
This is brilliant
Enteral and parenteral are the two main methods of absorption. Enteral involves GI tract, parenteral includes every other method
that was awesome and i appreciate
Great teacher and great teaching, absolutely outstanding teaching Amen ❤🎉❤
u saved my life!please keep making videos!
Whats the screen he using
Thank you so much for this lecture.
Do you have a video on analgesics class?
thank you so much! Super helpful, you explained Vd so clearly, I was having a lot of troubles with it.
Great Explanation thank you WOW
This is amazing,been struggling with this for weeks!Thank you so much ,God bless you!
Nice to see it in a way in which beginners can understand and build! Thank you!!
Really good explanation about pharmacokinetics, good work!!
your formula you gave for maintenance dose at 21:01 seems like the what we would use to calculate dosing rate which is different from maintenance dose; maintenance dose = (dosing rate x dosing interval)/ bioavailability
Thank you professor I am very happy and satisfied when lecture
You helped my dad a lot
Transdermal and respiratory are parenteral way also. parenteral means "other than enteric way"
you r right. I think should be topical rather.
a lifesaver....
Thank you so much for making it clear and understandable..
its nice to see it in a different way! it has help me understand more and it is easier to understand using two perspective!
I'm a vet student and I thank you for this haha
Absolutely brilliant lecture! So helpful
THANKS ALOT ,NOW KATZUNG MAKES MORE SENSE
Really good and simple lecture of a tedious stuff. Thank you :)
This is very educative and simple to follow.
Hello guys is there anyone who can provide an explanation. I understand the 4 basics; absorption, distribution, metabolism and elimination I just don't understand how and where they occur. For example, when the drug is absorbed orally and is metabolised in the liver, where does the distribution stage come into effect. When does the drug enter the blood system? Cheers!
The drug passes through the intestinal wall into the portal circulation, then through the liver, then into the inferior vena cava, then to the heart, and then to the rest of the body. Some drugs pass from the intestine into the lymphatic vessels, and then into the heart without passing through the liver.
...so the correct answer should be the portal vein, right?
You are amazingly brilliant teacher, thank you so much.
well you made it very easy
but please can you connect half life to 1st and 2nd order kinetics? and explain?
Haryana aale 👍
How do you know what the specific clearances are for a particular drug? Also how do you know the different variables he discussed, like the volume of distribution, the lipid solubility, etc. pardon my ignorance I am a nursing student new to pharmacology and trying to wrap my head around it a bit before next quarter starts in 2 weeks. Are all of the given variables given on every drug label, or what?
20mins in. Need a break. Thanks for this :)
Great video for reviewing the basics
Hey, thank you for these vids - you're a life saver! Quick question: (I don't know if you reply to comments but a response would be much appreciated.) You said that phenytoin was zero order but I vaguely remember something about it being second order (? - is that even a thing?) after a certain amout of time and it's a really dodgey one and one to watch out for because there's risk of accumulation because of rate of change of elimination - could someone explain this please?
Phenytoin is considered to be a "mixed order" (aka second order, aka Michaelis-Menton modeled) drug, meaning that it behaves as a zero order drug at high concentrations (this is the way it's normally clinically administered) and behaves as a first order drug at low concentrations. Zero order drugs have a linear arithmetic dose-elimination curve, while first order drugs have a dose-elimination curve that is somewhat exponential-like. This means that first order drugs are eliminated from the body very quickly at first, and then at a progressively slower rate once the drug concentration approaches lower numbers (e.g., if elimination half life is 1hr, then after 1hr, only 50% drug remains). However, for zero order drugs, since they have a linear constant rate of elimination (e.g, if elimination is 20% per 1hr, then after 1h, 80% drug remains, and after 2h, 60% drug remains), it takes zero order drugs LONGER to be eliminated from the body compared w/ first order drugs (most drugs used in clinical practice). Thus, there's an increased risk for zero order drugs (e.g., 80% remains after 1h) vs. first order drugs (e.g., 50% remains after 1h).
Drug will also go in to liver after pumped by heart so is it metabolized at that time?
Great Job...excellent explanation and outstanding patience given.
WOW great Job thank you so much
Thank you for your generous feedback!
wow!! this video was perfect! Although one question... I have an exercise to solve and i have the time and concentrations so i designed on a linear paper and on a logarithmic paper the curve. There is one question that says to calculate the Ke and the Clearance but how can i calculate these when the only thing i know is the AUC???
I love these, THANK YOU!
but what is the difference between the terms clearance and elimination of the drug??
first of all, thank you so very much!!
Second of all, I don't know if you will read this or not, but the graph at the end for the zero order didn't make sense to me. We should have a nonlinear graph at high concentration. you showed it as a linear. and vice versa for the first order. did I understand it wrong or something?
Thanks for the comment! Zero order kinetics would be a linear graph, while first order would have a non linear graph. Sorry for the confusion!
Can you share liver architecture video
thanks it helped a lot.
just one question please. are all of the drugs go through these steps? i mean i have to write a piece on Pk of propranolol, so will it be the same steps or hypertension drugs have different absorption and elimination.
regards
Your voice is epic and hilarious all at the same time. Makes learning fun, thank you!!!
absolutely amazing,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
this is so helpeful,,i appreciate
Is extraction the same as first pass effect?
Buckal and sublingual routes are also enteral route of administration but they bypass G.I. then why has he said that enteral means drug go through GI.
Thank you very much for your video! It helps answer a lot of my questions. Highly appreciate your effort in preparing it!
Good video but do not use if you are studying for a pharmacy PK exam. You need a video that shows you how to do the calculations step by step. This is not the one.
u doing phrmcY?
Iam laughing my ass off here in the library .
"Simple right? NO CANT BE SIMPLE!"
Great video,many thanks
Where can I find online a good website that explain the drug actions ?
Ooommg amaaaaazing really really perfect thaaaanx alot
Wow..u jus made t so easy for me..thanx
is hepatic clearance the same as hepatic extraction?
CAN YOU SHARE EXAMPLE OF FIRST DRUG ELEMINATION?
excellent presentation, thanks!
Very very helpful…. Just asking, is the half life the same for both 1st order and 0 order reactions? I'm quite blur on that. Thx btw! :)
Half life for 1st order drugs remains constant, while for zero order drugs, half life changes depending on the particular rate of clearance for each specific drug.
Thank You! som much.. It was easy to understand and Remaining Exam preparation Job ! on me..
thanks for making it easy. WIsh you talked about Aread Under Curve, CMAX CMIN, HALF LIFE
Great lecture! :) Greetings, from a student in Norway.
Thank you very much! Had been very useful!
you left out 1st order kinetics formula, but the rest was good
What application you use write your tutorials ?
hey ur vedios r awsm.......did u make one on adrenocorticosteroids? i cudnt find it...if nt can u make one?
How about eye drops? Parenteral?
Topical route
Thank you.☺
great explanation
you are a great teacher!! So clear!
Excellent lecture
If the half life of a drug is 5 hours, is that 5 hours from the time the drug is administered or 5 hours from the time it reaches it's peak concentration?
From the time when the drug is in the system.
MC Ho
Thanks. I'm still a little confused. By "in the system" do you mean when the first traces of the drug are detectable in the blood, or when all of the drug is in the blood? If a drug's peak concentration is 100 mcg/DL, and it reaches its peak concentration in 2 hours, and its half life is 5 hours, what will its concentration be at one half life and at two half lifes?
***** The simple answer would be when the first trace of drug enters the blood. As for the second question, as the definition of half life is the time elapsed for the plasma conc. of a drug to reach 50% of it's initial conc. (at t0), the conc. would be 50mcg/dL at first t1/2, and 25mcg/dL at 2nd t1/2 in the example.
Not sure if that is the answer you are looking for. As you may know, the half life of a drug is dependent of a lot of factors (eg. route of drug administration(IV, inhalation, oral...), infusion rate, rate of metabolism, rate and volume of (re)distribution, rate of elimination...etc.)and is often time only obtainable by using computer simulation(eg. for multicompartment system) in form of a statistical distribution(different individual physiology).
From what I understand, more applicable half life calculation would be in cases that more closely approximate single compartment system. Such as IV or inhalation drugs that have fast induction rate, with negligible time elapsed before reaching the peak conc., and minimal redistribution/tissue retention.
I do not claim to be an expert in this topic. It would be interesting to hear opinions from the others.
Are the lungs too minor of an organ that plays a role in elimination?
yes the main organs for elimination are kidney and the liver.
Thanks
Great Video ! Thanks !
Great idea. thank you
Thank you for the video! Very helpful
thank you so much for this video....it was really helpful...
Does the half life mean the drugs is inactive? It would seem that some things that are long treatments would start to get risky. If the average dose is 100mg per day and the half life is 18-22 hours, also the LD50 for...let's say 130lb(59kg) human is 140g. If you had to take this drug for 2-3 months then wouldn't you start getting into LD50 territory? Or would the drug possible be partially inactive since it is about to be excreted therefore lowering the risk of any possible lethal situations?
No, but you're on the right track. For first order drugs, which account for the majority of drugs used clinically, 5 x half life = steady state concentration of drug. At steady state, the drug is effectly inactive and will produce very little response, unless additional doses are added. You're correct that with drugs that have a narrow range between the lethal and effective doses (here, you provided 140mg = lethal dose & 100mg = effective dose) risk accumulating and being dangerous to patients. These drugs often do accumulate and cause undesired effects, which is why concentrations of chemotherapy treatment drugs and other long term treatment drugs are vigilantly monitored in patients.
This vido is very useful , thank you but I want to know information about AUC and Cmax
That was fantastic!
you're a god
THANK YOU SO MUCH .
Really good.......
Many thanks!
انت بني ادم محترم❤️
Thank you this was really helpful
Great job, thanks
"made simple" but is 53 min long lol :P
THANKS
Thanks I needed this
nice one tnx
thanks a lot
this is lovely xx
❤
👏👏👏👏👏