Applied Pharmacology 5, Theraputic Index

Therapeutic index is a measure of how safe a drug is, comparing the effective dose with the toxic dose.
Notes
The therapeutic index (TI) (also called therapeutic ratio) is a comparison of the dose of a drug that causes the therapeutic effect to the amount that causes toxicity. This describes the margin of safety, accounting for the effective dose, toxic dose and even potential lethal dose. The related terms therapeutic window or safety window refer to a range of doses which optimize between efficacy and toxicity. This is always where we aim to be.
High (wide) TI is good for good safety profile, drug has low toxicity
Low (narrow) TI is more risky (NTI drugs, narrow therapeutic index), drug more toxic
TD (toxic dose)
TI = -----
ED (effective dose)
TD50 (toxic dose)
TI = -----
ED50 (effective dose)
Lethal dose
Toxicity effects
Adverse response threshold
Therapeutic window / range
Duration of action
Sub therapeutic range
Desired response threshold
Eg, anticoagulants, hypotensives, hypoglycaemics, analgesics, diuretics,
Low (narrow) Therapeutic Index drugs
Digoxin 2:1
Paracetamol (acetaminophen) 7 gram fatal dose
Lithium - nephrotoxicity, ataxia, discordination
Warfarin -
Gentamycin - nephrotoxic, auditory nerve damage - ototoxicity
Vancomycin - nephro
Phenytoin, fast uncontrolled eye movements, dizzy confused, poor coordination, slured speech
Antidepressants, tricyclics
Insulin,
AZT,
High (wide) TI drugs
NSAIDs
Benzodiazepines
Most antibiotics
Furosemide
SSRIs
Does not include any synergistic effects, e.g. diazepam and alcohol or diazepam and morphine, aspirin and warfarin, pharmacokinetic, pharmacodynamics effects, eg. Furosemide and ACEIs (oprils)

[@Summertimeangel]

Thanks for taking the time to teach us Dr. Campbell :)

[@paulaandeabeldia1352]

Thank you Doctor. You are a born clinician and educator. 🎉

[@emmaj4121]

Dr Campbell you are amazing. Your videos are so helpful- thank you for taking the time to create them

[@shawndrearay2783]

This video really helped me understand the Therapeutic index! Thank you

[@nadiaaref4627]

Nerver could understand the whole idea about every subject I watch as I did with your way of illustration

[@SadamKhan-nn4vy]

Sir i am very happy to be with u on youtube. but it would be better to make playlist for particular medical science so that one can listen lectures not in vague manner

[@navdeepkaur8957]

Thank you so much sir for the information you provide. Your tutorials always help me making the concepts more clear.Please keep uploading this valuable information.Thanks:)

[@DUKWIEDUKWIE]

Great teaching thanks so much Dr

[@Tunir007]

Hello doctor! excellent video as always! i have one request though, could the person who manages this youtube channel please sometime take the time to categorise and group the several videos in the channel into various playlists based on the topics? there are sooo many videos over here and it would be extremely helpful if we could find a playlist as study accordingly of whatever topic may be in mind. thank you :D

[@Campbellteaching]

Good idea D, John

[@butaayijohn5335]

Thank you for the good work

[@anthonyfantasia3360]

Question for the doctor I can't figure out. How come in an aberrantly conducted PAC the QRS is wide? I've read it's due to the left bundle branch conducting the signal faster than the right bundle branch because they have slightly staggered relative refractory periods. Apparently this is what causes the abnormal conduction through the ventricles. What do you think?

[@anthonyfantasia3360]

Also (if the above is true), why would the left bundle branch be in a later stage of its respective refractory period compared to the right?

[@Campbellteaching]

If the complex is wider, this relates to more time. I think a PAC has an abnormal electrical ectopic focus, this means the conduction will not follow the physiological pathways through the atria, and so slow things down.

[@dianasalazar4488]

THANK YOU!! I was so confused when my teacher just breezed right over this on a power point. I'm a visual learner and this helps so much.

[@islamkhairul713]

excellent!! TI is easily explained

[@MrRaghavhegde]

Therapeutic Window/Therapeutic Index is nothing but MEC/MSC . the area between minimum effective concentration to the maximum safe concentration(minimum Toxic concentration) is called therapeutic index. The drug shows desired therapeutic effect until it lies between therapeutic window. which can only determined by conducting Therapeutic drug monitoring.where we can establish therapeutic ranges. Objective of Therapeutic Index: To derive best therapeutic outcome with least possible side effects/ Adverse effects.

[@timekiller8403]

Thanks bro.I was looking this kind of easy definition of T/I

[@Tumukundek]

Dr Campbell, thank you so very much, you are magical

[@ilaydamahmutoglu5942]

thank you sir, you are the best!

[@newday8159]

Thank you do more of these thank 🙏💖🙏

[@zabf8732]

Absolutely brilliant thank you

[@savitact7960]

thankyou sir very well explained

[@rheaflorpabriga9131]

thank you so much dr.,

[@manojbaskaran2853]

Very interesting topic actually #

[@md.sharifulislamswapon2685]

Very good explanation,,,,, tnx a lot,,

[@newday8159]

I keep thinking about this in terms of supplements and vitamins and no drugs.

[@fenisc]

pick over the trough?

[@umerulislam]

Thanks sir !

[@junczhang]

thanks

[@medicallectures9991]

The best teacher

[@rayconnel6026]

Very helpful

[@skincentives4377]

Sir, Is there any chance you could make a pharmacology video about drugs for nurses? 😊 you explain everything soo well...

[@Campbellteaching]

check out the series on applied pharmacology

[@Campbellteaching]

kzbin.info/www/bejne/iZybaYeubd1jpqM

[@skincentives4377]

Thank you soo much !!@@Campbellteaching

[@amanuelhussen191]

10q more explanation