Pharmacology Plasma donation & drug clearance

[Quasimoto]

I was donating plasma today and started thinking about the potential for this procedure to take drugs out of your bloodstream. Some basic googling says that this could potentially be a concern by raising blood clearance of certain drugs. I'm not on any vital medications or anything, and I assume it's not a big deal, but could this theoretically induce withdrawal quicker than usual?

How would that even work?

Would drugs that bind to proteins be pulled out more than drugs which don't bind to proteins so much? Are they filtered/caught by the machine and/or returned with your blood?

Fairly niche question, and I'm asking purely out of curiosity. I assume it will be a non-issue for me.

According to this: https://cdn.mdedge.com/files/s3fs-public/Document/September-2017/1105CP_Selvaraj_Beach.pdf

"During PP, solutes in plasma such as drugs can be removed, increasing drug clearance by 30%.2,3 PP affects both protein-bound and free drug concentrations. PP effectively clears drugs that are highly protein bound and have a small volume of distribution."

Just wondering if anyone else knows any more.

 

[rentedbythehour]

I was donating plasma today and started thinking about the potential for this procedure to take drugs out of your bloodstream. Some basic googling says that this could potentially be a concern by raising blood clearance of certain drugs. I'm not on any vital medications or anything, and I assume it's not a big deal, but could this theoretically induce withdrawal quicker than usual?

How would that even work?

Would drugs that bind to proteins be pulled out more than drugs which don't bind to proteins so much? Are they filtered/caught by the machine and/or returned with your blood?

Fairly niche question, and I'm asking purely out of curiosity. I assume it will be a non-issue for me.

According to this: https://cdn.mdedge.com/files/s3fs-public/Document/September-2017/1105CP_Selvaraj_Beach.pdf

"During PP, solutes in plasma such as drugs can be removed, increasing drug clearance by 30%.2,3 PP affects both protein-bound and free drug concentrations. PP effectively clears drugs that are highly protein bound and have a small volume of distribution."

Just wondering if anyone else knows any more.

Definitely curious about this as well.

 

[Skorpio]

I was donating plasma today and started thinking about the potential for this procedure to take drugs out of your bloodstream. Some basic googling says that this could potentially be a concern by raising blood clearance of certain drugs. I'm not on any vital medications or anything, and I assume it's not a big deal, but could this theoretically induce withdrawal quicker than usual?

How would that even work?

Would drugs that bind to proteins be pulled out more than drugs which don't bind to proteins so much? Are they filtered/caught by the machine and/or returned with your blood?

Fairly niche question, and I'm asking purely out of curiosity. I assume it will be a non-issue for me.

According to this: https://cdn.mdedge.com/files/s3fs-public/Document/September-2017/1105CP_Selvaraj_Beach.pdf

"During PP, solutes in plasma such as drugs can be removed, increasing drug clearance by 30%.2,3 PP affects both protein-bound and free drug concentrations. PP effectively clears drugs that are highly protein bound and have a small volume of distribution."

Just wondering if anyone else knows any more.

I’ve thought about this too (as well as bloodletting/donating blood and getting a transfusion to sober up).

The key in that bolded part of your post is the volume of distribution. That refers to the amount of drug which stays in your blood versus drug that resides in different organs..

I would expect some drugs to not clear very much at all. If a drug has a high volume of distribution, it will partition strongly to the brain or fat, replacing the drug in the blood will decrease levels at low rates.

However, frankly I’m not really sure how donating plasma works. My loose understanding is that you give blood, and it is centrifuged into layers, allowing your red blood cells to be returned, while keeping your platelets and plasma.

The plasma should have both aqueous and protein bound drugs in it as the main protein in blood, albumin is in plasma. Some drugs like warfarin are highly protein bound, and the main protein they are binding to is albumin.

A quick google search said that donating plasma can increase clearance of drugs by 30% (looks like the same source you found). Unfortunately it doesn’t go into detail of the specifics, but it seems to imply that protein bound drugs are preferentially cleared. this could simply be because a larger portion of a highly protein bound drug will be in the blood, as a drug dissolved in the water in blood would stay with the plasma rather than coming across in the red blood cell fraction that is given back to you. I would guess that the emphasis on protein bound drugs in that article is that drugs with lower protein binding have higher volumes of distribution, and more of them are elsewhere other than in your blood.

That being said, I do think one counter argument to significant quantities of drugs coming over in plasma is that i don’t hear about people getting high or having weird drug reactions when getting transfusions of plasma or other drugs. This could be due to some quality control process, or maybe dilution if plasma was mixed before being administered (though that sounds like a super bad idea due to the possible spread of disease). People with significant drug habits can get blood levels of drugs many times what a sober person would, so it should be possible for a sober person to be affected, even considering the small fraction of your total blood volume taken.

As usual, I feel like I am progressing in my ability to type “I don’t know,” in the largest amount of words possible.

 

[3DQSAR]

I can at least confirm that in the UK those prescribed medical marijuana cannot donate blood - and to the best of my knowledge, that's by far the MOST lipophilic recreational drug.

They refused to accept a donation from me because I am prescribed both oxycodone and clobazam. I don't abuse them or ever take them more than stated by my consultant BUT while the nurses were kind, they did say that someone who had suffered a major trauma might be especially sensitive to even small quantities of my medication and so were forced to politely decline. I was even offered the customary biscuit, cup of tea and sticker with 'I Gave Blood' which they asked me to wear as an ad for the ongoing campaign to get enough donations. I felt a total fraud.

Anyone injecting drugs is also prohibited from donating blood but I suspect that may be due to blood borne viruses and possibly other infections due to unsafe injecting practices.

FYI Air ambulances and more generally ambulances responding to major incidents where a lot serious trauma victims have been identified will both carry a doctor as well as an EMT. In these circumstances, doctors will transfuse whole blood where necessary.

As an aside, I note that many NATO countries are trialling the concept of 'warm banks;' i.e. every serviceman will have blood tests carried out to ensure their blood is usable and each one of them is essentially s walking blood bank. I've been witness to a situation where someone died who may have lived if those around them could have acted as such a 'warm bank'. That was a bad day.