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Drug Levels

Blood Concentration
Graph

Medication Level (Bioavailability)
vs. Time
(This page is not imtended
for small screens.)

by
Vaughn Aubuchon

When is the best time to take a medicine to maximize its effectiveness?

Many medicines, such as aspirin and clonidine, closely follow the time curves shown below. The peak occurs at about 1 1/2 hours after ingestion, and the medicine is mostly metabolized after about 8 hours.

At about one and one-half hours after ingestion, the greatest blood-thinning effect of aspirin will be realized. At about one and one-half hours after ingestion, the greatest blood-pressure lowering effect of clonidine (Catapres) will be realized. I have graphed the clonidine effectiveness by measuring my blood pressure over time. After about 8 hours, my blood pressure rises back up to the level where it was when I took the pill.

.

300

140

.
Blood Concentration Levels
vs. Time Chart

Blood Concentration Levels Over Time Graph
The standard dosing for clonidine
is typically a single dose daily.

WHEN should you take it?
Wouldn't it be better, to either,
---- 1) take a 1/3 dose 3 times a day? or,
---- 2) take a FULL dose 3 times a day?

One thing has become crystal clear to me.
The MEASURING TIME must always be
referenced to the INGESTION TIME, and half-life,
to have any meaning, at all.
Otherwise, you are just talking jibberish.

Data for the Above Chart

Times per Day
Doctor
Code - Latin
Hours
Period
Pro - Con.
Once

S.I.D. - semel in die

24

Largest ineffective period

Easiest dosing

Twice

B.I.D. - bis in die

12

Shorter ineffective period

Medium dosing

Three times

T.I.D. - ter in die

8

Shorter ineffective period

Harder dosing

Four times

Q.I.D. - quater in die

6

Shortest ineffective period

Hardest dosing

.
Pharmacokinetics Factors that determine blood levels (bioavailability) over time include -
- The Volume of Distribution (Vd) = Drug amount / Blood concentration
- The Clearance (Cl) of a drug = Drug Amount / Time
- The Elimination constant (kel)
- Fat solubility vs. Water solubility
.

-

100

130

50

200 - 600

120



.
Experiment Design
Varying Two BP Medications

There is great variation in BP readings, especially if the ingestion time and measurement time are inconsistent. Here, I attempt to discern the BP effects of altering drug ingestion times, using two different protocols.

Ex. #1
(after 1 week)

6 AM
12 PM
6 PM
.
12 AM

diltiazem ER

losartan 50

diltiazem ER

losartan 50
aspirin 81

BP
Reading

9 AM

9 PM
134/ 75
134/75

Ex. #2
(after 1 week)

6 AM
12 PM
6 PM
12 AM

losartan 50

diltiazem ER

losartan 50

diltiazem ER
aspirin 81

BP
Reading

9 AM

9 PM
131/74
131/74

Notes:
1. Two BP readings per day - at 9AM and 9PM
2. Half-life of losartan 50 is about 2 hours
3. Half-life of diltiazem ER 120 is about 8 hours
4. Half-life of aspirin 81 is about 2 hours
5. I am a "non-dipper" - BP highest in morning
6.




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Vaughn's Other
HUMAN BLOOD Related Pages

* Blood INR Chart

*
Blood Test Results

*
Blood Type Summary

*
Cholesterol Range Chart

*
Drug Concentration




Disclaimer
The author is not a doctor.
NO MEDICAL ADVICE IS OFFERED OR IMPLIED.
Statements on this page may NOT be correct.
These are just my personal thoughts.
The sole purpose of this page is to encourage further research on your part.

I hope that you have found this blood concentration level information page helpful.
Thank you very much for your time.

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This Vaughns Medicine Blood Concentration
Chart was updated on 2015-09-02.