Calculating drug steady state achieved (hours) - Evidencio
Calculating drug steady state achieved (hours)
The steady state of drug intake regards a constant mean concentration of a drug in which the elimination and absorption of the drug is equal. The time to achieve steady state is relying on the half-life of the drug. This formula can be used to quickly assess how long it would take to achieve steady state.

Mostly, 4-5 half-lives are used to achieve clinical steady state
Research authors: None
Version: 1.5
  • Public
  • Clinical pharmacology
  • Custom calculation
  • Details
  • Validate algorithm
  • Save input
  • Load input

Drug half-life

0
200
hours

Desired half-lives

1
8
Half-Lives

Time to achieve steady state is ... hours

Set all parameters to calculate prediction.

If the time to achieve steady state is longer than desired, an initial loading dose of a drug can be administered to reach the desired blood concentration quickly.
Note: The loading dose is based on the volume of distribution and the maintenance dose is based on the half-life of the drug administered. 

This algorithm is provided for educational, training and information purposes. It must not be used to support medical decision making, or to provide medical or diagnostic services. Read our full disclaimer.

Recent algorithms
Part of
Comments

Algorithm feedback

5 Comments
On 2018-02-08 15:24:39 sbstrum wrote:
Great start. What would be important is to expand the drug half-life given that some drugs (shown below) have half-lives much longer than 50 hours. So show option for hours & days. <br /> <br /> Half-life of various anti-androgens:<br /> Flutamide 5.2 hrs<br /> Nilutatmide 45 hrs<br /> Apalutamide (ARN-509) 3-4 days (72-96 hours)<br /> Bicalutamide 6 days (144 hrs)<br /> <br /> Then make it easier for the clinician by having time to steady state shown in both hours and days. I realize the latter is simply division but it makes the app expedient. <br /> Stephen B. Strum, MD, FACP
On 2018-02-19 09:30:50 T. A. Hueting wrote:
Thank you for the feedback. We've updated the model and allows half lives up to 200 hours. <br /> <br /> Calculate both days and hours in a single input with this link: https://www.evidencio.com/models/show/1135
On 2018-04-09 13:29:35 sbstrum wrote:
A new treatment is proposed as the initial program for metastatic hormone-naive prostate cancer (mHNPC) . This involves a drug called abiraterone (Zytiga®) which works to block adrenal gland androgen precursor synthesis while also inhibiting intra-tumor androgen production and testicular androgen synthesis. But in men starting on abiraterone + an LHRH agonist like Lupron, there is a major concern about testosterone flare 2° initial use of Lupron. Knowing the time to achieve steady state for abiraterone is therefore key. The prescribing information (PI) says abiraterone may have a half-life of 12 ± 5 hours. Calculations of Time to Achieve Steady State (TTASS) are therefore important.
On 2018-04-12 14:12:55 sbstrum wrote:
Suggest also provide result in days + hours when 24 hrs exceeded. It just adds a nice touch. <br /> <br /> Perhaps, since most Time to Achieve Steady State (TTASS) calculations are based on 4-5 half-lives it would also be nice to have a category "4-5 half-lives) with results as <br /> <br /> 4-5 half-live range with median: 240-300hrs [10d-12.5d]; average 270hrs (11.25d)
On 2023-09-11 08:30:38 Half Life Calculator wrote:
Awesome model!<br /> <br /> What was lacking for me was some visual representation of the data, so I ended up creating a dedicated <a href="https://www.half-life-calculator.com" style="font-weight:bold">drug half life calculator</a> that also shows steady state.<br /> <br /> I hope it helps, and any feedback is appreciated!
logo

Please sign in to enable Evidencio print features

In order to use the Evidencio print features, you need to be logged in.
If you don't have an Evidencio Community Account you can create your free personal account at:

https://www.evidencio.com/registration

Printed results - Examples {{ new Date().toLocaleString() }}

Evidencio Community Account Benefits

With an Evidencio Community account you can:

  • Create and publish your own prediction algorithms.
  • Share your prediction algorithms with your colleagues, research group, organization or the world.
  • Review and provide feedback on algorithms that have been shared with you.
  • Validate your algorithms and validate algorithms from other users.
  • Find algorithms based on Title, Keyword, Author, Institute, or MeSH classification.
  • Use and save prediction algorithms and their data.
  • Use patient specific protocols and guidelines based on sequential algorithms and decision trees.
  • Stay up-to-date with new algorithms in your field as they are published.
  • Create your own lists of favorite algorithms and topics.

A personal Evidencio account is free, with no strings attached!
Join us and help create clarity, transparency, and efficiency in the creation, validation, and use of medical prediction algorithms.

Disclaimer: Calculations alone should never dictate patient care, and are no substitute for professional judgement.
Terms & Conditions | Privacy Policy | Disclaimer | Contact | Refuse cookies |
Evidencio v3.36 © 2015 - 2025 Evidencio. All Rights Reserved