OverviewDosageSide EffectsInteractionsHalf-Life

Hydralazine was the 105th most commonly prescribed drug in the United States in 2017. In that year alone, there were over seven million prescriptions. Considering how popular this drug is right now, it pays to know a little bit more about this medication, including how long hydralazine stays in your system.

Basic Information

Medscape states the following information regarding hydralazine half-life:

Mean effective half-life: about 2-8 hours with normal kidney function 

Time to steady-state: about Two hours by oral route

Mean accumulation ratio: N/A

Terminal phase half-life: about 2 to 8 hours

Hydralazine has an oral bioavailability of about 10% to 31%. This medication is readily absorbed into the blood via the gastrointestinal tract and eliminated through feces and urine. 


What is the half-life of hydralazine?

Two to eight hours for those with normal kidney function. 

How long does hydralazine stay in your system?

Hydralazine is detectable in your system for the following time frames:

  • Your blood for N/A
  • Your saliva for N/A
  • Your urine for N/A
  • Your hair for N/A

Hydralazine is not a drug that would show up in standardized drug tests. It is for the treatment of high blood pressure and not used recreationally like controlled pain medications. For that reason, drug screenings typically do not look for this medication. 

How long does it take for hydralazine to lower blood pressure?

Hydralazine tends to be fast acting, although just how long it takes depends on the delivery route. For oral delivery, it might take 45 minutes. When given as an intramuscular injection or IV push, the time would be significantly less, perhaps anywhere from five to 30 minutes. 

How long does IV hydralazine stay in your system?

It shouldn’t be in the system for longer than 24 hours. 

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.

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