Toya asked
I have been on Klonopin (Clonazepam) for 3-4 years. I don't want to start trying to become pregnant until these medications are completely gone from my system. How long does it take for Klonopin to be completely cleared?
Answer
There are many factors that affect how drugs are metabolized and eliminated from the body including concurrent drugs, clinical status, genetics, weight etc... but we can certainly get a general idea of how long it would take for Klonopin (Clonazepam) to be completely cleared.
With Klonopin, you certainly want to err on the side of caution as there is an association with benzodiazepine drugs and increased risk of congenital malformations. In addition, animal data has indicated teratogenic effects of Klonopin specifically.
The reported half-life of Klonopin is approximately 19—50 hours in adults meaning it takes that amount of time for the drug to become 50% metabolized in the body. After another half-life, the concentration of the drug will be reduced by another 50% and so on. Looking at it another way:
- One half-life: 50% of drug remaining
- Two half-lives: 25% of drug remaining
- Three half-lives: 12.5% of drug remaining
- Four half-lives: 6.25% of drug remaining
- Five half-lives: 3.125% of drug remaining
It is generally accepted that after 5 half-lives, the drug is essentially eliminated from the body. In the case of Klonopin, if we use 50 hours as a half life, it would take 250 hours to reach 5 half-lives, or 10.41 days for the drug to be eliminated. Again, this could vary based on the person and you may want to wait a longer period of time to have peace of mind that the drug is completely eliminated from your body. We would recommend speaking to your doctor about your plans to conceive and come up with a plan you are comfortable with concerning drug discontinuation.
