From the Guidelines
The half-life of escitalopram is approximately 27-32 hours. This means it takes about 1-1.5 days for half of the drug to be eliminated from the body. For most patients, this translates to a once-daily dosing schedule, typically 10-20 mg taken in the morning or evening. The long half-life helps maintain steady blood levels of the medication over 24 hours, which contributes to its effectiveness in treating depression and anxiety disorders. Due to this extended half-life, it takes about 1-2 weeks for escitalopram to reach steady-state concentrations in the body when starting treatment, as noted in studies such as 1. Similarly, it may take several days to a week for the drug to be fully eliminated from the system after discontinuation. The long half-life also means that if a dose is missed, the impact on blood levels is less immediate compared to medications with shorter half-lives. However, patients should still aim to take their dose at the same time each day for optimal effect. In elderly patients or those with liver impairment, the half-life may be slightly longer, potentially necessitating dose adjustments, as considered in guidelines like 1 and 1. Always consult with a healthcare provider for personalized dosing information. Some key points to consider when prescribing escitalopram include:
- Starting with a low dose and gradually increasing as needed and tolerated
- Monitoring for symptoms of serotonin syndrome, especially when combining with other serotonergic drugs
- Being aware of potential drug interactions, particularly with drugs that prolong the QT interval
- Considering the patient's medical history, including any history of suicidal thoughts or behavior, and closely monitoring their condition.
From the FDA Drug Label
- 3 Pharmacokinetics ... Biotransformation of escitalopram is mainly hepatic, with a mean terminal half-life of about 27-32 hours. The half-life of escitalopram is 27-32 hours 2.
- The half-life may be increased in elderly subjects, by approximately 50%.
- No adjustment of dosage is needed in adolescent patients.
From the Research
Half-Life of Escitalopram
- The half-life of escitalopram is approximately 27-33 hours, as reported in studies 3, 4, 5.
- This half-life is consistent with once-daily administration, allowing for steady-state concentrations to be achieved within 7-10 days of administration 3.
- The pharmacokinetics of escitalopram are linear and dose-proportional, with the area under the plasma concentration-time curve and maximum observed plasma concentration increasing proportionally with dose 4, 5.
- The half-life of escitalopram is not affected by food intake, and it has a high absolute bioavailability, making it suitable for oral administration 4, 6.
Comparison with Other SSRIs
- Escitalopram has a half-life similar to other SSRIs, such as citalopram, but differs from fluoxetine, which has a longer half-life of 2-4 days and an active metabolite with a half-life of 7-15 days 7.
- The pharmacokinetic properties of escitalopram, including its half-life, make it a suitable option for the treatment of depression and anxiety disorders, with a low potential for drug interactions and a favorable safety profile 3, 5, 6.