Summary: Duration of Effect vs. Time in the Body

When taking psychiatric medications, there is a massive difference between how long you feel the drug working (Duration of Effect) and how long the chemical actually stays in your blood (Clearance Time).

It takes roughly 5 half-lives for a drug to be 97% eliminated from the human body. Here is how the five major bipolar medications compare.

---

1. Lorazepam (Ativan / Lopez)

• Time the Effect Remains: 6 to 8 hours. The acute sedation, anxiety relief, and muscle relaxation wear off relatively quickly.
• Time the Drug Remains in the Body: 2 to 4 days. The biological half-life is 10 to 20 hours. Even though you stop feeling the sedative effects after 8 hours, trace amounts of the drug remain in your system and can be detected on a drug test for several days.

2. Propranolol (Ciplar / Betacap)

• Time the Effect Remains: 4 to 6 hours for immediate-release tablets, or 24 hours for extended-release (LA) capsules. The tremor control wears off quickly with standard tablets.
• Time the Drug Remains in the Body: 1 to 2 days. The half-life is very short (3 to 6 hours), meaning the body clears it rapidly. This is why abrupt withdrawal causes a sudden, dangerous spike in blood pressure.

3. Sodium Valproate (Valparin / Encorate)

• Time the Effect Remains: Continuous. Because it alters gene expression and neurotransmitter levels to stabilize mood, the clinical effect is maintained 24/7 as long as daily dosing continues.
• Time the Drug Remains in the Body: 3 to 4 days. The half-life is 9 to 16 hours. If you stop taking it, the active chemical will be entirely flushed from your system within 80 hours, though the risk of rebound mania begins almost immediately as blood levels drop.

4. Escitalopram (Nexito / Rexipra)

• Time the Effect Remains: Continuous. SSRIs cause structural changes in the brain (neurogenesis) over weeks of use. The antidepressant effect does not switch off immediately if you miss a dose by a few hours.
• Time the Drug Remains in the Body: 6 to 7 days. The half-life is long (27 to 32 hours). Because it stays in the body for nearly a week, doctors require a strict 14-day “washout period” before allowing a patient to start an MAOI drug, to prevent fatal Serotonin Syndrome.

5. Olanzapine (Oleanz / Olimelt)

• Time the Effect Remains: 12 to 24 hours. The heavy sedation (the “hangover” effect) is usually felt most intensely for the first 12 hours after taking the dose, but the antipsychotic effect lasts continuously.
• Time the Drug Remains in the Body: 5 to 11 days. Olanzapine has an incredibly long half-life (21 to 54 hours, depending on age, gender, and smoking status). If you stop taking Olanzapine, your body will still be slowly filtering it out of your blood over a week later.

---

Return to Index: The Comprehensive Bipolar Disorder Medicines Guide