Missed antidepressant dose A missed dose is a scheduled dose of an antidepressant that you did not take at its usual time and only remember later, or not at all. With antidepressants that leave the body quickly, even one missed dose can bring on withdrawal symptoms within a day.
Also called: Missed dose, Skipped dose.
Written by Alena Kozlova, PhD , from published studies and prescribing information.
Definition medically reviewed by Dr. Jason Tan , Consultant Psychiatrist, on October 28, 2026, this definition only. Next review: October 28, 2027.
What should you do if you miss a dose? If you miss a dose, take it when you remember, unless the next one is nearly due. Do not take two doses at once to make up for it. Your prescribing information gives the exact rule.
Medications that leave the body quickly are the most likely to cause symptoms after a missed dose, such as dizziness or brain zaps. People sometimes mistake this for the illness returning. Taking the usual dose again usually settles it.
If you have missed several days, talk to your prescriber or pharmacist before restarting.
What if the next dose is nearly due? Skip the missed dose and take the next one at the usual time, without doubling up. That is what the Zoloft medication guide says, for example. Ask your pharmacist how close to the next dose counts as nearly due for your medication.
What if you take an extra dose by mistake? If you take an extra dose by mistake, call Poison Control at 1-800-222-1222 in the US, or your local poison center, even if you feel fine. Poison Control lists medications for depression among those that can be serious when double dosed, and it can tell you whether you need care. If you feel faint or have a racing heart, a seizure or confusion, call 911 or your local emergency number, or ask someone with you to call.
Which antidepressants cause symptoms after one missed dose? The ones with the shortest half-lives. By their US prescribing information, venlafaxine has a half-life of about 5 hours, and the active substance it turns into about 11, so a late dose can be felt the same day. Other medications with a half-life of a day or less, such as desvenlafaxine at about 11 hours, duloxetine at about 12 and paroxetine at about 21, can bring symptoms on within a day or two. Fluoxetine is the opposite case: it and the substance it turns into last for days, so one missed dose usually makes little difference. The table below compares five common antidepressants.
What people on Reddit say
Of 1,185 people who described coming off an SSRI or SNRI on Reddit, 59 said a missed or late dose brought on symptoms; 20 of them were among the 295 on r/effexor. People who write about coming off are not typical of everyone who misses a dose, so this shows what happens, not how often.
From public Reddit posts, counted by withClaro. These are self-reports, not a clinical study.
Half-life by antidepressant Half-lives of five common antidepressants, shortest first.
Half-lives of all antidepressants
How can you miss fewer doses? Take the dose at the same time each day and tie it to something you already do, like breakfast. A phone reminder helps, and so does keeping a few days of tablets wherever you stay overnight. With venlafaxine or paroxetine a late dose is felt sooner, so a few spare tablets in your bag matter more than with fluoxetine.
What to do Ask your prescriber or pharmacist what the rule for a missed dose is for your medication, and write it down. If symptoms after a missed dose do not settle once you are back on your usual dose, tell your prescriber when the dose was missed and when the symptoms started.
Check whether a symptom is common
How withClaro helps Your doses logged, so a missed or late one shows up in your record Symptoms next to your doses, if a missed dose leaves you feeling off Get the withClaro app on the App Store
Related terms Sources U.S. Food and Drug Administration. Effexor XR (venlafaxine extended-release capsules): prescribing information. FDA / DailyMed, 2025. Eli Lilly and Company. Cymbalta (duloxetine delayed-release capsules): prescribing information. Eli Lilly, 2023. U.S. Food and Drug Administration. Paxil (paroxetine) tablets: prescribing information. FDA / DailyMed, 2026. U.S. Food and Drug Administration. Prozac (fluoxetine): prescribing information. FDA / DailyMed, 2026. U.S. Food and Drug Administration. Zoloft (sertraline) tablets and oral solution: prescribing information. FDA / DailyMed, 2025. National Capital Poison Center. Double dosing: what to do if you take too much. Poison Control (poison.org), 2024. Gury C, Cousin F. Pharmacokinetics of SSRI antidepressants: half-life and clinical applicability. L'Encéphale, 1999. Horowitz M, Taylor D. Distinguishing relapse from antidepressant withdrawal: clinical practice and antidepressant discontinuation studies. BJPsych Advances, 2022. All glossary terms