Medications
Antidepressants: SSRIs explained
A widely used class of antidepressant in Australia — how they work, what to expect, and how they are stopped safely.
How long it takes
Most people feel better after 2–4 weeks; it can take 6–8 weeks for the full effect. Keep taking it as prescribed even once you feel well.
What SSRIs are
Selective serotonin reuptake inhibitors (SSRIs) are a widely used and usually well tolerated class of antidepressant. Examples include sertraline, escitalopram, citalopram, fluoxetine, fluvoxamine and paroxetine. They are not interchangeable — the conditions they are approved for, their interactions, their doses and how they are stopped all differ between products.
How they work
SSRIs change the way the brain handles serotonin, a chemical messenger involved in mood, emotion and sleep. Exactly how that improves symptoms is not fully understood, and depression is not simply a shortage of one brain chemical. Benefit usually builds over several weeks and varies from person to person, so progress is reviewed rather than assumed.
Side effects and stopping
Early side effects such as trouble sleeping, nausea, stomach upset, dizziness or sexual difficulties often ease after a few weeks. Tell your doctor promptly about marked restlessness, new or worsening thoughts of self-harm, or a sudden lift in mood and energy. Some medicines, including other serotonin medicines and those affecting bleeding, need to be checked before they are added.
Not addictive, but stopping still needs a plan
SSRIs are not addictive and are not a drug of dependence. That is not the same as stopping being easy — withdrawal symptoms such as dizziness, flu-like feelings, irritability or electric-shock sensations can follow a dose reduction or stopping. Do not stop suddenly. Reduction is worked out with your doctor for you and your medicine, not from a fixed taper that suits everyone, and withdrawal is checked against the possibility that the original condition is returning.
If you have ever had a high or manic period
Tell your prescriber about any past period of unusually elevated or irritable mood, reduced need for sleep, racing thoughts or out-of-character risk-taking. A history of mania or hypomania changes both the assessment and the prescribing decision, and this general SSRI sheet is not a recommendation to treat bipolar depression with an antidepressant on its own.
When to get urgent help
If you have thoughts of harming yourself, a seizure, fainting or a sustained irregular heartbeat, or a fever with agitation, tremor or stiff muscles, get help straight away rather than waiting for your next appointment. Go to your nearest emergency department or call 000. In Australia you can call 13YARN 13 92 76, Beyond Blue 1300 22 4636, Lifeline 13 11 14, or 000 in an emergency.
Where this information comes from
More in Medications
See allDemonstration content — not clinician-approved. Governance-approved patient information must replace it before any clinical use or sharing.
This sheet is general information, not personal medical advice. Always follow the instructions from your own doctor or pharmacist.