Antidepressant glossary Short, plain-English definitions of the terms that come up when you start, switch, or stop an antidepressant. Each term page points to a tool or guide you can use with your prescriber.
Written by Alena Kozlova, PhD , from published studies and prescribing information.
Withdrawal Antidepressant discontinuation syndrome : Antidepressant discontinuation syndrome, also called antidepressant withdrawal, is the set of physical and emotional symptoms that can appear when the brain and body have adapted to an antidepressant taken for a month or more and then get less of it, as after a sudden stop, a sharp cut or a missed dose. Common signs are dizziness, nausea, flu-like aches, tiredness, brain zaps, poor sleep, irritability, anxiety and low mood. For many people symptoms are mild and pass within a couple of weeks, but for some they are severe or last for months. Also called: Antidepressant withdrawal, SSRI discontinuation syndrome.Antidepressant half-life : An antidepressant’s half-life is the time it takes for the amount of the drug in your blood to fall by half. It shapes how soon, and how likely, withdrawal symptoms are after a missed dose or a cut. For some drugs, such as fluoxetine, what the drug turns into in the body lasts longer still. Half-life is only part of the picture, so withdrawal can still happen with longer-acting drugs. Also called: Half-life.Brain zaps : Sudden, brief jolts that feel like a small electric shock or a buzz in the head, and sometimes in the arms or legs, during antidepressant withdrawal. Turning the head or moving the eyes can set them off. Also called: Electric shock sensations, Brain shivers, Head zaps.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.Stopping antidepressants cold turkey : Going cold turkey means stopping an antidepressant abruptly, all at once, instead of lowering the dose in steps. Guidelines advise against it, because after a month or more of regular use it is more likely to bring on withdrawal symptoms than a gradual reduction, especially with antidepressants that leave the body quickly, such as paroxetine or venlafaxine. Stopping suddenly can also make an early return of depression more likely, so talk to your prescriber first. Also called: Cold turkey, Stopping antidepressants suddenly, CT.Tapering and dose forms Bead counting : Bead counting is an informal way of taking less than the smallest capsule strength by opening a capsule that contains small beads and taking only some of them. It is outside the product licence and the dose is only approximate. Duloxetine’s prescribing information says its capsules should not be opened. It should only be done with a prescriber’s agreement, after licensed options such as a lower strength or a liquid have been considered. Also called: Counting beads, Weighing the beads.Hyperbolic tapering : Hyperbolic tapering is a way of lowering an antidepressant dose in steps that get smaller as the dose gets lower, often down to very small doses before stopping. It is based on the finding that at low doses even small cuts have a large effect in the brain. In practice each step is usually a share of the current dose. Guidelines recommend reducing this way, although trials comparing it with other methods are still under way. Also called: Hyperbolic taper, Proportional tapering.Liquid antidepressants : A liquid formulation is a medicine made as a liquid instead of a tablet: an oral solution, ready to measure, or a concentrate, a stronger liquid that is diluted just before you take it. With antidepressants it lets you measure doses smaller than any tablet, which helps in the last steps of a taper. Not every antidepressant comes as a liquid, and a liquid dose is not always the same as the tablet dose in milligrams, so the change is worked out with a prescriber or pharmacist and measured with an oral syringe. Also called: Liquid formulation, Oral solution, Liquid Lexapro, Liquid sertraline, Oral concentrate.Pill splitting : Pill splitting is cutting a tablet into parts to get a dose no tablet comes in, most often during a taper. It suits scored tablets, and others a pharmacist confirms can be split, using a tablet cutter. Extended-release, enteric-coated and orally disintegrating tablets should not be split unless the leaflet says it is safe, and capsules cannot be. Pieces from unscored tablets can be uneven. Also called: Tablet splitting, Pill cutter.Tapering off antidepressants : Tapering is lowering an antidepressant dose in planned steps over time, instead of stopping it at once. After a month or more on an antidepressant, and more so after months or years, the brain has adapted to it, and gradual steps give it time to readjust, which lowers the risk of withdrawal symptoms and leaves room to slow down if they appear. It is usually done with a prescriber, at a pace adjusted to how the person feels. Also called: Tapering, Tapering off, Weaning off, Dose reduction.Switching medication Antidepressant washout period : A washout period is the gap between stopping one antidepressant and starting another, so the first drug can leave your body before the second begins. It is needed mainly when one of the two is an MAOI, and when switching from fluoxetine, which stays in the body for weeks. The gap prevents dangerous interactions such as serotonin syndrome, but it can bring on withdrawal symptoms from the first medication. Also called: Washout period, Washout, Drug-free interval.Cross-tapering : Cross-tapering is switching antidepressants by lowering the first one while starting the second, so you take both for a while. It avoids a stretch without treatment and can soften withdrawal from the first, but taking two at once can raise side effects, including serotonin syndrome. It is never done when switching to or from an MAOI, which needs a gap instead. Also called: Cross-taper, Overlap switch.Direct switch between antidepressants : A direct switch means stopping one antidepressant and starting another the next day, with no overlap in the medication you take and no gap between them. Prescribers use it mainly between two medications of the same kind, such as two SSRIs. It is not used when switching from fluoxetine, which stays in the body for weeks, or to or from an MAOI. Also called: Direct switch, Switching antidepressants directly, Straight switch.Prozac bridge : A Prozac bridge is an informal name for a way of coming off a short-acting antidepressant by switching to fluoxetine (Prozac) and then tapering the fluoxetine instead. Fluoxetine and the substance it turns into leave the body over weeks, so after each cut the level falls slowly on its own instead of dropping within a day. It is off label and based on clinical experience rather than trials. The switch needs a prescriber, because fluoxetine works differently from some of the drugs it replaces and can interact with them. Also called: Fluoxetine bridge, Bridging with Prozac.Tools For clinicians Company Legal