Antidepressant tapering calculator

An antidepressant taper calculator creates a tapering schedule based on your current dose and medication type. It uses the hyperbolic method where each step reduces a comparable percentage of the receptor occupation instead of a constant number of drug milligrams. As a result, you will receive a personalized schedule that you can review with your prescriber.

It's just convenient to turn complex pharmacological data into a tangible schedule that you can quickly scan through. An antidepressant taper calculator is especially helpful to those who are tapering off their antidepressants gradually to avoid withdrawal — because the last few milligrams provide the greatest change in modelled SERT occupancy. Moreover, this calculator helps you see the steps in advance, prepare the correct split-tablet dosages, or print out a long-term plan to present to your doctor.

It calculates what proportion of your serotonin transporters are occupied at each dosage using the Hill equation curve model (it describes the relationship between the concentration of the drug and the biological response). Then, the calculator suggests a roadmap to gently reduce your dose with minimal withdrawal symptoms and maintain the same occupancy decrease at each step.

Hyperbolic tapering means decreasing your antidepressant dose by progressively smaller milligram amounts. This model is considered gentler with less withdrawal symptoms, compared to the linear model, because antidepressants exhibit a hyperbolic dose response relationship. At low doses, even a small milligram decrease can produce significant effects. Hyperbolic tapering is recommended by the Maudsley Deprescribing Guidelines (2024), the UK NICE NG222 guideline (2022), and the Royal College of Psychiatrists.

While most patients feel comfortable with reducing their dose by 5-10% every 2-4 weeks, they also tend to slow their taper rate at the final steps. Individuals taking high-risk medications (paroxetine, venlafaxine, duloxetine) often require even slower steps and longer holding periods. Unfortunately, there is no one-size-fits-all timeline for tapering: many people require 6-12 months to completely discontinue their antidepressant therapy, especially after years of antidepressant use.

The most common symptoms include dizziness, "brain zaps" or short-lived electric shock sensation, nausea, fatigue, insomnia, vivid dreams, headaches, irritability, anxiety, and mood swings. According to a recent systematic review, withdrawal symptoms (at least one from the list) occur in approximately 31% of individuals on antidepressants. About 3% of them are more severely affected. Another systematic review suggests that withdrawal rates range from 27% to 86% with an average of 56%. This means that the majority of patients face this challenge, and you're not alone.

Antidepressant withdrawal usually starts within days after a dose reduction and manifests mostly physically (dizziness, nausea) or emotionally (anxiety, irritability). These symptoms typically improve immediately when you reinstate the previous baseline dose. In contrast, relapse generally occurs weeks later, manifests in your original symptoms, and is not alleviated by coming back to the larger dose. Clinicians typically use the Cosci and Chouinard framework with 3 types of withdrawal syndromes as the standardized tool to differentiate between withdrawal and relapse.

Generally not advisable without clinical guidance. Stopping an antidepressant suddenly can cause intense withdrawal symptoms, such as headaches, insomnia, and dizziness, and may make it harder to tell withdrawal apart from relapse. NICE guidance (NG222) notes that the need to taper is not universal, but for most people a gradual, clinically supervised reduction is safer than stopping abruptly. Some medications, like paroxetine and venlafaxine, have very short half-lives and therefore carry the greatest risk. Before making any changes to your treatment plan contact your prescriber.

Tapering becomes difficult during the final stages due to the nature of the dose-SERT occupancy relationship. It's not linear, so when you're taking low doses, even a 1-2 mg change can produce the same effects as a 10-20 mg decrease at higher doses. As a result, patients often report feeling fine through almost all of their taper process, but experience difficulties during the last few steps. This tapering calculator can help you minimize these issues by cutting the final doses only by tenths of a milligram and by preparing for it in advance.

Patients often report paroxetine (Paxil/Seroxat), venlafaxine (Effexor) and duloxetine (Cymbalta) to be the hardest to taper from — due to their short half-lives and hyperbolic dose occupancy curves. This makes abrupt tapering likely to trigger withdrawal symptoms quickly. On the other hand, medications with longer half-lives like fluoxetine (Prozac) are considered easier to taper from. This made them popular as "bridging" agents when switching to a new antidepressant that has a shorter half-life.

The dose of sertraline (Zoloft/Lustral) should also be tapered hyperbolically. A personal plan can vary but a common range is a 10% reduction every 2-4 weeks. Using the scored tablets and the licensed liquid concentrate (for example, 20 mg/ml concentrate for oral solution) are your most convenient options for the last few stages of tapering. If you have 25 mg tablets, you could cut them in half (12.5 mg) first, then to 6.25 mg, but below this point, liquid will be the most practical method.

The one-site Hill equation is the simplest model that fits published PET/SPECT data on antidepressant transporter occupancy. It helps calculate the proportion of transporters occupied at each step and therefore the possible degree of dose reduction. This model is equivalent to the two-parameter Michaelis–Menten equation, where E_max is the plateau occupancy and K_d is the dose at half-maximal occupancy.

Each value was obtained from peer-reviewed PET or SPECT occupancy studies for different antidepressants. When relevant studies were not found directly, they were identified using an established anchor that included a lower bound of confidence (for example, extrapolation from a related agent).

Preset A (faster) corresponds to approximately 5% occupancy per step with a 1-week pause; preset B (moderate) to approximately 2.5% occupancy per step with a 2-week pause; preset C (slower) to approximately 1.5% occupancy per step with a 4-week pause. All three presets fall within per-drug recommendations from the Maudsley Deprescribing Guidelines, the Royal College of Psychiatrists, and the UK NICE NG222 guideline. Based on your pre-taper risk quiz answers, the calculator suggests which preset to begin with; you may select another at any time.

Yes. For each ideal dose we select the nearest possible formulation in your chosen region (UK, NL, and others)—including licensed tablets and capsules, oral liquids where available, and standardised hyperbolic taper strips. If an exact formulation is not available, your plan will note that the step should be discussed with your local pharmacist.

This calculator can help you visualise a tapering schedule and create a step-by-step roadmap. Before making any changes to your medication plan, consult a medical professional. This tool is not a tapering guide for benzodiazepines, antipsychotics, lithium, opioids, or Z-drugs; not a replacement for individual pharmacokinetic, renal/hepatic, or pharmacogenomic (e.g. CYP2D6) assessment; and not a diagnostic tool for distinguishing withdrawal from relapse.