TaperCommunity
Calculating a taper schedule means deciding how much of a dose to cut, and how often, without triggering withdrawal symptoms. The most common mistake is using fixed dose drops (cutting 5mg every month, for example) all the way to zero. That approach ignores how these medications actually work in the brain, and it is why so many people feel fine for months and then crash hard in the final stretch. A safer method calculates each reduction as a percentage of the current dose, not a fixed amount, and slows down as the dose gets smaller. This article walks through the actual math, why it matters pharmacologically, and how to build a schedule around it.
Most standard taper advice looks something like "reduce by 5mg every 2 to 4 weeks" until you reach zero. That schedule is easy to write on a prescription pad, but it does not match how these drugs bind to receptors in the brain.
Psychiatric medications, especially SSRIs and SNRIs, follow a hyperbolic relationship between dose and receptor occupancy. At low doses, small changes in mg produce large changes in effect at the receptor. At higher doses, the same mg change produces almost no change in effect. A drop from 20mg to 15mg of Lexapro barely registers at the receptor level. A drop from 5mg to 2.5mg can feel like falling off a cliff, because that region of the dose curve is where the drug is doing most of its remaining work.
This is the core finding behind hyperbolic tapering, described by Horowitz and Taylor in a widely cited 2019 paper in The Lancet Psychiatry, "Tapering of SSRI treatment to mitigate withdrawal symptoms." Their analysis of PET imaging data showed that serotonin transporter occupancy does not decline in a straight line as dose decreases. It declines steeply at low doses and flattens at high doses. A taper schedule that ignores this curve front-loads easy cuts and back-loads brutal ones, which is exactly backward from what the brain needs.
Bottom line: fixed mg reductions feel fine early and get progressively worse, because the pharmacology of receptor occupancy is not linear.
The correction is straightforward once you see it. Instead of cutting a fixed number of milligrams, each reduction is calculated as a percentage of the dose you are currently on, not the original starting dose.
The formula: new dose = current dose × (1 − reduction percentage)
A common starting point is a 10% reduction of the current dose, held for 4 to 6 weeks before the next cut, though the Maudsley Deprescribing Guidelines note that some people need reductions as small as 5%, and others tolerate 10 to 20% comfortably. There is no single number that works for everyone; the percentage is a starting hypothesis you adjust based on how the body responds.
Here is what that looks like in practice on a 20mg starting dose, using 10% cuts:
| Step | Current dose | Reduction | New dose | ||--------------|-----------|----------| | 1 | 20mg | 10% | 18mg | | 2 | 18mg | 10% | 16.2mg | | 3 | 16.2mg | 10% | 14.6mg | | 4 | 14.6mg | 10% | 13.1mg | | 5 | 13.1mg | 10% | 11.8mg | | 6 | 11.8mg | 10% | 10.6mg |
Notice the mg amount of each cut shrinks as the dose gets lower: 2mg, then 1.8mg, then 1.6mg, and so on. That is the entire point. Because 10% of a smaller number is a smaller number, the reductions automatically get gentler exactly where the receptor curve gets steepest. This is why the method is called hyperbolic tapering: the dose curve, plotted over time, traces a hyperbola rather than a straight line.
Bottom line: calculating each cut as a percentage of the current dose, not the starting dose, automatically slows the taper down as you approach zero.
Two variables control the schedule: the size of each percentage cut, and how long you hold each dose before cutting again. Both should be adjusted based on symptoms, not a fixed calendar.
A conservative starting point for most people beginning a taper is 10% of current dose, held for at least 4 weeks. If withdrawal symptoms appear (dizziness, brain zaps, irritability, flu-like feelings, mood swings) the hold period gets extended until symptoms settle, not shortened. If a 10% cut feels manageable with minimal symptoms, some people move to a 4-week hold with confidence; others prefer 6 to 8 weeks throughout, especially after long-term use.
People who have been on a medication for many years, or who have had a difficult experience tapering before, often do better starting smaller, at 5% of current dose. It takes longer, but a taper that takes an extra 6 months and works is better than one that is fast and fails.
The NICE guideline NG222 on medicines associated with dependence and withdrawal explicitly recommends individualized, symptom-guided tapering over fixed schedules, and states that some patients may need tapers lasting many months to years for long-term use. This is a significant shift from older guidance that assumed a few weeks was always enough.
Bottom line: start conservative, adjust the percentage and hold time based on how you actually feel, and never let a calendar override your symptoms.
This is the part that surprises almost everyone, and it is also the part most fixed-dose schedules get catastrophically wrong. If a person tapers correctly to this point, the final stretch, going from something like 2mg down to 0mg, often takes as long as the entire rest of the taper combined.
That is not a flaw in the plan. It is the direct consequence of the hyperbolic receptor curve. Because so much of the drug's effect on serotonin transporter occupancy happens at low doses, those last few milligrams represent a disproportionate share of the drug's total pharmacological activity. Jumping from 2mg straight to zero can produce withdrawal symptoms just as severe as a poorly managed jump from 20mg to 10mg, because in terms of receptor occupancy, those two jumps can be comparable in size.
For medications that only come in fixed-strength tablets, this final stretch is where compounding pharmacies, liquid titration, or dose-measuring tools become genuinely necessary rather than optional. Cutting a tablet in half only gets you so far when the therapeutic difference between 1mg and 0.5mg still matters.
Bottom line: expect the last few milligrams to take proportionally longer than any other stage of the taper, and plan the schedule around that reality instead of rushing the ending.
The percentage formula stays the same regardless of the drug, but half-life changes how withdrawal actually feels between cuts, which affects how you should interpret symptoms while calculating hold times.
Medications with a short half-life, like Paxil (paroxetine) or Effexor (venlafaxine), clear the body quickly. That means blood levels drop fast after each reduction, and withdrawal symptoms tend to show up within a day or two of a cut and can hit harder. For these drugs, a smaller percentage cut (5% rather than 10%) and a longer hold are usually the safer default, even for a first attempt.
Medications with a longer half-life, like Prozac (fluoxetine), clear more slowly, which naturally smooths out the drop in blood levels after each reduction. This is part of why fluoxetine is sometimes used as a bridging strategy in clinical settings, though that decision belongs with a prescriber and is outside the scope of a self-calculated schedule.
The FDA drug label database lists elimination half-life for each approved medication, and it is worth checking before you finalize a percentage and hold time. A 10% cut on a short half-life drug and a 10% cut on a long half-life drug are the same math, but they do not feel the same in week one.
Bottom line: the same percentage formula applies to every drug, but a shorter half-life usually means faster, sharper symptoms after each cut, which argues for smaller reductions and longer holds.
Recalculating 10% of a shrinking number every few weeks, tracking hold times, and adjusting for symptoms is exactly the kind of repetitive arithmetic that is easy to get wrong under stress, especially while also managing withdrawal symptoms. This is where a dedicated tool is worth using instead of a spreadsheet built at 1am.
Our team is building a full taper planner that will generate a personalized hyperbolic schedule from your starting dose, formulation, and preferred hold time, and let you adjust it as you go. It is not live yet, but while it's in development, you have two ways to build and track a percentage-based schedule today.
Start with our tapering plan worksheet, which walks through the same percentage-of-current-dose method described above and helps you lay out each step before you begin. Then use Taper Community's symptom journal to log how each reduction actually feels, so you have real data, not guesswork, to decide when to hold longer or move to a smaller percentage.
Bottom line: you do not need to be a pharmacologist to build a safe schedule, but you do need a system that recalculates percentages of the current dose and tracks your symptoms alongside it.
The patient community at Surviving Antidepressants has documented thousands of individual tapers using this same percentage-based approach over more than a decade, and their forum archives are a useful sanity check when you are deciding how your own symptoms compare to a typical taper.
A calculated schedule is a proposal, not a prescription. Bringing a clear, written plan to a prescriber, rather than asking them to design one from scratch, dramatically improves the odds of getting a collaborative response.
A useful document includes your current dose and how long you have been on it, the percentage reduction you are proposing (start conservative, 5 to 10%), your proposed hold time between cuts, and what formulation options exist for your specific medication (tablet, capsule with beads, liquid). If your prescriber is unfamiliar with hyperbolic tapering, printing the Maudsley Deprescribing Guidelines summary for your drug class or the NICE NG222 recommendations gives them something concrete to work from rather than an unfamiliar concept explained secondhand.
If your prescriber is not receptive to this approach at all, our find a deprescriber directory lists clinicians who are specifically familiar with slow, symptom-guided tapering.
Bottom line: a written, percentage-based schedule turns a vague request into a concrete plan your prescriber can actually evaluate.
Is a 10% taper schedule safe for everyone? Ten percent of current dose is a reasonable starting point for many people, but it is not universal. Some people, especially after years on a medication or with a history of difficult withdrawal, do better starting at 5%. Watch for symptoms in the first reduction and adjust from there rather than committing to one number for the entire taper.
How long does a full taper usually take using this method? It depends heavily on the starting dose, the drug's half-life, and individual tolerance, but tapers using percentage-based hyperbolic reductions commonly take anywhere from several months to over a year for long-term use. This is longer than older "few weeks" advice, and that is intentional.
Can I use this same math for benzodiazepines or antipsychotics? The percentage-of-current-dose principle applies broadly, but benzodiazepines and antipsychotics have their own specific guidance and conversion considerations. For benzodiazepines specifically, the Ashton Manual is the standard reference and should be consulted alongside the general hyperbolic principle described here.
What if my medication doesn't come in small enough doses to cut by 5-10%? This is common with fixed-strength tablets. Options include tablets that can be split, switching to a liquid formulation, using a compounding pharmacy for custom low-dose capsules, or in some cases alternating doses on different days to approximate a smaller average daily dose. Discuss formulation options with your pharmacist or prescriber before starting.
Do I need my doctor's permission to calculate my own schedule? You do not need permission to do the math, and understanding your own taper is valuable regardless. But changing your actual dose should happen with medical support when possible, both for prescription and formulation reasons and for safety monitoring. Bring your calculated plan to that conversation rather than skipping it.
If you are building your own schedule, Taper Community has a symptom journal, a planning worksheet, and a directory of tapering-informed prescribers to support the process. You do not have to figure this out alone.
This article is for educational purposes and does not replace individualized medical advice. Always involve a qualified prescriber when changing psychiatric medication doses.