The challenge
When a patient on an SSRI experiences side-effects they can't tolerate, the standard response is to switch them to a different drug and wait. If that one doesn't suit them, switch again. In practice, this trial-and-error cycle can stretch over months — each iteration requiring time for the drug to reach therapeutic effect, followed by a taper and washout before starting the next. For patients already struggling, that wait carries real cost.
The underlying problem is that SSRIs are not pharmacologically interchangeable. They differ substantially in how they interact with neuroreceptors beyond their primary target — serotonin transporters — and it is often those secondary interactions that drive side-effects. A drug that blocks histamine receptors tends to cause sedation. One with strong muscarinic activity may cause dry mouth or cognitive fog. One with significant action at 5-HT2A receptors will have a different tolerability profile again. This information exists in the pharmacological literature, but it is scattered, technical, and not presented in a form that supports clinical decision-making in a consultation.
What we built
ReceptorMap is an interactive clinical tool that maps the receptor binding profiles of antidepressants, allowing clinicians to compare drugs on a given receptor and understand how they differ. For any selected receptor, the tool plots all relevant drugs on an axis from antagonist to agonist — ranked by binding affinity (pKi) — so the pharmacological distance between a patient's current drug and potential alternatives is immediately visible.
A clinician whose patient is experiencing a side-effect associated with a specific receptor can use the tool to find drugs with weaker activity at that target, without abandoning the broader therapeutic class. Rather than switching blindly, they can switch with a reason.
Why this matters
SSRI prescribing is among the most common interventions in primary care, and side-effect-driven discontinuation is one of the leading causes of treatment failure in depression. Evidence consistently shows that patients who discontinue early are at greater risk of relapse and longer episodes. Better-informed switching decisions — grounded in pharmacology rather than trial-and-error — give patients a faster route to a regimen they can stay on.
The tool is not a prescribing protocol and is not intended to replace clinical judgement. It is decision support: a way of bringing relevant pharmacological evidence into the room at the moment it is needed, structured to be usable in the time a consultation allows.