Prescribing guided by your genes
Pharmacogenetic testing
If you have worked through several medications without finding one that suits you, the problem may not be the medication. It may be how your body processes it. A genetic test can tell you which is which.
The problem
Trial and error is the standard approach, and it is slow
The usual way to find the right antidepressant is to try one, wait six to eight weeks, and see. If it does not help, or the side effects are too much, you try another, and wait again.
People describe losing years to this. Each round costs weeks of waiting and a period of feeling worse before you know whether it was worth it, and after three or four attempts it is easy to conclude that nothing works for you.
Sometimes nothing does. But often the medication was reasonable and the dose was wrong for your body, and nobody had any way of knowing.
How it works
Fast and slow metabolisers
Your body breaks medication down using enzymes, and the genes that produce those enzymes vary from person to person. That variation changes how much of a drug is actually circulating in you at a given dose. Take citalopram, a common antidepressant.
| Feature | Slow metaboliser | Rapid metaboliser |
|---|---|---|
| What your body does | Clears the drug slowly | Clears the drug quickly |
| At a standard dose | It builds up | Little of it is left |
| What you notice | More side effects than the prescription suggests | The drug appears to do nothing |
| What is usually needed | A lower dose | A higher dose, or a different drug |
The same medication, the same dose, and two people who need completely different prescriptions. A pharmacogenetic test looks at the genes responsible and reports where you sit for each drug.
Your options
Mental health, or everything
Mental health panel
Psychiatric medication, including ADHD medication. Around 90% of commonly prescribed psychotropic medications are covered.
Best for someone working through psychiatric prescribing now.
Comprehensive panel
The same, plus medication for diabetes, asthma, heart conditions and cancer.
Best for someone who wants the result to be useful for the rest of their life.
Both use a cheek swab you take yourself at home, and both take around two weeks to come back.
The process
Five steps, about three weeks
An assessment with Dr Nabavi
We go through your history and what you have already tried, and decide whether testing is likely to tell you anything useful.
Your kit arrives
You take the swab yourself, at home. There is no blood test.
The sample goes to the laboratory
A UK laboratory, not an overseas service.
Results in about two weeks
Reported drug by drug, showing where you sit for each one.
A consultation to go through them
What the report says, what it means for what you are taking now, and what we would suggest instead. With your permission we write to whoever prescribes for you.
We pass the lab’s discount to you
The laboratory offers us a commission of 20 to 25% on every kit we refer. We do not take it. The discount goes to you instead, so patients who come through this clinic buy the kit for 20 to 25% less than they otherwise would.
We would rather be paid for our clinical time than take a margin on a test we are recommending. It also means that when we suggest testing, you can be reasonably sure we are suggesting it because it will help.
Honest limits
It guides prescribing. It does not decide it.
In the largest randomised trial of genetically guided prescribing, 1,541 patients with depression were assigned either to guided care or to treatment as usual. More people responded and more reached remission with guided care, and the difference was statistically significant. The trial’s main continuous measure of symptom improvement did not reach significance.
Greden et al. (2019), Journal of Psychiatric Research 111: 59-67.
So: a useful input, not an answer. We would rather you knew that before you paid for it.
What it can tell you
How you are likely to metabolise a given medication, why a previous drug may have caused unusual side effects, and where a dose is likely to have been too high or too low.
What it cannot tell you
Which medication will work. Response to psychiatric medication depends on much more than metabolism, and no genetic test predicts it.
The result does not expire
Your genes will not change. You keep a copy, and a doctor prescribing for blood pressure or diabetes in ten years can read the same report.
What it costs
£400 and £250
£400 for the assessment with Dr Nabavi, and £250 for the consultation that goes through your results.
The test kit is bought from the laboratory directly, with the 20 to 25% discount above. One recent patient paid under £200 for the comprehensive panel. We will confirm the current kit price when you call.
Common questions
About two weeks from the laboratory receiving your sample.
Many do. We write to them with a clear explanation of what the result means and what we suggest, which makes it easier to act on than a report arriving on its own. The prescribing decision remains theirs.
Possibly not for the medication you are on now. It may still be worth it if you have had bad reactions in the past and want to know why, or if you want the result on file for the future.
No. The test looks at your genes, not at what is in your bloodstream.
You can, and some people do. What you would not get is someone to interpret it in the context of your psychiatric history, or a letter to your prescriber explaining what to do about it. The report on its own is difficult to act on.
Find out whether testing would tell you anything useful
Testing is not useful for everyone. Dr Nabavi looks at your medication history first and only suggests a kit if the result is likely to change your prescription.