SSRI and SNRI
Selective Serotonin Reuptake Inhibitors (SSRIs) or Serotonin and Noradrenaline Reuptake Inhibitors (SNRIs) may be added to current PoTS medications, when others such as fludrocortisone and midodrine have not achieved the desired symptom control.
Examples of those used in PoTS
SSRIs – paroxetine, citalopram, escitalopram , sertraline
SNRIs –bupropion, venlafaxine, duloxetine, atomoxetine, *reboxetine
What are SSRIs and SNRIs commonly used for?
SSRIs and SNRIs are primarily used in the management of depression and anxiety.
Other common uses include:
Bupropion (Zyban) – smoking cessation
Duloxetine – stress incontinence, diabetic nerve pains, fibromyalgia
Why should I take an SSRI/SNRI when I am neither depressed nor anxious?
Serotonin and noradrenaline are natural chemicals made by our body and are found in the brain and nerve endings. They have many roles, including the regulation of heart rate, blood pressure and gut movement. It is thought that the production and regulation of serotonin is faulty in people with autonomic dysfunction such as PoTS.
These drugs been used in the management of vasovagal syncope (fainting) and orthostatic hypotension (low BP when standing), although exactly how, and if they work remains uncertain.
SSRIs may also improve symptoms of irritable bowel syndrome, which is common in PoTS.
*Some patients report having found the quality of sleep to be improved whilst taking SSRIs.
Which one should I try?
Even though SSRIs are similar to each other, if you do not respond to or tolerate one, you may have better success with another.
Sertraline, citalopram and escitalopram tend to be better tolerated than other SSRIs such as paroxetine, which also carries the highest risk of developing withdrawal side effects.
SNRIs can worsens tachycardia in patients with PoTS due to the increase in circulating noradrenaline.
SNRIs which have been used in the management of PoTS include bupropion, venlafaxine, duloxetine, atomoxetine and reboxetine*
What are the side effects of SSRIs/SNRIs?
Some of the common side effects you may experience include:
- Difficulty in sleeping, abnormal dreams, tiredness
- Nausea, vomiting, diarrhoea, constipation, stomach pains
- Increase or decreased appetite, weight gain or loss
- Anxiety and nervousness, agitation, shaking
- Decreased sexual interest and sexual dysfunction
- Dry mouth
- Muscle and joint pain
- Tingling or numbness in the hands or feet
- Ringing in the ears (tinnitus)
- Itchy rash
- Vision problems
Read the drug information leaflet which should be provided with our medication for more details of potential side effects.
Serotonin syndrome is a response to elevated amounts of serotonin in the body when taking medication that alters body serotonin levels. This primarily occurs when there is an interaction with other medication or overdose, causing an increase in available serotonin. Occasionally, it can occur by taking a normal prescribed dose of an SSRI/SNRI alone.
Symptoms may include tachycardia (fast heart rate), confusion, agitation, muscle twitching or spasms, excessive sweating, shivering, tremor, diarrhoea, lack of coordination, restlessness and fever.
If you are concerned that you are developing serotonin syndrome, seek immediate medical advice.
Who should not take them?
SSRIs should be used with caution in patients with epilepsy, cardiac disease, diabetes mellitus, susceptibility to angle-closure glaucoma, bleeding into the gut.
SSRIs may also impair performance of skilled tasks.
Information regarding who should not take and SNRI is very individual depending on the specific drug. Please read drug information leaflet or discuss with your doctor.
Can I take SSRIs/SNRIs with my other medication?
SSRI/SNRIs can interact with a number of prescribed medication and interactions will vary depending on the type of SSRI/SNRI you are prescribed – speak with your own GP, specialist or community pharmacist.
SSRIs/SNRIs can also interact with over the counter medication such as non-steroidal anti-inflammatory drugs (NSAID) e.g. ibuprofen and aspirin increasing the risk of bleeding into the stomach if taken at the same time.
Drinking alcohol while taking an SSRI/SNRI may increase drowsiness.
Is it safe to take in pregnancy?
The risks of taking SSRIs/SNRIs during pregnancy and while breast feeding remain unknown, therefore manufacturers do not recommend their use.
If the benefits outweigh the risks, SSRIs may be used with extreme caution, and only after advice from your specialist.
Abruptly stopping or reducing a dose of an SSRI/SNRI can cause withdrawal side effects, the symptoms of which may include nervousness, anxiety, irritability, dizziness, sleep problems, difficulty concentrating, headache, nausea and vomiting.
Reducing the dose over a few weeks will reduce the risk of withdrawal side effects. This should be carried out with guidance from your GP or specialist.
*Currently no available medical evidence but generally accepted by experts
Autonomic dysfunction - malfunction of the nervous system in the human body that controls the functions that we do not have to think about eg breathing, heart rate, blood pressure and bladder function
Orthostatic - relating to upright posture
Postural - relating to the position of the body in space
Reuptake inhibitor - Chemicals in the body can be mopped up by the cells that produced them. This process is called ‘reuptake’. If this process is inhibited (blocked) it can result in higher levels of the chemical. A reuptake inhibitor is the chemical that blocks this mopping up process.
Serotonin is a chemical messenger that carries signals between nerve cells to help them communicate with each other
Noradrenalin is a chemical produced by the adrenal gland and nerve cells. One of its actions is to raise blood pressure.
Tachycardia - excessively fast heart rate