What is an SSRI chart?

In this blog we will discuss what an SSRI chart is and what it is used for. 

We will also discuss what SSRIs are, what antidepressants are, their uses, side effects, and the various kinds of antidepressants. 

What is an SSRI chart?

An SSRI chart refers to a flow chart that is commonly referred to in the process of switching antidepressants. 

The charts are created based on clinical research , experience, empirical evidence from trials, and product information from the manufacturers of the drugs. 

These charts are intended as a general guidance for practitioners whilst they work with patients to switch antidepressants. Since it is only a general guideline it is not a concrete strategy that is compulsory for each case.

In some cases, it is necessary to modify the process of gradual switching recommended by these charts based on the patient, the history of the illness, and other interaction variables such as clinical progress of the client. 

When switching antidepressant drugs such as SSRIs, the strategy used includes one of the following:

  • Direct switch which involves stopping the drug abruptly and then starting another one immediately, which is not really recommended by most physicians
  • Taper and Switch immediately which involves gradual tapering of the first drug by reducing the dosage gradually followed by an immediate continuation with the new drug.
  • Taper and switch after washout which involves gradually tapering of the first drug as the dosage reduces, followed by a washout period where the drug is removed from the body over time, then constitution of treatment with a new drug. 
  • Cross tapering where the first drug is tapered as the drug dosage reduces over one to two weeks and simultaneously the dosage of the new drug is increased. 

Whichever strategy is used, the doctor and the patient closely monitor symptoms and side effects to determine tapering and success of the switch in treatment. 

It has to be mentioned that all switches from one antidepressant to another may result in serious complications due to side effects which is why these SSRI charts are used as guidelines for the practitioner. 

While the chart serves as a guideline, in appropriate circumstances expert prescribers may use other strategies that are justified by harm–benefit considerations for the patient. 

Below we provide you with a sample of an SSRI chart from the British Columbia Guidelines for switching antidepressants:

What is an SSRI chart?

What is an SSRI?

SSRIs are the most commonly prescribed antidepressants because of their high levels of efficacy and low number of side effects. 

These drugs help to increase levels of serotonin in the brain by inhibiting reuptake of these chemicals by blocking the receptors. 

As SSRIs affect the levels of serotonin and not other neurotransmitters, they are referred to as “selective.”

The use of this class of antidepressants commonly involve a few side effects such as nausea, vomiting, diarrhea, sexual dysfunction, headache, weight gain, anxiety, dizziness, dry mouth, and trouble sleeping.

According to Andrew Chu and Roopma Wadhwa’s article on SSRIs,  SSRI are not only used for the treatment of depression but also for:

  • obsessive-compulsive disorder (OCD)
  • generalised anxiety disorder
  • panic disorder
  • bulimia
  • bipolar depression
  • post-traumatic stress disorder (PTSD)
  • premenstrual dysphoric disorder (PMDD)
  • anxiety

As well as for off-label uses for disorders like:

  • fibromyalgia
  • binge eating disorder
  • body dysmorphic disorder
  • autism

What are the side effects of SSRIs ?

Common side effects of Antidepressants include:

  • Gastrointestinal symptoms such as indigestion, diarrhoea, constipation, loss of appetite
  • Headache, dizziness, dry mouth, sweating
  • Agitation, shakiness, nervous feeling
  • Palpitations, fast heartbeat
  • Blurry vision
  • Unexpected weight loss or weight gain
  • Sexual dysfunction and low libido
  • Insomnia

What are antidepressants?

Antidepressants are medications that were first developed in the 1950s that are used to help treat symptoms of depression, social anxiety disorder, anxiety disorders, seasonal affective disorder, and dysthymia, or mild chronic depression, as well as other conditions.

Antidepressants work to correct chemical imbalances in the brain- chemicals known as neurotransmitters that are responsible for changes in mood, behaviour, and emotions. 

By correcting and balancing the levels of these chemicals in the brain in various ways, these medicines can help improve your mood, bring positive changes related to various symptoms such as focus and concentration, sleep, appetite etc.

Antidepressants are of different classes or different types depending on their target and the process by which they help balance neurochemical levels in the brain. 

The different classes of antidepressants are as follows:

Serotonin norepinephrine reuptake inhibitors (SNRIs) 

This particular medication works by blocking the reabsorption of the neurotransmitters serotonin and norepinephrine in the brain so as to increase the levels of these neurotransmitters. 

The difference between SSRIs and SNRIs is that SNRI is not selective and may influence the levels of other neurotransmitters. 

The common side effects of SSRIs include nausea, dizziness, and sweating as well as sexual dysfunction. Other less serious side effects include tiredness, constipation, insomnia, anxiety, headache, and loss of appetite.

Significant and serious side effects also include abnormal bleeding when used wiht other drugs and blood thinners as well as increase in the rates and the risk of suicidal thoughts or behavior in children, adolescents, and young adults (18 to 24 years of age).

Some SNRIs should also not be used by people who are affected with uncontrolled narrow angle or angle-closure glaucoma.

Atypical antidepressants

This type of drugs do not fit into any of the other classes of antidepressants and each drug under this category has a unique mechanism with which it affects  the body. 

However, atypical antidepressants also affect the levels of dopamine, serotonin, and norepinephrine in the brain. 

Since medications in this class are all unique in their effect on the body, their side effects also vary. Some common side effects include dry mouth, constipation, dizziness, and lightheadedness.

Some of these drugs can cause abnormal heart rhythms that can be life threatening as well as cause a rare sexual disorder that involves painful and prolonged erection in males.

Some of these drugs are also not recommended in patients with active liver disease and it can increase the likelyhood of Suicidal thoughts or behavior. 

According to a systematic review on Antidepressants used for the primary care for adult patients, the first generation antidepressants include:

  • Tricyclic antidepressants (TCAs) 
  • Monoamine oxidase inhibitors (MAOIs)

Tricyclic antidepressants (TCAs) 

Tricyclic antidepressants are drugs that block the reabsorption of Serotonin and norepinephrine in the brain and they were the first approved drugs for depression; it is part of the first generation antidepressants that were developed and used during the 1950s. 

According to Jennifer Fink, a writer for Healthline, TCAs that are still being used and are currently available include:

  • amitriptyline
  • amoxapine
  • desipramine (Norpramin)
  • doxepin
  • imipramine (Tofranil)
  • maprotiline
  • nortriptyline (Pamelor)
  • protriptyline (Vivactil)
  • trimipramine (Surmontil)

With the advent of other more effective antidepressants with lesser or milder side effects, medical providers and clinicians prescribe tricyclic antidepressants as a last resort treatment after other drugs have failed to relieve depression. 

This particular class of antidepressant helps to improve symptoms of depression by retaining higher levels of serotonin and norepinephrine in the  brain thus, helping elevate your mood.

It is not only used for depression but also has many off-label uses for treatment of conditions such as obsessive compulsive disorder (OCD) and lower doses can be used for the treatment of migraines and to treat chronic pain. 

One of the major reasons why Tricyclic Antidepressants are no longer considered primacy treatments is because of the high number of adverse effects it has on the body. Because it is not selective, it can impact several neurotransmitters in the brain leading to many side effects.

Monoamine oxidase inhibitors (MAOIs) 

MAOIs is another first generation class of antidepressants which were introduced around the same time as tricyclic drugs- during the 1950s. 

Monoamine oxidase inhibitors are drugs that work by blocking or inhibiting the activity of monoamine oxidase which is crucial in the breakdown of norepinephrine, serotonin, and dopamine in the brain and other parts of the body. 

To understand how this particular drug works is to understand what Monoamine oxidase is. 

Monoamine oxidase is a type of enzyme that helps the functioning of neurons- is what regulates the firing of the neurons throughout one’s body (Healthline).

Because of the high amount of drug and food interactions and servois side effects of MAOIs, it is not a first choice drug intervention. However, according to Brian Kerns for Healthline, there are some approved MAOIs:

  • Isocarboxazid (Marplan)
  • Phenelzine (Nardil)
  • Tranylcypromine (Parnate)
  • Selegiline (Emsam, Atapryl, Carbex, Eldepryl, Zelapar), which is a newer type of MAOI.

This drug is not a primary option that many physicians prescribe because it has many drug and food interactions and also causes significant side effects. As a result, this class of drug has been replaced by newer antidepressants that are safer and cause fewer side effects.


In this blog we have discussed what an SSRI chart is and what it is used for. 

We have also discussed what SSRIs are, what antidepressants are, it’s uses, side effects, and the various kinds of antidepressants. 

FAQ related to SSRI chart

Which SSRIs are the best?

It has been observed that citalopram appears to be the best-tolerated SSRI, followed by fluoxetine, sertraline, paroxetine, and fluvoxamine. 

Which is the SSRI for anxiety?

The only SSRI that is currently FDA-approved for treatment of anxiety is sertraline (Zoloft) and immediate- and extended-release paroxetine (Paxil, Paxil CR). 

What are the top 3 antidepressants?

The top most commonly prescribed ones include:

  • Fluoxetine.
  • Citalopram.
  • Sertraline.

How much of an SSRI is lethal?

There is a lack of conclusive research as to how much ssri is lethal. It is speculated that the amount is between 520 mg of fluoxetine to 8 grams of the same drug. However, this amount might change depending on what form of SSRI is being taken. 


Chu A, Wadhwa R. Selective Serotonin Reuptake Inhibitors. [Updated 2022 Jan 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554406/

Selective Serotonin Reuptake Inhibitors (SSRIs): What to Know. Healthline. Retrieved on 30th March 2022. https://www.healthline.com/health/depression/selective-serotonin-reuptake-inhibitors-ssris

O’Connor EA, Whitlock EP, Gaynes B, et al. Screening for Depression in Adults and Older Adults in Primary Care: An Updated Systematic Review [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2009 Dec. (Evidence Syntheses, No. 75.) Table 2, List of antidepressants and their categorizations. Available from: https://www.ncbi.nlm.nih.gov/books/NBK36406/table/ch1.t2/

Cherney.L.What Medications Help Treat Depression?. Healthline. Retrieved on 30th March 2022.  https://www.healthline.com/health/depression/medication-list#atypical-medications

Nordqvist.C. All about antidepressants. Medicalnewstoday. Retrieved on 30th March 2022. https://www.medicalnewstoday.com/articles/248320#uses

Fink.J.Tricyclic Antidepressants. Healthline. Retrieved on 30th March 2022. https://www.healthline.com/health/depression/tricyclic-antidepressants-tcas

Krans.B. What Are MAO Inhibitors? Healthline.  Retrieved on 30th March 2022. https://www.healthline.com/health/depression/what-are-mao-inhibitors#how-maois-work