SSRI vs. SNRI: Distinctions, Applications, Adverse Effects, and More


The medicines listed on this website are only there to give you knowledge. Just because they are on the list doesn’t mean that anyone will be given them; in the end, treatment decisions are up to the healthcare workers. The medicines on this list are not all of them. Doctors may recommend other drugs, even ones that don’t contain stimulants, depending on the patient’s specific health needs and circumstances.

Two popular kinds of antidepressants used for different mental health issues are SNRIs (selective serotonin-norepinephrine reuptake inhibitors) and SSRIs (selective serotonin reuptake inhibitors). They are a part of the new generation of antidepressants, which improve mental health noticeably and are safer and less likely to cause adverse effects than the older ones.

In spite of their many similarities, they differ significantly in terms of how they function, possible applications, adverse effects, and medication interactions. Which antidepressant class—SSRI or SNRI—might be better for you will be discussed in more depth with your doctor after reading this page, which also provides answers to frequently asked questions regarding these drugs.

SSRI vs. SNRI: Synopsis


The new era of antidepressant drugs began with the introduction of SNRIs into the market in 1993, while the FDA approved SSRIs in 1987. These drugs were initially created to treat depression, but further investigation[1*] has shown that they can also be used to treat a number of other mental and physical illnesses. The following is a list of drugs that fall under each class:

Lexapro (escitalopram)Pristiq (desvenlafaxine)
Citalopram, also known as CelexaCymbalta (duloxetine)
Prozac, or fluoxetineEffexor (venlafaxine)
Acetaminophene (Paxil, Pexeva)Fetsima Levomilnacipran
Zoloft, or sertralineSavella, or Milnacipran
Fluvoxamine, also known as Luvox
Vilazodone (Viibryd)

These new antidepressants are generally more tolerable, have a safer profile, and require less dosage adjustments. Long-term quality of life is enhanced by them as they lessen the symptoms of a variety of psychological issues, such as PTSD, OCD, depression, anxiety disorders, and phobias.

SNRI vs. SSRI: Distinctions and Parallels

Their modes of action are where SNRIs and SSRIs diverge most. SSRIs function by postponing the brain’s nerve cells’ intake of serotonin. Patients have reduced depression symptoms as a result of the brain having access to more serotonin for a longer period of time.

The idea of working with a single, significant modification is likewise applied to SNRIs. They not only prevent the brain from absorbing serotonin, but they also prevent norepinephrine from being reabsorbed.

It is crucial to discuss here how serotonin regulates mood. One of the neurochemicals that is essential to happiness’s[2*] biological functioning is serotonin. Our brain releases dopamine and serotonin, among other “happy hormones and chemicals,” whenever we engage in enjoyable activities. Antidepressants (SSRIs and SNRIs) are thought to balance these “happy hormones” in the brain because it is suspected that depression is caused by a deficiency of serotonin.

Norepinephrine, on the other hand, is essential for the body’s fight-or-flight response in any situation. The body releases more norepinephrine when someone is under a lot of stress for any cause, such as a test, job interview, etc. It affects a person’s mood[3*], motivation, reasoning, sleep, and reasoning. Therefore, it is theorized that depression may also be brought on by this bodily imbalance.

In addition to these functional distinctions, SSRIs and SNRIs share a number of other characteristics, such as safety, effectiveness, and treatment duration. A summary of the key differences between SNRIs and SSRIs is provided in the table below:

CharacteristicSerotonin reuptake inhibitors, or SSRIsSerotonin-norepinephrine reuptake inhibitors, or SNRIs
Method of Actionfocuses on serotonin receptorstargets the receptors for serotonin and norepinephrine.
FDA Approved19871993
Half-lifecomparatively long when compared to other depression medicationsbrief in comparison to other antidepressants
SecurityComparatively safer than earlier generation antidepressants
Effectivenessequivalent to earlier antidepressants
Length of TreatmentLong (generally, six months or more, depending on the state of the patient)
QuantityDepending on the particular drug and the ailment being treated
Priceerratic and dependent on the particular drug
Protection From InsuranceDepending on the insurance company

SNRI vs. SSRI: Applications

Both SNRIs and SSRIs are often used to treat a variety of medical issues as well as a number of mental health disorders. All of these antidepressant classes’ medications are administered for both off-label and alternative label uses.

Below is a summary of the many conditions that SSRIs and SNRIs are used to treat.

FDA-Approved Applications


The FDA recommends using all SSRIs for treating depression, with the exception of fluvoxamine, often known as Luvox, which is used to treat OCD. Sertraline and fluoxetine are two SSRIs that reduce PMDD symptoms in women. PMDD is related to the menstrual cycle.

At the moment, four SNRI medications are licensed to treat depression; the only one that isn’t is milnacipran (Savella), which is approved in the US to treat fibromyalgia. Since these drugs are less successful in treating mild depression, they are often used for moderate to severe cases of depression.

Anxiety Disorder

The FDA has authorized SNRIs and SSRIs for the treatment of panic disorders with or without agoraphobia. The treatment of panic disorders involves the prescription of three medications from the SSRI family: sertraline, fluoxetine, and paroxetine. These medications are particularly beneficial when panic disorder and depression coexist.

Compulsive-obsessive Disorder;

An SSRI called fluvoxamine (Luvox) has a license particularly to treat OCD in humans. Other SSRIs, such as paroxetine, sertraline, and fluoxetine, are also used to treat OCD in addition to fluvoxamine. The dosages used to treat OCD are usually greater than those used to treat depression, and it takes a while for OCD sufferers to have any positive results. By contrast, the FDA has not authorized any SNRI for the treatment of OCD. For this ailment, they are administered off-label, however.

Anxiety Disorders: Social and Generalized

Specific phobias and generalized and social anxiety disorders are treated with certain SSRIs and SNRIs. The diagnosis and severity of a certain condition’s symptoms determine the medication that is best. For generalized anxiety disorder (GAD), the FDA has authorized paroxetine, escitalopram, duloxetine, and venlafaxine; for social anxiety, the recommended medications are sertraline, paroxetine, and extended-release venlafaxine.

Disorder of Posttraumatic Stress

The first-choice method of treating PTSD is therapy. Medication, however, could also be necessary to control symptoms. Doctors often advise SSRIs for this reason since they are good at managing the intrusive and avoidant symptoms of PTSD.

Nervous bulimia

SSRIs are also used to treat anorexia and bulimia, two obsessive illnesses linked to eating behaviors. For this, fluoxetine is used specifically. While psychotherapy is the preferred treatment for these disorders, SSRIs may lessen binge eating and vomiting that are linked to bulimia.

Pain in Neuropathic Nerves

These drugs are used to treat physical disorders in addition to mental health issues. SNRIs are recommended to treat a variety of body nerve problems. Duloxetine[4*] has been licensed by the FDA to treat fibromyalgia (chronic muscle pain) and neuropathic pain linked to diabetes.

Off-Label Applications

When a doctor prescribes a drug that is authorized for one illness but has not yet received FDA approval for another ailment, this is known as off-label usage. The following medical conditions are treated off-label using SSRIs and SNRIs.

Early Fertilization

Because of their anorgasmic effects, SSRIs are given off-label to treat males who ejaculate too soon. Sertraline and fluoxetine are often used for this purpose.


SSRIs are sometimes used to treat migraine headaches that have persisted for a long period, particularly in individuals who also have depression.


Certain SSRIs are used to treat the symptoms of autism spectrum disorders.

Urinary Incontinence Stress

The FDA is now reviewing duloxetine’s application for clearance to treat stress incontinence, which is the most prevalent kind of pee incontinence (inability to retain urine) in women.

Situation FDA-Sanctioned ApplicationOff-label Utilization
Major depressive illness✔️✔️
OCD, or obsessive-compulsive disorder✔️✔️
Disorders of Generalized Anxiety (GAD)✔️✔️
Anxiety Disorder✔️✔️
Disorder of social anxiety (SAD)✔️✔️
PMDD, or premenstrual dysphoric disorder✔️✔️
PTSD, or post-traumatic stress disorder✔️✔️
Anorexia nervosa✔️✔️
Manic Depressive Disorder✔️✔️
diabetic neuropathy✔️
The fibromyalgia✔️
Untimely ejaculation✔️

SNRI vs. SSRI: Interactions and Side Effects

Similar negative effects are experienced by both SSRIs and SNRIs, albeit each individual experiences these side effects differently. The following are the most typical SSRI and SNRI adverse effects:

The following are the most typical SSRI and SNRI adverse effects:

The details of these drugs’ more severe adverse effects are provided below.

Impacts on the Heart

SSRIs and SNRIs have the potential to lengthen QT intervals, which may result in irregular heart rhythms. Individuals who use antipsychotic drugs in addition to antidepressants are particularly at danger. Citalopram has the greatest effect on the QT interval among these drug types.


A study[5*] found that SSRIs and SNRIs may increase the frequency of headaches in individuals.


Seizures[6*] are an uncommon adverse effect that may occur in individuals receiving higher dosages of SSRIs and SNRIs.

Impacts on Blood

Certain blood-related issues, such as the inhibition of platelet aggregation, are brought on by SSRIs and SNRIs. This might put an increased danger of bleeding, particularly in cases of severe injuries. Therefore, while using these drugs with NSAIDs like ibuprofen or blood thinners like aspirin, additional vigilance is advised.

Impacts on Electrolytes and Blood Sugar

Diabetes patients’ blood sugar levels may be lowered by these medications. Therefore, individuals who have problems with their blood sugar should take these drugs with caution. Additionally, they may have an impact on the body’s salt and other electrolyte levels, which might lead to fatigue.

Impacts on Hormones

Prolactin hormone levels, which are mostly linked to breast growth and milk production, may rise in both men and women who use SSRIs. Once therapy is stopped, any breast alterations that may arise while taking these drugs may be reversed.

Beyond-Paradoxical Impacts

Patients with akathisia (inability to stay still), torticollis (neck twisting), dystonia (involuntary movements), bradykinesia (slow movements), and opisthotonos (muscle spasms) may have movement issues as a result of using SSRIs.

Serotonin Syndrome

Serotonin levels in the body may become dangerously high when SSRIs or SNRIs are used with other antidepressants such as lithium, l-tryptophan, or MAOIs. This condition is known as serotonin syndrome[7*] and is characterized by a wide range of symptoms.

The following are the primary characteristics of this disorder:

Common SNRI and SSRI side effectsSerious SNRI and SSRI side effects
mouth dryness
vomiting or feeling queasy
The diarrhea
dysfunctional sexual behavior
increased perspiration
Weight fluctuations (gains or losses)
issues with sleeping
Blunting of emotions
abnormalities in the heartbeat (QT prolongation)
deteriorated judgment, motor, and cognitive
blood issues
Reactions to allergens
Serotonin syndrome
Birth defects
the start of hypomania or mania
difficulties with vision (angle-closure glaucoma)
low salt levels in the blood
problems managing blood sugar
thoughts of suicide

Relationships between Medications.

It is usually safe to combine SSRIs and SNRIs with other prescription drugs. However, before starting antidepressant therapy, you must inform your doctor about all of the drugs you are taking since there are some interactions to be cautious of.

Similar drug interactions occur between SNRIs and SSRIs; the most frequent ones are included in the table below:

MedicineClass of DrugsPotential Interaction between SNRIs and SSRIs

MAOIsSerotonin Syndrome
Lithium-basedagents that are antimanicSerotonin Syndrome
Tryptophan L-α-amino acidSerotonin Syndrome

TCAsTCA toxicity in therapeutic settings


OpioidsReduced ability to effectively manage discomfort
TamoxifenAnti-estrogens without steroidsDiminished efficacy


NSAIDselevated risk of stomach hemorrhage
ClozapineUnusual antipsychoticselevated seizure risk

Anticoagulantsincreased chance of bleeding

See a physician or pharmacist for information on all the potential combinations.

Final Thought

Based on the aforementioned data, it can be concluded that, apart from a few small variations, SSRIs and SNRIs are essentially comparable in terms of their applications, tolerability, effectiveness, and safety profile. Having said that, only a licensed medical professional can determine which drug is appropriate for your situation, and they do so only after carefully reviewing all of your medical records.

FAQs about SNRI vs. SSRI

SSRIs or SNRIs: which is superior?

A number of studies[8*] have been done to assess the effectiveness of SNRIs and SSRIs; however, no clinically significant difference has been seen between the two. Compared to SSRIs, which only target serotonin receptors in the brain, SNRIs target both noradrenaline and serotonin receptors, giving them a modest advantage in their mode of action. However, the doctor’s judgment, which is based on the whole evaluation, together with the patient’s symptoms and diagnosis will determine which drug is prescribed.

Is it possible to combine SNRIs and SSRIs for quicker results?

While both SSRIs and SNRIs are generally safe drugs, there is no proof that taking them together would help you get effects more quickly. Furthermore, in order to prevent any major side effects, it is imperative that you take these prescriptions exactly as prescribed by your doctor.

Is it feasible to convert an SNRI to an SSRI?

The answer is that switching from SNRIs to SSRIs is doable. But, your doctor must take into account a number of factors before altering your treatment plan in this way, including your medication and medical history, how you respond to therapy, any adverse effects, etc. Your doctor may only convert your medication from SNRIs to SSRIs after conducting a thorough examination and ruling out any warning signs.

Which drug is safer, SNRIs or SSRIs?

There are similar adverse effects seen by both SSRIs and SNRIs. There is no medical proof that one of them is more secure than the other. Your medical condition, medical history, and other variables, such as age and genetics, will all influence the drug that is prescribed for your therapy.

Is it okay to use SNRIs or SSRIs while expecting?

It is safe to utilize the majority of SSRIs and SNRIs while pregnant. However, paroxetine (SSRI) should be avoided during pregnancy since it raises the chance of congenital malformations, particularly cardiac problems.

How may an SNRI or SSRI be prescribed?

You must first get an evaluation by a physician to see if you need any of these drugs before you can receive a prescription for SSRIs or SNRIs. This procedure has been greatly simplified by telemedicine. Medication may be given to you from the convenience of your home; this is an easy and affordable procedure that saves you from having to go to the doctor.