Venlafaxine Mechanism Of Action: What Does Effexor Do?

Last Updated: December 19, 2019

Authored by Nena Messina, Ph.D.

Venlafaxine is a novel antidepressant drug, each tablet containing venlafaxine hydrochloride (which can be the equivalent of 25 mg, 37.5 mg, 50 mg, 75 mg, or 100 mg venlafaxine). The inactive Effexor ingredients are sodium starch glycolate, magnesium stearate, lactose, iron oxides, and cellulose.

Venlafaxine structure is 1-[2-(dimethylamino)-1-(4 methoxyphenyl)ethyl]cyclohexanol and consists of the racemic mixture, which is made of two enantiomers. Venlafaxine mechanism of action is related to tramadol and tapentadol opioids.

According to the Effexor XR classification, this version has the same chemical structure as the normal venlafaxine. How does Effexor work? The difference is that it takes longer for the first one to distribute the Effexor’s release in the gastrointestinal tract leading to a lower peak plasma concentration.

What Is Venlafaxine Mechanism Of Action?

What does Effexor do? Venlafaxine (Effexor) is an SSRI which blocks the transporters responsible for the reuptake of norepinephrine and serotonin. The FDA approved Effexor for use in the management of the panic disorder, major depressive disorder (MDD), social anxiety disorder, and generalized anxiety disorder (GAD).

How Long Does It Take For Venlafaxine To Work?

Full effects of the venlafaxine immediate-release tablets are seen two to three hours after ingestion if it is taken at regular intervals. The effects of venlafaxine extended-release are felt five to nine hours after ingestion, with regular dosages. Both drug options have the same body elimination rate.

The first effects on depression of Effexor MOA are seen two to four weeks when the patient should experience a decrease in depressive symptoms. The drug reaches its maximum efficacy after eight weeks. Some patients might experience an increase in anxiety at the beginning of the treatment, a possible result of the drug’s mechanism of action, which will start to decrease in the following weeks. Effexor pills should be taken for several months, to avoid depression relapse. The treatment for depression usually lasts for six months and generalized anxiety disorder for around 18 months.

effexor boosts energy level

How To Tell If Effexor Is Working?

If the recommended dosage of Effexor is the right one, the patient should feel an improvement in energy levels, mood, and interest in daily living. Feeling of anxiety and fear or unwanted thoughts should decrease, as well as the panic attacks. The patient should note that the treatment must not be stopped even if the depression improves.

The two main signs that the Effexor MOA takes place are the decrease or lack of thoughts of self-harm and teariness. Later on, the patient will be more tolerant; little things will not irritate them anymore and will have more sense of enjoyment.

Can Effexor Work Immediately?

Taking more pills than recommended or more often will not make the drug work faster as expected but would increase the possibility of an overdose.

What does venlafaxine do in large doses? There are people who abuse venlafaxine because in large doses it mimics the high given by amphetamines. Although Effexor is not considered an addictive drug, it can be psychologically addictive to people who abuse it to elevate their mood or get the needed high. People abusing the drug will ingest more tablets and more frequently than prescribed by the doctor, many times buying the pills from the internet, from the street, from illegitimate pharmacies or from friends who get the pills on prescription.

why effexor not working

How To Tell If Effexor Is Not Working?

There are several signs that could show the patient if Effexor stopped working or if it’s not working at all:

  • No relief observed between four to six weeks after the beginning of the treatment. If no improvement in symptoms is seen by three months, the patient should address the doctor.
  • Mood swings, such as extreme changes in emotions, both negative and positive, might be a sign of Effexor not working, and the patient might need to change the dosage or the medication.
  • The depression gets worse. This situation can be seen when the patient takes other medication simultaneously causing the antidepressant to act differently, making the symptoms worse.
  • The drug’s side effects are too much for the patient. Effexor symptoms include nausea, vomiting, sleep problems, dizziness, changes in weight, drowsiness, blurred vision or headaches, which can be very intense in some patients.
  • A sudden increase in energy combined with the blues. An increase in energy is a sign that Effexor is working, but if the patient still has depression symptoms, it can lead to a bad combination, which can make the individual act out or experience an increased risk for suicide. This is a sign of Effexor not working as it should, and the patient needs to address the doctor right away.
  • The symptoms have improved, but the patient still does not feel like themselves. The treatment might offer some relief, but not the expected one.

Because the Effexor XR half-life is around 15 hours, patients should adhere to the prescribed treatment plan. Even a single dose missed can lead to withdrawal symptoms, and in some cases, a need for Effexor withdrawal symptoms treatment.

What To Do To Benefit The Most From Effexor?

There are some tips that can make the patient increase the chances of the drug working and taking full advantage of Effexor mechanism of action:

  • Take the medication with food.
  • Do not crush, break or chew the tablet, swallow it whole.
  • Avoid alcohol during the treatment.
  • Do not stop Effexor cold turkey.
  • Be alert for any changes that might come up, such as depressed mood, agitation, hallucinations, dizziness, increased heart rate, or suicidal thoughts. Immediately seek medical attention.

The misuse of Effexor by taking it more often than recommended or not respecting the dosage can lead to substance use disorders that require timely treatment. The patient should be correctly informed about this danger before prescribing this drug to them. There are numerous specialized drug addiction rehab centers that provide help to patients who have developed an addiction.

Page Sources

  1. Song JH, Yu BH, Lee D, Yoon SC, Jeon HJ. Uncontrolled self-medication with venlafaxine in a patient with major depressive disorder. Psychiatry Investigation. 2011; 8(1): 74–76. doi:10.4306/pi.2011.8.1.74.

Published on: November 29th, 2019

Updated on: December 19th, 2019

About Author

Nena Messina, Ph.D.

Nena Messina is a specialist in drug-related domestic violence. She devoted her life to the study of the connection between crime, mental health, and substance abuse. Apart from her work as management at addiction center, Nena regularly takes part in the educational program as a lecturer.


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