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Venlafaxine - Uses, Dosage, Side Effects, Drug Warnings, and Precautions

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Venlafaxine - Uses, Dosage, Side Effects, Drug Warnings, and Precautions

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Venlafaxine is an oral prescription drug that is used to treat depression and social anxiety disorder (SAD). Learn more about Venlafaxine, its uses, dosage, side effects, drug warnings, and precautions.

Medically reviewed by

Dr. Sai Naveen Singagari

Published At October 12, 2021
Reviewed AtJanuary 22, 2024


Venlafaxine is an oral prescription drug that comes both as a tablet and capsule. It comes in two forms:

  • Immediate-release form.

  • Extended-release form.

Venlafaxine has to be taken exactly as directed. This drug, when taken as required, helps people recover from depression and has fewer side effects than the other antidepressants. Venlafaxine cannot be given to children. It is generally prescribed for adults who are above the age of 18 years. People with heart problems should consult a doctor before taking this drug as it can increase the heartbeat.

Drug Group:

Venlafaxine is an antidepressant belonging to a group of medications called the Selective Serotonin and Norepinephrine Reuptake Inhibitors (SSNRIs). The other drugs belonging to this group are the following:

What Is Venlafaxine Used For?

Venlafaxine is an oral prescription antidepressant drug that is used to treat the following conditions:

The other conditions that can be treated using this medication are:

  • Hot flashes, the sudden extreme feeling of heat and sweating, especially in menopausal women.

Venlafaxine can be prescribed to treat other conditions as well. So talk to the doctor about the risks and precautions of using this medication to treat the condition.

How Does Venlafaxine Work?

Venlafaxine, like any other Selective Serotonin Norepinephrine Reuptake Inhibitors (SSNRIs), works by increasing the amount of serotonin and norepinephrine, the chemical substances that help to maintain the mental balance. These drugs block the reabsorption of the neurotransmitters serotonin and norepinephrine in the brain.

How Should Venlafaxine Be Used?

There are certain things that need to be followed before or while taking Venlafaxine. It includes:

  • Try taking Venlafaxine with food.

  • You can cut the immediate-release tablet but do not try cutting the extended-release tablet.

  • Do not crush the tablet.

  • Take Venlafaxine once or twice daily as directed by the doctor.

  • Try to stick to the same time every day.

  • In case you find it hard to fall asleep in the night after taking the drug, take the drug in the morning.

The Onset of Action:

Venlafaxine takes around 4 to 6 weeks to work. In most conditions, doctors recommend taking Venlafaxine for six months to one year until the patient’s condition is improved.

Can Venlafaxine Be Taken For A Long Period of Time?

Generally, Venlafaxine is considered safe to take for a long period of time. Certain people may have few sexual side effects like problems getting an erection or low sexual desire. Other than these sexual side effects, there are not many lasting harmful adverse effects of this drug.

What Is the Dosage of Venlafaxine?

The dosage, drug form, and the duration of how long you should take the drug depend on the age, the condition for which the drug is prescribed, the severity of the condition, and overall general health.

dosage of drug

What If I Forget To Take a Dose?

If you forget to take the scheduled dose, then take the next dose as scheduled if it is a few hours before the next dose. Take only one dose at a time. Do not take double doses to catch up with the forgotten dose.

What Will Happen If I Take Too Much?

Venlafaxine should be taken as directed. When an overdose of Venlafaxine is taken, it can result in dangerous levels of the drug in the body. It can even be life-threatening. There can be certain symptoms that can be commonly seen when Venlafaxine is taken in overdose. It includes:

  • Increased heart rate.

  • Sleepiness.

  • Seizures.

  • Low blood pressure.

  • Muscle pain.

  • Dizziness.

  • Pupils become enlarged.

  • Changes in the heart rhythm.

What Are the Drug Warnings of Venlafaxine?

There are certain drug warnings for Venlafaxine. People with these conditions should avoid taking Venlafaxine:

  • People who had a previous history of allergic reactions to taking Venlafaxine.

  • People with liver disease.

  • People with a kidney disorder.

  • People with issues related to the heart.

  • People having thyroid problems, especially hyperthyroidism.

  • People with a previous history of seizures.

  • People with a history of glaucoma.

  • Pregnant women.

  • Children.

Can Venlafaxine Be Prescribed for Pregnant Women?

Venlafaxine is generally not prescribed for pregnant women as it belongs to the C category. Certain studies have shown that Venlafaxine when taken during pregnancy, can create adverse effects in the developing fetus.

Is It Safe To Take Venlafaxine During Breastfeeding?

Venlafaxine can pass into breast milk and can cause side effects in the child who is breastfed. So, while breastfeeding it is always advised to talk to a doctor before taking the drug.

What Are the Side Effects of Venlafaxine?

Some of the common side effects of Venlafaxine are:

  • Strange and unusual dreams.

  • Decreased desire for sex.

  • Trouble having an orgasm.

  • Not being able to get an erection.

  • Loss of appetite.

  • Constipation.

  • Dry mouth.

  • Fatigue.

  • Nausea and vomiting.

  • Finding it hard to sleep.

  • Dizziness.

  • Sweating.

  • Blurred vision.

  • Feeling anxious.

  • Raised heart rate.

  • Headache.

  • Tremors or chills.

The symptoms usually go away if they are mild. But if the symptoms last for long, then a doctor has to be consulted immediately.

There are some serious side effects such as:

  • Having suicidal thoughts.

  • Aggressive or violent behavior.

  • Worsening depression.

  • Anger and restlessness.

  • Serotonin syndrome.

The symptoms of serotonin syndrome are:

  • Hallucinations.

  • Coma.

  • Agitation.

  • Unusual changes in mental status.

  • High blood pressure.

  • Mania.

  • Seizures.

  • Problems with the eye.

  • Hyponatremia (low sodium levels).

  • Frequent nose bleeds.

  • Dark-colored stools.

What Are the Interactions of Venlafaxine?

Venlafaxine interacts with certain medications when taken along. Such medications include:

  • Monoamine oxidase inhibitors (MAOIs) such as Linezolid, Methylene Blue.

  • Drugs that are taken for weight loss, such as Phentermine.

These drugs should not be taken with Venlafaxine.

Drugs that can increase the side effects when taken together are:

  • Cimetidine.

  • Haloperidol.

  • Warfarin.

  • Anti-inflammatory drugs like Aspirin, Ibuprofen, Naproxen, and Ketoprofen.

  • Ritonavir.

  • Clarithromycin.

  • Ketoconazole.

  • Zolpidem.

  • Lorazepam.

  • Diphenhydramine.

  • Fluoxetine.

  • Paroxetine.

  • Citalopram.

  • Duloxetine.

  • Drugs used to treat migraines are known as Triptans. The drugs that belong to this group are Sumatriptan, Zolmitriptan.

Drugs, when taken along with Venlafaxine that can lower the effect, are the following:

  • Metoprolol.

What Are the Common Brand Names of Venlafaxine?

The common brand names of Venlafaxine are:

  • Effexor.

  • Effexor-XR.

Frequently Asked Questions


What Are the Common Side Effects of Venlafaxine?

The common side effects of Venlafaxine are,
- Headaches.
- Feeling sick.
- Dry mouth.
- Sweating.
- Trouble sleeping.
- Feeling sleepy.
- Constipation.
- Feeling dizzy.


Does Venlafaxine Calm You Down?

Venlafaxine helps to feel calm and relaxed. Venlafaxine could take some time to show its full effect. This effect reduces the behavior problem.


Can You Drink Coffee While Taking Venlafaxine?

Caffeine has shown no significant blockage of a painful or injurious stimulus by sensory neurons at the applied dose, but it significantly antagonizes the antinociceptive effect of Venlafaxine at 30 min.


What Are the Long-Term Effects of Taking Venlafaxine?

There are no problems associated with the long-term use of Venlafaxine. It is a completely safe and effective medication when directed by the doctor's advice.


What Drugs Should Not Be Taken with Venlafaxine?

Venlafaxine causes a serious condition known as serotonin syndrome when this medication is taken together with certain medicines. Avoid using Venlafaxine with,
- Fentanyl (Abstral, Duragesic).
- Buspirone (Buspar).
- Linezolid (Zyvox).
- Methylene blue injection.
- Lithium (Eskalith, Lithobid).
- Tryptophan.


What Does Venlafaxine Do to the Brain?

Venlafaxine is an antidepressant known as SNRIs or serotonin and noradrenaline reuptake inhibitors. These medicines work by inducing the levels of mood-enhancing chemicals named serotonin and noradrenaline in the brain.


Does Venlafaxine Increase Body Weight?

Venlafaxine will make us feel less hungry than usual, so it will make us lose weight while starting to take this medication. Some people may gain weight, and so when there are problems with weight while taking Venlafaxine, talk to the health care specialist or pharmacist.


Does Venlafaxine Make You Tired?

Venlafaxine oral tablets cause drowsiness, and it also affects the ability to make decisions, react quickly, or think clearly. It would be best not to use heavy machinery, drive, or do things that require alertness until the person functions normally. Apart from this, there are other side effects caused by Venlafaxine.


What Disorders Does Venlafaxine Treat?

The antidepressant Venlafaxine medication works by depressing the brain. It is approved for the treatment of,
- Generalized anxiety disorder (GAD).
- Major depressive disorder (MDD).
- Panic disorder.
- Social anxiety disorder (social phobia).


When Should I Take Venlafaxine?

Venlafaxine 75 mg extended-release capsules or tablets are taken once a day. It can be taken at any time as long as you start to take this medicine at the same time every day. While taking this medicine, if there is trouble sleeping, it is best to take it in the morning.


Does Venlafaxine Cause Memory Loss?

Venlafaxine does not influence cognitive functions like,
- Memory.
- Choice reaction.
- Subjective mood.
- Psychomotor performance.
But it is said that people taking selective serotonin reuptake inhibitors (Venlafaxine) experienced a decline in memory function within 2 months of starting treatment.


What Painkillers Can I Take with Venlafaxine?

Painkillers like Paracetamol can be taken with Venlafaxine. Anti-inflammatory painkillers such as Aspirin, Celecoxib, Ibuprofen, Naproxen, or Diclofenac should be taken with caution when it is taken with Venlafaxine, as they may increase the chances of bleeding.
Dr. Sai Naveen Singagari
Dr. Sai Naveen Singagari



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