Healthy Living

What Is Venlafaxine: Uses, Side Effects, Dosage, and Interactions

What Is Venlafaxine: Uses, Side Effects, Dosage, and Interactions

Generic Name: Venlafaxine

Brand Name(s): Effexor, Effexor XR

Introduction

Venlafaxine belongs to the class of selective serotonin and norepinephrine reuptake inhibitors (SNRIs), which are used for the treatment of anxiety, panic disorder, and major depressive disorder. This medication works by increasing the amounts of chemicals called serotonin and norepinephrine in the brain. These brain chemicals are vital when it comes to maintaining mental balance as well as improve the symptoms of depression and anxiety. 

Important Notes

Individuals who are being treated with methylene blue injection or have an uncontrolled narrow-angle glaucoma should not use venlafaxine. Venlafaxine should not also be used 1 week before or two weeks after using MAO inhibitors, which include:

  • Linezolid
  • Isocarboxazid
  • Methylene blue injection
  • Rasagiline
  • Selegiline
  • Phenelzine
  • Tranylcypromine

According to clinical studies, a small number of young people (children up to 24 years old), who take antidepressants for the first time became suicidal or having thoughts of killing or trying to harm oneself. Young people who take antidepressants for the treatment of their depression or other types of mental illnesses are more likely to experience suicidal thoughts than those who do not use antidepressants to treat their mental condition. 

Normally, individuals who are younger than 18 years old should not be allowed to take venlafaxine. However, in some cases, healthcare providers may recommend venlafaxine as the most suitable medication for the treatment of a child's condition. 

Those who are over 24 years old should also be aware that they may also experience unexpected mental changes when they take venlafaxine or other antidepressants. Individuals may become suicidal at the start of treatment and whenever there is a change in their dosage. 

Patients, their family, or caregiver should immediately notify the doctor if any of the following symptoms are observed:

  • A worsening depression
  • Suicidal thoughts (planning, trying, or thinking about killing or harming oneself)
  • Panic attacks
  • Extreme worry
  • Agitation
  • Severe restlessness
  • Aggressiveness
  • Irritability
  • Frenzied, abnormally excited mood
  • Insomnia (difficulty falling asleep or staying asleep)
  • Impulsivity

Do not stop using venlafaxine without first speaking to your healthcare provider. 

Usage

Venlafaxine can be orally taken in the form of tablets or extended-release capsules. The tablet form is usually taken with food 2-3 times a day. The extended-release capsule, on the other hand, can be taken once a day with food either in the morning or evening. 

Follow your doctor's specific instructions on how to take venlafaxine. You can also read the prescription label and follow the given instructions. If there are some parts you do not understand, you can ask your doctor or pharmacist about it.

It is usually recommended to take venlafaxine at the same time every day. Avoid taking more or less of this medication than prescribed. The extended-release capsule must be swallowed whole, and should not be chewed, crushed, split, or dissolved in water. 

If the extended-release capsule cannot be swallowed, the capsule may be opened and its contents may be sprinkled on a spoonful of applesauce. Immediately swallow the mixture without chewing with a glass of water to ensure that all of the medication is swallowed. 

Inform your healthcare provider about the effects of venlafaxine on you, so the doctor will be able to properly adjust the dosage of your medication. In most cases, a low dose of venlafaxine is initially given and then gradually increased depending on your condition. 

It is important to note that venlafaxine does not cure depression, but only controls it. It may take up to eight weeks of usage or even longer before noticing any improvements in your symptoms. Even if you already feel well, do not stop taking this medication. Abruptly stopping venlafaxine may cause the following withdrawal symptoms:

  • Anxiety
  • Agitation
  • Irritability
  • Sad mood
  • Frenzied, abnormally excited mood
  • Confusion
  • Nightmares
  • Insomnia (difficulty falling asleep or staying asleep)
  • Lack of coordination
  • Electric shock-like feeling or sensation
  • Ringing in the ears
  • Seizures
  • Sweating
  • Dry mouth
  • Loss of appetite
  • Nausea and vomiting
  • Diarrhea

Immediately inform your doctor if you experience any of the above symptoms while gradually tapering off venlafaxine or soon after stopping the medication. 

Other Uses 

Venlafaxine is sometimes used for the treatment of hot flashes in menopausal women and in women taking medications for the treatment of breast cancer. Speak with your doctor or pharmacist about the risks of venlafaxine use for the treatment of your condition. 

Dosage

Adult Dose for Depression

The daily dosage of venlafaxine immediate release may be taken 2-3 times a day.

  • Initial Dose: 37.5 mg taken orally two times a day or 25 mg taken orally three times a day. 
  • Maintenance Dose: A dosage increase can be done with daily increments of 75 mg at an interval of four days.
  • Maximum Dose (outpatients with moderate depression): 225 mg taken orally once a day.
  • Maximum Dose (inpatients with severe depression): 375 mg taken orally once a day.

Extended-release capsule for the treatment of major depressive disorder (MDD):

  • Initial Dose: 75 mg taken orally once a day.
  • Maintenance Dose: A dosage increase can be done with daily increments of 75 mg at an interval of four days.
  • Maximum Dose (outpatients with moderate depression): 225 mg taken orally once a day.
  • Maximum Dose (inpatients with severe depression): 375 mg taken orally once a day.

Adult Dose for Anxiety

Extended-release capsule for the treatment of generalized anxiety disorder (GAD) and social anxiety disorder (SAD):

  • Initial Dose: 75 mg taken orally once a day.
  • Maintenance Dose: A dosage increase can be done with daily increments of 75 mg at an interval of four days. 
  • Maximum Dose: 225 mg taken orally once a day.

Adult Dose for Panic Disorder

Extended-release capsule for the treatment of panic disorder (PD) with or without agoraphobia:

  • Initial Dose: 37.5 mg taken orally once a day. 
  • Maintenance Dose: A dosage increase can be done with daily increments of 75 mg at one week interval.  
  • Maximum Dose: 225 mg taken orally once day. 

Side Effects

The common side effects of venlafaxine may include:

  • Vision changes
  • Nausea and vomiting
  • Diarrhea
  • Changes in weight or appetite
  • Dry mouth
  • Yawning
  • Headache
  • Dizziness
  • Nervousness
  • Anxiety
  • Tremors
  • Shaking
  • Tachycardia (fast heartbeat)
  • Insomnia
  • Strange dreams
  • Feeling tired
  • Increased sweating
  • Low libido
  • Impotence
  • Trouble reaching an orgasm

Seek immediate medical attention if you notice any signs and symptoms of an allergic reaction after taking venlafaxine:

  • Hives
  • Skin rash
  • Difficulty breathing
  • Swelling of the face, throat, tongue, or lips

Inform your doctor if you develop new or worsening symptoms, which include:

  • Panic attacks
  • Anxiety
  • Impulsivity
  • Irritability
  • Agitation
  • Aggressiveness
  • Restlessness
  • Mood changes
  • Behavior changes
  • Severe depression
  • Suicidal thoughts
  • Trouble sleeping
  • Mentally or physically hyperactive

Call your doctor right away if you have any of the following symptoms:

  • Vision problems (eye pain or swelling, tunnel vision, blurred vision, or visual halos around lights)
  • Bleeding or easy bruising (bleeding gums or nosebleeds)
  • Presence of blood in urine or stool
  • Hemoptysis or coughing up blood
  • Chest tightness
  • Difficulty breathing
  • Seizures
  • Hyponatremia (low sodium levels in the body), which causes confusion, headache, vomiting, hallucinations, slow breathing, severe weakness, slurred speech, or feeling unsteady
  • Severe nervous system reactions such as confusion, irregular heartbeat, tremors, fainting, sweating, stiff muscles, and high fever

Seek emergency medical help right away if you experience the following symptoms of serotonin syndrome:

  • Hallucinations
  • Agitation
  • Shivering
  • Sweating
  • Fever
  • Tachycardia (fast heart rate)
  • Twitching
  • Loss of coordination
  • Muscle stiffness
  • Nausea and vomiting
  • Diarrhea

Other side effects may occur with this medication. Speak with your doctor for more information about the side effects of venlafaxine. 

Drug Interactions

Taking this medication with other drugs that can cause drowsiness can worsen its side effects. Inform your doctor if you are taking other medications, such as narcotic pain medications, sleeping pills, muscle relaxants, anti-anxiety drugs, antidepressants, and anticonvulsants. 

Other drugs that can interact with venlafaxine are:

  • Tramadol
  • Cimetidine
  • St. John's wort
  • Tryptophan 
  • Blood thinners (warfarin, Coumadin, Jantoven)
  • Buspirone
  • Lithium
  • Migraine medications (sumatriptan, zolmitriptan)

Key Takeaways

  • Venlafaxine is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) used for the treatment of anxiety, panic disorder, and major depressive disorder.
  • This medication works by increasing the amounts of chemicals called serotonin and norepinephrine in the brain.
  • A small number of young people (children up to 24 years old), who take antidepressants for the first time tend to become suicidal or having thoughts of killing or trying to harm oneself.