Venlafaxine
Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) for depression, generalized anxiety, social anxiety and panic disorder
📊 Quick Facts About Venlafaxine
💡 Key Takeaways About Venlafaxine
- Dual mechanism of action: Venlafaxine inhibits reuptake of both serotonin and norepinephrine, making it effective when SSRIs alone are insufficient
- Takes time to work: Full therapeutic effects typically develop after 4–6 weeks; do not stop treatment prematurely
- Never stop abruptly: Venlafaxine has particularly pronounced withdrawal symptoms; dose must be tapered very gradually over weeks or months
- Blood pressure monitoring: Venlafaxine can cause dose-dependent increases in blood pressure; regular monitoring is recommended
- Monitor young adults: Increased risk of suicidal thoughts in patients under 25 during the first weeks of treatment
What Is Venlafaxine and What Is It Used For?
Venlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant used to treat major depressive disorder, generalized anxiety disorder (GAD), social anxiety disorder (social phobia), and panic disorder. It works by increasing the levels of both serotonin and norepinephrine in the brain, helping to restore chemical balance and improve mood, anxiety, and emotional well-being.
Venlafaxine belongs to a group of medications known as SNRIs (serotonin-norepinephrine reuptake inhibitors). Unlike SSRIs, which only affect serotonin, venlafaxine inhibits the reuptake of both serotonin and norepinephrine at the presynaptic neuronal membrane. At lower therapeutic doses (75 mg/day), serotonin reuptake inhibition predominates; as the dose increases, norepinephrine reuptake inhibition becomes increasingly important. At very high doses, there is also a weak inhibitory effect on dopamine reuptake. This dose-dependent pharmacological profile is unique among antidepressants and explains why higher doses may be more effective for certain patients.
The exact mechanism by which venlafaxine exerts its antidepressant and anxiolytic effects is not fully understood, but it is believed to be related to the enhancement of serotonergic and noradrenergic neurotransmission in the central nervous system. Venlafaxine has no significant affinity for muscarinic cholinergic, histaminergic H1, or alpha-1-adrenergic receptors, which accounts for its relatively favorable side effect profile compared to older tricyclic antidepressants.
Venlafaxine is available under numerous brand names worldwide, including Efexor Depot, Venlafaxin Actavis, Venlafaxin 1A Farma, Venlafaxin Orion, Venlafaxine Bluefish, Venlafaxin Teva, Venlafaxin Liconsa, and Venlafaxin Sandoz. It is typically formulated as extended-release (depot) capsules or tablets, which allow for once-daily dosing and help reduce peak-related side effects such as nausea.
Approved Indications
Venlafaxine is approved by regulatory authorities including the EMA and FDA for the treatment of the following conditions in adults:
- Major depressive disorder (MDD): Treatment of acute episodes and prevention of recurrence of depression
- Generalized anxiety disorder (GAD): Characterized by persistent excessive worry and anxiety about everyday matters
- Social anxiety disorder (social phobia): Intense fear and avoidance of social situations due to concerns about embarrassment or negative judgment
- Panic disorder: Characterized by recurrent, unexpected panic attacks with or without agoraphobia
Depression is a clinical illness characterized by persistent low mood, loss of interest or pleasure in activities, sleep disturbances, fatigue, difficulty concentrating, changes in appetite, and feelings of worthlessness or excessive guilt. Generalized anxiety disorder involves chronic, excessive worry about multiple aspects of daily life that is difficult to control and causes significant distress. Social anxiety disorder is characterized by marked fear of social situations where the person may be exposed to possible scrutiny by others. Panic disorder involves sudden episodes of intense fear accompanied by physical symptoms such as rapid heartbeat, sweating, trembling, shortness of breath, and a sense of impending doom.
It is essential to treat depression and anxiety disorders properly to help you feel better. If left untreated, these conditions may not resolve on their own and can become more severe and harder to treat over time. Your doctor has assessed that venlafaxine is appropriate for your specific condition. Always follow your doctor's instructions regarding dosage and duration of treatment.
What Should You Know Before Taking Venlafaxine?
Before taking venlafaxine, you must inform your doctor about all medical conditions, other medications, and whether you are pregnant or breastfeeding. Venlafaxine must never be combined with MAO inhibitors due to the risk of potentially fatal serotonin syndrome. Special caution is needed for patients with high blood pressure, heart problems, glaucoma, epilepsy, bleeding disorders, or a history of bipolar disorder or suicidal thoughts.
Contraindications
You must not take venlafaxine in the following situations:
- Allergy to venlafaxine or any of the other ingredients in the capsules or tablets
- If you are taking or have recently taken irreversible MAO inhibitors (monoamine oxidase inhibitors) used to treat depression or Parkinson's disease. You must wait at least 14 days after stopping an irreversible MAO inhibitor before starting venlafaxine, and at least 7 days after stopping venlafaxine before starting an MAO inhibitor
Combining venlafaxine with MAO inhibitors can cause serotonin syndrome, a potentially life-threatening condition. Symptoms include confusion, agitation, rapid heartbeat, high blood pressure, dilated pupils, muscle twitching, high fever, and diarrhea. If you experience these symptoms, seek emergency medical attention immediately. The mandatory washout period must be strictly observed.
Warnings and Precautions
Talk to your doctor or pharmacist before taking venlafaxine if you have or have previously had any of the following conditions:
- Eye problems: Certain types of glaucoma (increased pressure in the eye) require caution, as venlafaxine may cause mydriasis (pupil dilation)
- High blood pressure: Venlafaxine can cause dose-dependent increases in blood pressure. Regular monitoring is recommended, particularly at higher doses
- Heart problems or abnormal heart rhythm: Including conditions that may predispose to cardiac arrhythmias
- Epilepsy or seizures: Venlafaxine may lower the seizure threshold; contact your doctor immediately if you experience a seizure
- Low sodium levels (hyponatremia): This can occur during treatment, particularly in elderly patients or those taking diuretics
- Bleeding disorders: Or use of medications that increase bleeding risk (e.g. warfarin, NSAIDs). Venlafaxine may affect platelet function
- Mania or bipolar disorder: If you or a family member has a history of manic episodes or bipolar disorder
- Aggressive behavior: History of aggression should be discussed with your doctor
Restlessness (Akathisia)
Venlafaxine may cause a feeling of restlessness or an inability to sit or stand still, particularly during the first few weeks of treatment. This condition, known as akathisia, can be distressing and may be mistaken for worsening anxiety. If you develop such symptoms, inform your doctor. Increasing the dose may not be helpful and could worsen the condition.
Dry Mouth and Dental Health
Dry mouth has been reported in approximately 10% of patients treated with venlafaxine. Persistent dry mouth can increase the risk of dental cavities (caries). If you experience dry mouth, you should pay extra attention to dental hygiene, drink water regularly, and consider sugar-free gum or saliva substitutes. Inform your dentist that you are taking venlafaxine.
Suicidal Thoughts and Worsening of Depression or Anxiety
If you are depressed or suffer from anxiety, you may sometimes have thoughts of self-harm or suicide. These thoughts may increase when first starting antidepressant treatment, as it takes time for these medications to take effect, usually approximately 2 weeks and sometimes longer. These thoughts may also occur when the dose is reduced or when treatment is stopped.
These thoughts are more likely if you:
- Have previously had thoughts of self-harm or suicide
- Are a young adult under 25 years of age. Clinical studies have shown that young adults with psychiatric conditions treated with antidepressants have an increased risk of suicidal behavior
If you have thoughts of self-harm or suicide at any time, contact your doctor immediately or go to the nearest emergency department. It may be helpful to tell a relative or close friend that you are depressed or anxious, and to ask them to read this information. Ask them to tell you if they think your condition is getting worse or if they are worried about changes in your behavior.
Blood Pressure Monitoring
Venlafaxine can cause sustained increases in blood pressure that are dose-dependent. Approximately 3% of patients treated with venlafaxine experience clinically significant blood pressure elevation. This effect is more common at higher doses (above 150 mg/day). Your doctor should measure your blood pressure before starting treatment and monitor it regularly throughout therapy, especially when doses are increased. If you develop sustained high blood pressure, your doctor may consider reducing the dose or discontinuing the medication.
Sexual Dysfunction
Medications such as venlafaxine (SNRIs and SSRIs) can cause symptoms of sexual dysfunction, including decreased libido, delayed ejaculation, erectile difficulties, and anorgasmia. In some cases, these symptoms have persisted after discontinuation of treatment. If you experience sexual side effects, discuss them openly with your doctor, as alternatives or adjunctive treatments may be available.
Diabetes
Venlafaxine may affect blood sugar levels. If you have diabetes, the dose of your diabetes medication may need to be adjusted during treatment with venlafaxine. Discuss blood glucose monitoring with your doctor.
Pregnancy and Breastfeeding
If you are pregnant, breastfeeding, think you may be pregnant, or are planning to have a baby, consult your doctor before taking venlafaxine. Do not use this medication until you have discussed the potential benefits and risks with your doctor.
When similar medications (SSRIs/SNRIs) are used during pregnancy, the risk may increase for a serious condition in the newborn called persistent pulmonary hypertension of the newborn (PPHN), which causes the baby to breathe faster and appear bluish. Symptoms usually appear within 24 hours of birth. Other symptoms in newborns may include breathing difficulties, feeding problems, irritability, tremor, and seizures. If your newborn has any of these symptoms, contact your doctor or midwife immediately.
Taking venlafaxine at the end of pregnancy may increase the risk of heavy vaginal bleeding shortly after delivery (postpartum hemorrhage), especially if you have a history of bleeding disorders. Your doctor or midwife should be informed that you are taking venlafaxine so they can advise you accordingly.
Venlafaxine passes into breast milk and there is a risk that the infant may be affected. You should discuss with your doctor whether to stop breastfeeding or to discontinue venlafaxine treatment.
Children and Adolescents
Venlafaxine should generally not be used for treating children and adolescents under 18 years of age. The risk of side effects such as suicidal behavior, self-harm thoughts, and hostility (primarily aggression, defiance, and anger) is greater in patients under 18 when they take medications of this type. Despite this, a doctor may decide to prescribe venlafaxine to a patient under 18 if they consider it to be in the patient's best interest. The long-term effects of this medication on growth, maturation, and cognitive and behavioral development have not yet been established in this age group.
Driving and Operating Machinery
Do not drive or operate machinery until you know how venlafaxine affects you. This medication can cause drowsiness, dizziness, and visual disturbances that may impair your ability to drive safely or operate machinery. You are personally responsible for assessing whether you are fit to perform these activities. Discuss with your doctor if you are unsure.
Alcohol
Do not drink alcohol while being treated with venlafaxine. Combining alcohol with venlafaxine can lead to extreme drowsiness and loss of consciousness. Alcohol can also worsen symptoms of depression and anxiety, counteracting the therapeutic effects of the medication.
How Does Venlafaxine Interact with Other Drugs?
Venlafaxine has significant interactions with several medications. It must never be combined with MAO inhibitors due to the risk of potentially fatal serotonin syndrome. Many other medications, including lithium, triptans, tramadol, St. John's Wort, and other serotonergic drugs, require careful monitoring when taken with venlafaxine. Additionally, some medications may affect venlafaxine's metabolism or heart rhythm. Always inform your doctor of all medications you are taking.
Tell your doctor or pharmacist if you are taking, have recently taken, or might take any other medications, including those purchased without a prescription and herbal or natural remedies. Do not start or stop any medications without consulting your doctor or pharmacist first. Some medications can affect how venlafaxine works, and venlafaxine can affect how other medications work.
Serotonin Syndrome
A potentially life-threatening condition called serotonin syndrome, or reactions resembling neuroleptic malignant syndrome (NMS), can occur during treatment with venlafaxine, particularly when taken together with certain other medications. Symptoms include restlessness, hallucinations, loss of coordination, rapid heartbeat, elevated body temperature, rapid changes in blood pressure, overactive reflexes, diarrhea, nausea, vomiting, and in severe cases, coma. If you experience any combination of these symptoms, seek emergency medical attention immediately.
Major Interactions (Do Not Combine)
| Medication | Type | Risk |
|---|---|---|
| Irreversible MAO inhibitors (e.g. phenelzine, tranylcypromine) | Antidepressants | Serotonin syndrome – potentially life-threatening. 14-day washout before starting venlafaxine; 7-day washout after stopping venlafaxine. |
Moderate Interactions (Use with Caution)
| Medication | Type | Effect |
|---|---|---|
| Triptans (e.g. sumatriptan) | Migraine medication | Increased risk of serotonin syndrome. |
| Other SSRIs/SNRIs (e.g. sertraline, duloxetine) | Antidepressants | Increased serotonergic activity; risk of serotonin syndrome. |
| Tricyclic antidepressants (e.g. amitriptyline) | Antidepressants | Increased serotonergic effects and potential for serotonin syndrome. |
| Lithium | Mood stabilizer | Increased risk of serotonin syndrome. Monitor lithium levels closely. |
| Tramadol, Fentanyl, Buprenorphine, Pethidine | Opioid analgesics | Risk of serotonin syndrome and seizures. |
| St. John's Wort (Hypericum perforatum) | Herbal supplement | Increased serotonergic activity; risk of serotonin syndrome. |
| Tryptophan | Amino acid supplement | Increased serotonergic effects. |
| Amphetamines | ADHD / narcolepsy medication | Risk of serotonin syndrome. |
| Dextromethorphan | Cough suppressant | Increased serotonergic activity; risk of serotonin syndrome. |
| Methylene blue (intravenous) | Diagnostic / therapeutic agent | MAO inhibitor activity; risk of serotonin syndrome. |
| Linezolid | Antibiotic | Weak MAO inhibitor; risk of serotonin syndrome. |
| Warfarin | Blood thinner | Increased bleeding risk. INR monitoring required. |
| Ketoconazole | Antifungal | CYP3A4 inhibitor; may increase venlafaxine levels. |
| Haloperidol, Risperidone | Antipsychotics | Venlafaxine may increase levels of these drugs. |
| Metoprolol | Beta-blocker | Venlafaxine may increase metoprolol levels via CYP2D6 inhibition. |
Medications Affecting Heart Rhythm
You must inform your doctor if you are taking medications that may affect your heart rhythm, including:
- Antiarrhythmics: Quinidine, amiodarone, sotalol, dofetilide
- Antipsychotics: Thioridazine and others
- Antibiotics: Erythromycin, moxifloxacin
- Antihistamines: Certain older-generation antihistamines
Food and Alcohol Interactions
Venlafaxine should be taken with food, as this can reduce the incidence of nausea. Extended-release capsules should be swallowed whole with liquid and must not be opened, crushed, chewed, or dissolved. The following should be noted:
- Alcohol: Must be avoided during treatment. Combining alcohol with venlafaxine can lead to extreme drowsiness and loss of consciousness, and can worsen depression and anxiety symptoms
What Is the Correct Dosage of Venlafaxine?
The usual recommended starting dose of venlafaxine for depression, generalized anxiety, and social anxiety is 75 mg once daily. The dose can be gradually increased by the doctor up to a maximum of 375 mg per day for depression and 225 mg per day for anxiety disorders. For panic disorder, treatment starts at 37.5 mg daily. Extended-release capsules should be taken once daily with food, at approximately the same time each day.
Adults
| Condition | Starting Dose | Usual Dose | Maximum Dose |
|---|---|---|---|
| Depression | 75 mg/day | 75–225 mg/day | 375 mg/day |
| Generalized Anxiety Disorder | 75 mg/day | 75–225 mg/day | 225 mg/day |
| Social Anxiety Disorder | 75 mg/day | 75 mg/day | 225 mg/day |
| Panic Disorder | 37.5 mg/day | 75–225 mg/day | 225 mg/day |
Doses may be increased in increments as directed by your doctor. For depression, dose adjustments can be made at intervals of at least 2 weeks, and for panic disorder, a lower starting dose of 37.5 mg/day for 4–7 days is recommended before increasing to 75 mg/day. Your doctor will determine the appropriate dose based on your individual condition and response to treatment. Treatment for depression should usually continue for at least 6 months after clinical improvement.
Children and Adolescents
Venlafaxine is not recommended for use in children and adolescents under 18 years of age. Clinical studies in this age group did not demonstrate sufficient efficacy, and there was an increased risk of suicidal thoughts and hostile behavior. The long-term effects on growth, maturation, and cognitive development have not been established.
Elderly and Patients with Liver or Kidney Problems
Elderly patients may be more susceptible to certain side effects, particularly hyponatremia (low sodium levels). No dose adjustment is specifically recommended for elderly patients, but caution should be exercised and the lowest effective dose used.
If you have liver problems, your doctor should reduce your dose by approximately 50%. If you have moderate to severe kidney problems, your dose may also need to be reduced. Discuss your kidney and liver function with your doctor before starting treatment.
How to Take Venlafaxine
Always take venlafaxine exactly as your doctor has instructed. Take the extended-release capsules or tablets at approximately the same time each day, either in the morning or in the evening, with food. Swallow the capsules whole with liquid – do not open, crush, chew, or dissolve them. The extended-release formulation is designed to release the active substance gradually over time, ensuring steady blood levels throughout the day.
Missed Dose
If you forget to take a dose, take it as soon as you remember. However, if it is nearly time for your next dose, skip the missed dose and take the next dose at the usual time. Do not take a double dose to make up for the missed one. Do not take more than your prescribed daily dose of venlafaxine.
Overdose
If you take too much venlafaxine, or if a child accidentally ingests the medication, contact your doctor, hospital emergency department, or poison control center immediately. Overdose can be life-threatening, particularly when combined with alcohol or other medications.
Symptoms of overdose may include:
- Rapid heartbeat or changes in heart rhythm
- Changes in level of consciousness (from drowsiness to coma)
- Blurred vision
- Seizures
- Vomiting
Stopping Venlafaxine
Do not stop taking venlafaxine or reduce your dose without first consulting your doctor, even if you feel better. Venlafaxine is known for causing particularly pronounced withdrawal symptoms compared to many other antidepressants, especially if treatment is stopped abruptly or the dose is reduced too quickly.
Withdrawal symptoms may include:
- Dizziness, vertigo, and light-headedness
- Electric shock-like sensations (“brain zaps”)
- Headache
- Insomnia and nightmares
- Nausea, diarrhea, and dry mouth
- Anxiety, agitation, and confusion
- Sweating and flu-like symptoms
- Tingling sensations (paresthesia)
- Visual disturbances
- In rare cases, seizures or elevated blood pressure
Your doctor will advise you on how to gradually reduce and discontinue venlafaxine treatment. This may take several weeks or even months. For some patients, the tapering process may need to occur very gradually over an extended period. If you experience troublesome withdrawal symptoms at any stage, consult your doctor.
What Are the Side Effects of Venlafaxine?
Like all medicines, venlafaxine can cause side effects, although not everyone experiences them. The most common side effects include nausea, dry mouth, headache, dizziness, drowsiness, insomnia, constipation, and sweating. Venlafaxine can also cause dose-dependent increases in blood pressure. Serious side effects such as serotonin syndrome, severe allergic reactions, and suicidal thoughts require immediate medical attention.
Swelling of the face, mouth, tongue, throat, hands, or feet; difficulty breathing or swallowing; severe skin rash with blisters; symptoms of serotonin syndrome (confusion, rapid heartbeat, fever, muscle rigidity); chest pain with shortness of breath (stress cardiomyopathy); signs of infection such as high fever with chills; or thoughts of self-harm or suicide.
Very Common
Affects more than 1 in 10 people
- Dizziness
- Headache
- Drowsiness (somnolence)
- Insomnia
- Nausea
- Dry mouth
- Constipation
- Excessive sweating (including night sweats)
Common
Affects 1 in 10 to 1 in 100 people
- Decreased appetite
- Confusion, feeling detached, decreased libido
- Agitation, nervousness, abnormal dreams
- Tremor, restlessness (akathisia), tingling/numbness
- Changes in taste, increased muscle tension
- Visual disturbances, dilated pupils, inability to focus
- Tinnitus (ringing in ears)
- Rapid heartbeat, palpitations
- Elevated blood pressure, flushing
- Shortness of breath, yawning
- Vomiting, diarrhea
- Mild skin rash, itching
- Frequent urination, difficulty urinating
- Irregular menstruation, abnormal ejaculation/orgasm
- Erectile dysfunction
- Weakness (asthenia), fatigue, chills
- Weight gain, weight loss
- Elevated cholesterol levels
Uncommon
Affects 1 in 100 to 1 in 1,000 people
- Mania or hypomania (overactivity, racing thoughts)
- Hallucinations, feeling detached from reality
- Abnormal orgasm, teeth grinding (bruxism)
- Fainting (syncope), involuntary muscle movements
- Impaired coordination and balance
- Dizziness on standing (postural hypotension)
- Gastrointestinal bleeding (black stools, bloody vomit)
- Sensitivity to sunlight, easy bruising
- Hair loss (alopecia)
- Urinary incontinence
- Muscle stiffness, spasms, involuntary movements
- Changes in liver enzyme levels
Rare and Very Rare
Affects fewer than 1 in 1,000 people
- Seizures (convulsions)
- Serotonin syndrome or neuroleptic malignant syndrome
- Delirium (disorientation and confusion with hallucinations)
- SIADH (syndrome of inappropriate antidiuretic hormone secretion)
- Low sodium levels in the blood (hyponatremia)
- Severe eye pain or vision changes (angle-closure glaucoma)
- Abnormal heart rhythm (arrhythmia) which may cause fainting
- Severe abdominal or back pain (pancreatitis)
- Hepatitis (inflammation of the liver)
- Prolonged bleeding time (decreased platelet function)
- Rhabdomyolysis (muscle breakdown)
- Unexpected bleeding (gums, urine, or skin)
- Abnormal breast milk production (galactorrhea)
- Stress cardiomyopathy (chest pain, shortness of breath)
Withdrawal Symptoms
Withdrawal effects when stopping venlafaxine are common, particularly if treatment is stopped abruptly or the dose is reduced too quickly. Venlafaxine is known for having more pronounced withdrawal symptoms than many other antidepressants. Symptoms may include suicidal thoughts, aggression, fatigue, dizziness, feeling of intoxication, headache, insomnia, nightmares, dry mouth, loss of appetite, nausea, diarrhea, nervousness, anxiety, confusion, tinnitus, tingling sensations, and in rare cases, electric shock-like sensations, weakness, sweating, seizures, or flu-like symptoms. See the section on “Stopping Venlafaxine” under Dosage for detailed guidance.
Venlafaxine can sometimes cause side effects you may not be aware of, including elevated blood pressure, abnormal heart rhythm, and changes in blood levels of liver enzymes, sodium, or cholesterol. Your doctor may want to perform blood tests and blood pressure checks periodically, particularly if you have been taking venlafaxine for an extended period.
How Should You Store Venlafaxine?
Store venlafaxine at room temperature in the original packaging, out of the reach and sight of children. Do not use the medication after the expiry date printed on the packaging. No special storage conditions are required. Do not dispose of medications via wastewater or household waste.
Keep venlafaxine out of the reach and sight of children. Do not use the medication after the expiry date stated on the carton and blister pack after “EXP.” The expiry date refers to the last day of that month. No special storage conditions are required for venlafaxine extended-release capsules.
Do not throw away medications in wastewater or household waste. Ask your pharmacist how to dispose of medications that are no longer needed. These measures help protect the environment.
What Does Venlafaxine Contain?
Each venlafaxine extended-release capsule contains venlafaxine hydrochloride as the active ingredient, equivalent to 37.5 mg, 75 mg, or 150 mg of venlafaxine. The capsules contain multiple film-coated mini-tablets that release the active substance gradually. Inactive ingredients include microcrystalline cellulose, povidone, talc, colloidal silicon dioxide, magnesium stearate, ethylcellulose, and copovidone.
Active Ingredient
The active substance is venlafaxine hydrochloride. Each extended-release capsule contains venlafaxine hydrochloride equivalent to:
- 37.5 mg venlafaxine (42.45 mg venlafaxine hydrochloride) – contains 3 mini-tablets of 12.5 mg each
- 75 mg venlafaxine (84.9 mg venlafaxine hydrochloride) – contains 6 mini-tablets of 12.5 mg each
- 150 mg venlafaxine (169.8 mg venlafaxine hydrochloride) – contains 12 mini-tablets of 12.5 mg each
Inactive Ingredients (Excipients)
Capsule contents: Microcrystalline cellulose, povidone (K90 D), talc, colloidal anhydrous silicon dioxide, magnesium stearate, ethylcellulose, and copovidone.
Capsule shell: Varies by strength. May contain iron oxides (E172), titanium dioxide (E171), gelatin, and purified water. The 150 mg capsule also contains brilliant blue FCF (E133), allura red AC (E129), and sunset yellow FCF (E110).
The 37.5 mg capsule is light grey/peach-colored. The 75 mg capsule is peach/peach-colored. The 150 mg capsule is dark orange. All capsules contain white to off-white, round, biconvex, film-coated mini-tablets. The medication contains less than 1 mmol (23 mg) sodium per capsule, making it essentially sodium-free.
The 150 mg capsule contains the azo dyes sunset yellow FCF (E110) and allura red AC (E129), which may cause allergic reactions in some individuals. If you have known sensitivities to azo dyes, discuss this with your doctor or pharmacist.
Frequently Asked Questions About Venlafaxine
Venlafaxine typically begins to show some improvement within 1–2 weeks, but it usually takes 4–6 weeks of consistent daily use to experience the full therapeutic benefit. For anxiety disorders, the full effect may take up to 8 weeks. It is essential to continue taking venlafaxine as prescribed even if you do not notice immediate improvement. Your doctor will monitor your progress and may adjust the dosage if needed.
No, alcohol should be avoided while taking venlafaxine. Combining alcohol with venlafaxine can cause extreme drowsiness and even loss of consciousness. Alcohol can also worsen symptoms of depression and anxiety, counteracting the therapeutic benefits of the medication. If you have questions about alcohol consumption during treatment, speak with your doctor.
No, never stop venlafaxine abruptly. Venlafaxine is well-known for having particularly pronounced withdrawal symptoms compared to many other antidepressants. Sudden discontinuation can cause dizziness, electric shock-like sensations (“brain zaps”), nausea, headache, insomnia, nightmares, anxiety, confusion, sweating, and flu-like symptoms. Your doctor will recommend a very gradual dose reduction over a period of several weeks or even months. Never change your dose without consulting your doctor first.
Yes, venlafaxine can cause dose-dependent increases in blood pressure. This effect is more common at higher doses (above 150 mg/day) and affects approximately 3% of patients. Your doctor should measure your blood pressure before starting treatment and monitor it regularly, especially when doses are increased. If you develop sustained high blood pressure, your doctor may consider reducing the dose or switching to a different medication.
Venlafaxine is an SNRI (serotonin-norepinephrine reuptake inhibitor), while SSRIs such as sertraline, fluoxetine, and citalopram only inhibit serotonin reuptake. Venlafaxine's dual mechanism of action means it affects both serotonin and norepinephrine levels in the brain. At lower doses it primarily acts like an SSRI, while at higher doses the norepinephrine effect becomes more prominent. This dual action may benefit patients who do not respond to SSRIs alone. However, venlafaxine also tends to have more pronounced withdrawal symptoms and can cause blood pressure elevation, which are less common with SSRIs.
The safety of venlafaxine during pregnancy has not been fully established. It should only be used when the potential benefit to the mother outweighs the possible risks to the baby. Use during the third trimester may increase the risk of persistent pulmonary hypertension of the newborn (PPHN), neonatal withdrawal symptoms, and heavy postpartum bleeding. Women who are pregnant, planning to become pregnant, or breastfeeding should discuss the risks and benefits thoroughly with their healthcare provider before making any treatment decisions.
References and Sources
This article is based on the following peer-reviewed sources and international guidelines. All medical claims are supported by evidence level 1A (systematic reviews and randomized controlled trials).
- European Medicines Agency (EMA). Venlafaxine – Summary of Product Characteristics (SmPC). EMA; 2024. Full prescribing information for the European Union.
- U.S. Food and Drug Administration (FDA). Effexor XR (venlafaxine hydrochloride) – Prescribing Information. FDA; 2024. Complete United States prescribing information.
- National Institute for Health and Care Excellence (NICE). Depression in adults: treatment and management. NICE guideline [NG222]. NICE; 2022. Updated 2024.
- Cipriani A, Furukawa TA, Salanti G, et al. Comparative efficacy and acceptability of 21 antidepressant drugs for the acute treatment of adults with major depressive disorder: a systematic review and network meta-analysis. Lancet. 2018;391(10128):1357-1366.
- British National Formulary (BNF). Venlafaxine. NICE BNF; 2025. Drug monograph with dosing, interactions, and side effects.
- Bauer M, Pfennig A, Severus E, et al. World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Unipolar Depressive Disorders. World J Biol Psychiatry. 2013;14(5):334-385.
- Baldwin DS, Anderson IM, Nutt DJ, et al. Evidence-based pharmacological treatment of anxiety disorders, post-traumatic stress disorder and obsessive-compulsive disorder: a revision of the 2005 guidelines from the British Association for Psychopharmacology. J Psychopharmacol. 2014;28(5):403-439.
- Fava GA, Gatti A, Belaise C, et al. Withdrawal symptoms after selective serotonin reuptake inhibitor discontinuation: a systematic review. Psychother Psychosom. 2015;84(2):72-81.
About the Medical Editorial Team
This article was written and reviewed by the iMedic Medical Editorial Team, consisting of licensed specialist physicians with expertise in clinical pharmacology, psychiatry, and evidence-based medicine.
All content is reviewed by board-certified physicians following international guidelines (WHO, EMA, FDA, BNF, NICE) and the GRADE evidence framework.
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Last medical review: | Published: | Evidence level: 1A (Systematic reviews and RCTs) | Next scheduled review: