Venlafaxine

What is venlafaxine?

Venlafaxine is a prescription antidepressant that belongs to a class of medications called serotonin-noradrenaline reuptake inhibitors (SNRIs)[1]. 

What is venlafaxine used to treat?

Venlafaxine is prescribed for adults to treat[1]: 

• Major depressive disorder (MDD) 

• Generalized anxiety disorder (GAD) 

• Social anxiety disorder (SAD) 

• Panic disorder 

How does venlafaxine work?

It works by increasing the levels of serotonin and noradrenaline, natural substances in the brain that improve mood. By increasing their levels, it helps improve mood and reduce anxiety[1]. 

Who can take venlafaxine?

Most adults can take venlafaxine although it is not suitable for everyone[1]. 

You should check with your doctor or pharmacist before taking if: 

• You have ever had an allergic reaction to venlafaxine 

• You are pregnant or breastfeeding 

• You have heart problems or glaucoma 

Please tell your doctor or pharmacist about any conditions you may have before you start treatment and always read the guidance in the Patient Information Leaflet[2]. 

How do you take venlafaxine?

Venlafaxine comes in both standard (twice a day) and slow-release (once a day) tablet and capsule form. It is best to take it whole, not crushed or chewed, at the same time each day and you should take it with food[1]. 

What is the typical dosage for venlafaxine?

Typical starting doses are[1]: 

• Depression: 75 mg daily but may increase over time 

• Panic disorders: Start at 37.5 mg daily but may increase over time 

The maximum dose can go up to 375 mg per day, depending on the condition being treated. 

Can you stop taking venlafaxine?

You should not stop taking venlafaxine suddenly as you may get withdrawal symptoms. These effects can include dizziness, irritability, nausea, and headaches. Speak to your doctor or pharmacist if you want to stop taking venlafaxine[1]. 

What do you do if you take too much venlafaxine?

Taking too much venlafaxine can cause symptoms such as rapid heartbeat, seizures, drowsiness, and vomiting. Call 111 straight away for advice if you’ve taken more than your prescribed dose. Call 999 or go to A&E immediately if you suspect an overdose and show symptoms[1]. 

What do you do if you forget a dose of venlafaxine?

If you miss a dose, take it as soon as you remember. If it's almost time for your next dose, skip the missed dose and continue with your regular schedule. Never take 2 doses at the same time[1]. 

What are the side effects of venlafaxine?

The most common side effects of venlafaxine are[1]: 

• Nausea 

• Dry mouth 

• Sweating 

• Drowsiness  

• Unable to sleep  

• Dizziness 

• Headache 

• constipation 

The rare but more serious side effects include[1]: 

• Suicidal thoughts 

• Serotonin syndrome (confusion, fever, tremors) 

• Eye pain or vision changes (risk of glaucoma) 

Call 111 or go to A&E if you are experiencing any of these serious side effects. 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Medicines you can and can’t take with venlafaxine

Venlafaxine is generally safe to take alongside other medications. However, there are some drugs that should be avoided or used with caution, as they may increase the risk of side effects or interactions. These include[1]: 

• MAO inhibitors (e.g., phenelzine, tranylcypromine) - These should not be taken with venlafaxine 

• Other antidepressants - should be used with caution due to the risk of serotonin syndrome 

• Stimulants, opioids, migraine medications like triptans – should be used with caution as these can also raise serotonin levels 

• Medicines that affect your heart rhythm such as certain antiarrhythmics or antibiotics – should be used with caution as venlafaxine may also affect the rhythm of your heart 

• NSAIDs (e.g., ibuprofen) - should be used with caution due to the increased risk of a stomach bleed 

• Herbal remedies such as St John's wort – should be avoided as they may increase the risk of side effects 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2].

Frequently asked questions about venlafaxine

How long does venlafaxine take to work? 

You may notice some improvement in 1 to 2 weeks, but full effects can take 4 to 6 weeks[1]. 

Can venlafaxine cause weight gain or loss? 

Both are possible. Some people lose weight due to appetite suppression, while others may gain weight over time[1]. 

Is venlafaxine addictive? 

It’s not addictive, but stopping suddenly can cause withdrawal symptoms such as headaches, nausea and feeling sick[1]. 

Can I drink alcohol while taking venlafaxine? 

You are able to drink alcohol, but it can make you sleepier. It is best to avoid drinking alcohol until you see how venlafaxine affects you[1]. 

Can venlafaxine affect sleep? 

Yes. It may cause insomnia or drowsiness, depending on the individual[1]. 

Can I drive or ride a bike while taking venlafaxine? 

Some people have difficulty concentrating when they take venlafaxine. It is best not to drive or cycle until you know how the medicine makes you feel[1]. 

Will venlafaxine affect my contraception? 

Venlafaxine does not affect your contraception. However, if you are sick or get diarrhoea, your contraceptive pills may not protect you. For more information read the leaflet that comes with your contraceptive pill[1].

For the official NHS guide to venlafaxine, visit their website.