Venlafaxine belongs to a class of antidepressants known as serotonin-norepinephrine reuptake inhibitors (SNRIs). It helps increase the level of certain neurotransmitters that regulate mood.
While doctors typically use it to treat depression, venlafaxine also has approval for treating people with anxiety. However, using it involves carefully following a doctor’s advice and proceeding with caution if you notice any negative side effects.
Venlafaxine for anxiety
Venlafaxine (Effexor) works by increasing the levels of serotonin and norepinephrine in the brain, which produces a calming effect and improves mood. It is effective against various types of anxiety and panic disorders.
Venlafaxine is typically taken orally, either as a tablet or as an extended-release (XR) capsule. The dose and frequency of venlafaxine varies for each person. A 2017 meta-analysis found that venlafaxine XR is very effective and well-tolerated in treating generalized anxiety disorder (GAD) in adults.
According to the National Alliance on Mental Illness (NAMI), suddenly stopping venlafaxine can lead to withdrawal symptoms, including:
- nausea and vomiting
- dizziness
- headaches
- nightmares
- tingling skin
You might also experience your original symptoms returning. So, it’s important to follow the doctor’s instructions and continue the medication even when you feel better. You should always seek the advice of a healthcare professional before deciding to stop taking venlafaxine.
Experts recommend taking venlafaxine should be under the guidance of a qualified medical professional to ensure safety and promote effectiveness.
How long does it take to work?
According to NAMI, some symptoms may show improvement as soon as 1–2 weeks after starting venlafaxine. But it might take up to 2 months to notice the full benefits and improvements in your mood.
Different medications will affect everyone differently, and it’s common to try various types of anxiety medications before finding one that works for you. But it’s important to give venlafaxine at least 8 weeks to get to work before you decide to switch.
Low dose vs. high dose
A doctor may start with a low or high dose of venlafaxine, depending on your medical history and symptoms.
Low dose venlafaxine is typically suitable for people with mild or moderate anxiety. Doctors usually start with low dose venlafaxine as starting at a higher dose can worsen symptoms or lead to more side effects. If you don’t respond to the low dose, they may consider a higher dose.
A 2018 review suggests that SNRIs like venlafaxine don’t become much more effective as you increase the dose, but tolerability becomes lower. This means the negative side effects outweigh the benefits.
So, high dose venlafaxine may increase the risk of serious side effects, such as chest pain and difficulty breathing. Doctors typically weigh the benefits of venlafaxine with the potential side effects to decide the appropriate dose.
A thorough assessment and investigation of your symptoms and history may be necessary. Note that high doses of venlafaxine will still fall within a range approved by the Food and Drug Administration (FDA).
Possible side effects
There are various side effects of venlafaxine, which vary for each person. Possible side effects include:
- nausea and vomiting
- stomach pain
- constipation or diarrhea
- heartburn
- drowsiness
- dizziness and headache
- nightmares
- loss of appetite
- weight loss
- changes in sex drive
In some cases, there could be severe side effects, such as:
- itching
- difficulty breathing or swallowing
- chest pain
- seizures
- unusual bruising or bleeding, especially if combined with medications like ibuprofen
- fast or irregular heartbeat
- problems with coordination
- visual or auditory hallucinations
- loss of consciousness
SNRIs like venlafaxine can also increase the risk of serotonin syndrome, a condition caused by too much serotonin in your system. This leads to serious symptoms like fast heart rate, anxiety, and agitation, and it can lead to seizures or even death.
Serotonin syndrome is more common if you take venlafaxine with other medications that increase serotonin levels, such as triptan medications for migraine.
Contact a healthcare professional immediately if you notice any of these side effects.
