How long do venlafaxine withdrawal symptoms last?

Venlafaxine withdrawal symptoms typically last up to 3 to 4 weeks, but may persist even longer. You should avoid abruptly stopping venlafaxine treatment unless otherwise directed by your healthcare provider. Gradually reducing the dose over 4 weeks can help to prevent severe withdrawal symptoms in most people.

Do not stop treatment on your own. Your doctor can set up a tapering schedule to help you safely discontinue venlafaxine.

What is antidepressant discontinuation syndrome?

Withdrawal side effects from antidepressants, also called antidepressant discontinuation syndrome, is a common occurrence with all classes of antidepressants.

Abruptly stopping antidepressant treatment, or tapering your dose down too quickly, can result in side effects if you’ve been on treatment for at least a few weeks. These withdrawal side effects, which are usually mild but can be severe in some people, typically start 1 to 3 days after stopping treatment.

Which side effects occur if venlafaxine is stopped too quickly?

The most common side effects that may occur with abruptly stopping venlafaxine (Effexor, Effexor XR) may include:

• dizziness
• headache
• feeling tired
• anxiety
• trouble sleeping
• nausea
• loss of appetite
• irritability

Other reported symptoms are: chills, confusion, diarrhea, dry mouth, excessive sweating, feeling of unease, electric shock-like sensations ("brain zaps"), muscle aches, burning or tingling sensation in hand, arm, foot or other extremity (paresthesias), runny nose, tremor, vertigo, vomiting and vivid dreams or nightmares.

How slowly should venlafaxine be stopped?

Follow your doctor's directions on how to best discontinue venlafaxine (Effexor, Effexor XR).

In general, it is recommended the daily dose of venlafaxine be reduced by 37.5 to 75 mg each week over four weeks to reduce symptoms. This applies to both immediate-release and extended-release formulations.

• For example, if you are taking 300 mg per day of venlafaxine, your doctor may decide to lower your dose by 75 mg each week for 4 weeks until you are done with the medicine at the end of week 4.
• As another example, if you take a 150 mg dose, your doctor may decide to taper your dose by 37.5 mg each week for 4 weeks until you are done with the medicine at the end of week 4.

For some doses, your doctor may need to prescribe different strengths to help you correctly taper your dose over 4 weeks.

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Why does venlafaxine cause withdrawal symptoms?

Quickly stopping venlafaxine treatment can lead to withdrawal symptoms due to its short half-lives, ranging from 5 to 13 hours. Studies have shown that SNRIs such as venlafaxine and desvenlafaxine can have relatively more side effects when treatment is stopped abruptly.

A half-life is the time it takes a dose of the drug to be reduced by one-half. It takes on average 4 to 5 half-lives for a drug to be fully eliminated.

Quick elimination from the body of drugs with short-half lives can worsen discontinuation withdrawal symptoms, especially drugs that work in the central nervous system like antidepressants or benzodiazepines. Taking higher doses and being on treatment for a longer period of time may also worsen these side effects.

The half-life can vary based on your age, weight, genetic make-up, kidney or liver function, drug interactions, and even your medical conditions. Your doctor may decide to discontinue your dose even more slowly due to these factors.

Do not stop treatment on your own. Conact your doctor, who can set up a safe and more comfortable tapering schedule for you.

In contrast, Prozac (fluoxetine) is an SSRI antidepressant with a very long half-life (ranging from 4 to 16 days). Plasma levels of the drug decrease gradually when treatment is stopped which may minimize the risk of discontinuation symptoms with this drug, but a long half-life also means that side effects due to the drug itself may be ongoing as the drug slowly eliminates from the body.

What should I do if I get withdrawal symptoms with venlafaxine?

• Contact your doctor right away.
• If you abruptly stopped treatment, your healthcare provider may decide to restart your venlafaxine and slowly lower your dose over several weeks or longer to help reduce the incidence of side effects.
• If you are already undergoing a gradual treatment discontinuation, your dose may need to be slightly increased and then stopped even more slowly to help reduce your side effects.

This is not all the information you need to know about venlafaxine (Effexor, Effexor XR) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.