Effexor (venlafaxine) is an antidepressant medication that belongs to the class of drugs known as serotonin-norepinephrine reuptake inhibitors (SNRIs). Withdrawal symptoms can occur after stopping Effexor, especially if it is done abruptly or too quickly. The onset of withdrawal symptoms can vary from person to person and depends on factors such as the individual's dosage, how long they have been taking the medication, and their body's response to the drug.
In general, Effexor withdrawal symptoms can start as soon as a few hours after the last dose, particularly for short-acting formulations. The half-life of immediate-release Effexor is around 5 hours, meaning it takes about 5 hours for half of the drug to be eliminated from the body.
For the extended-release formulation of Effexor (Effexor XR), which has a longer half-life, withdrawal symptoms may start within 24 to 48 hours after the last dose.
Common withdrawal symptoms from Effexor can include dizziness, nausea, headache, fatigue, irritability, anxiety, brain "zaps" or "shivers" (a sensation described as electric shock-like feelings in the head), and flu-like symptoms. These symptoms can vary in intensity and duration, with some people experiencing more prolonged withdrawal effects.
To minimize the risk of withdrawal symptoms, it is essential to work closely with a healthcare professional when discontinuing Effexor. They can provide a tapering schedule, gradually reducing the dosage over time to help ease the transition and reduce the likelihood of severe withdrawal effects. Stopping antidepressant medication suddenly or without proper medical guidance is not recommended.