If you've recently discontinued an antidepressant, you might experience flu-like symptoms as part of withdrawal (known as antidepressant discontinuation syndrome, or ADS). You may have symptoms after missing only a single dose or taking it late. Or, symptoms may come on several days after you stop your medication, making it harder to connect the dots.
Causes of Flu-Like Symptoms
Symptoms such as fatigue, nausea, chills, and muscle aches can indicate the flu. If it is flu season (October through March), you may indeed have influenza. However, flu-like symptoms occur with many infections besides the flu.
You can have similar symptoms due to colds (rhinoviruses), COVID-19 or other coronaviruses, human respiratory syncytial virus, adenoviruses, human parainfluenza virus, viral and bacterial pneumonia, Legionella, measles, acute HIV infection, herpes, hepatitis C, Lyme disease, and many others. Withdrawal symptoms from opioids can also mirror some of the symptoms of influenza.
Discontinuing an Antidepressant
Because any single antidepressant may be only 50% effective, you might think it isn't working and that stopping it won't have any effects. Or, you may not have refilled a prescription. You may simply have forgotten to take it.
However, even if you aren't getting the desired effects, antidepressants change your body chemistry. Suddenly removing the drugs will result in a sudden change of chemical reactions, resulting in withdrawal symptoms.
Symptoms of ADS
If you stop taking your antidepressant abruptly, without tapering your dosage, you can experience symptoms that range from mild to severe. You can experience discontinuation syndrome a few days or weeks after you stop taking your medication, even when tapering your dose, missing a dose, or taking a dose late. You might experience these symptoms for a few weeks.
Some will experience only minor symptoms and miss the connection with their antidepressant. For others, the symptoms are so debilitating that they feel they cannot stop their antidepressant for fear of how it will interfere with their lives.
Symptoms of antidepressant discontinuation syndrome include:
- Agitation
- Anxiety
- Blurred vision
- Dizziness
- Fatigue
- Hallucinations
- Insomnia
- Irritability
- Nausea
- Myalgia (muscle aches)
- Sweating
- Tingling or electric shock sensations (e.g., brain zaps)
- Vivid dreams
Medications Associated With ADS
Discontinuation syndrome is most common with those drugs that have a short half-life, which is how long it takes for half the drug to clear from the body.
- Selective serotonin reuptake inhibitors (SSRIs), including Zoloft (sertraline), Paxil (paroxetine), Celexa (citalopram), and Lexapro (escitalopram)
- Serotonin-norepinephrine reuptake inhibitors (SNRIs) such as Effexor (venlafaxine)
- Tricyclic antidepressants (TCAs) such as Elavil (amitriptyline)
- Monoamine oxidase inhibitors (MAOIs) such as Parnate (tranylcypromine)
There are exceptions to the rule. For example, Prozac (fluoxetine) is the one SSRI that generally does not cause problems because it has a half-life of two to four days, and its primary metabolite (breakdown product) has a half-life of four to 16 days. This long half-life gives it a built-in tapering effect.
Preventing ADS
If you are planning to discontinue your antidepressant, seek your doctor's approval and advice. When you stop your antidepressant, you run the risk of withdrawal symptoms as well as a possible return of the condition you are taking the antidepressant for. If your doctor has given you the green light to stop, discuss how you should proceed in gradually decreasing your dosage.
Tapering schedules can be quite variable. If your treatment has lasted less than six weeks, tapering is often done over one to two weeks. If you've been treated for six to eight months, tapering is done over six to eight weeks.
By gradually decreasing your dose over time, as directed by your doctor, you will allow your body time to adjust as the medication leaves your body. However, you should also take normal precautions to prevent the flu and other infectious diseases. Stay up to date on vaccinations and practice good handwashing habits.