Antidepressant Overdose

Antidepressants can be an effective means of treating depression, anxiety, and other mood disorders when used properly and taken in the prescribed doses. However, they can have side effects and be dangerous if taken incorrectly or used with alcohol or drugs. Some people may misuse or overdose on antidepressants—intentionally or not—to increase the drugs' effects or to commit suicide.

Overdoses are more commonly seen with older tricyclic antidepressants (TCAs), although newer selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) can also be misused. Learn the symptoms of overdose so you can get assistance or help someone who has taken too much of these medications.

Whether or not a person has accidentally or intentionally overdosed, the symptoms will typically be mild and non-specific in the first hour or two and progressively worsen over time.

The first signs are usually nausea, drowsiness, dry mouth, agitation, headache, vomiting, and diarrhea, all of which can easily be attributed to other causes. One of the earliest red flags may be a rapid and irregular heartbeat (tachycardia), a condition not commonly seen in young people. If an overdose is suspected, the combination of these symptoms warrants a call to 911 or an immediate visit to the emergency room.

As the more toxic effects emerge, symptoms may include:

• Confusion
• Delirium
• Hallucinations
• Tremors
• Involuntary eye movement
• Increasingly worsening heart pace (dysrhythmia)
• Respiratory distress
• Seizures
• Unconsciousness
• Coma

Seizures, cardiac dysrhythmia, respiratory distress, and coma are life-threatening complications.

Emergency medical interventions for an overdose typically include efforts to pump the person’s stomach and provide activated charcoal to absorb the remaining drugs. Both of these should be done within the first hour. Intravenous sodium bicarbonate and other medications may be prescribed to counteract the effects of the drug, and the person will also be kept hydrated with intravenous fluids. If there are breathing difficulties, the person may need mechanical ventilation. The heart will be monitored and treatment provided for any cardiac problems. If there are seizures, drugs will be given to control them.

Once stabilized, someone who has overdosed will be placed in an intensive care unit (ICU) for no less than 12 hours and released only after an electrocardiogram (ECG) remains normal for 24 hours. Before being released, a psychiatrist will evaluate the person and determine whether further interventions, such as a change in medications, increased psychiatric care, and/or substance abuse interventions are necessary.

Antidepressants are more likely to reduce suicide risk in the long run by improving mood, but in some cases they may increase suicidal thoughts or behavior, particularly in children, teenagers, and young adults under 25, especially in the first few weeks after starting or when the dose is changed. The FDA requires that all antidepressants carry black box warnings, which are the strictest warnings for prescriptions.

A study conducted in 2010 by the Centre for Suicide Research in Oxford, England aimed to identify which antidepressant drugs were more closely linked to suicide or attempted suicide. To this end, the researchers combed through coroners' reports and hospital admission records in six hospitals in the United Kingdom and Wales from 2000 to 2006.

What they found was that TCAs had the overall highest toxicity and the highest rate of fatality compared to SSRIs and all other classes of antidepressants. This was especially true for the TCA drugs Prothiaden (dosulepin) and Silenor (doxepin). Of the SSRIs, Celexa (citalopram) was seen to have the highest toxicity and fatality rate.

On the flip side, terminating antidepressants abruptly can increase the risk of suicide by 500 percent and the risk of attempted suicide by 700 percent. Never stop taking antidepressants suddenly; you will need to talk with your doctor, who will advise you on how to taper off the drug gradually.

Antidepressants can be a life-restoring therapy, but you should be aware of the risks so you can prevent overdoses and get treatment immediately if you recognize the signs. If you or a loved one is taking an antidepressant, call your doctor or get emergency help if the depression seems to be getting worse or is causing suicidal thoughts that may lead to an overdose.