By Edmund Murphy

Last updated: 21 March 2024 & medically reviewed by Dr. Celeste Small

Trazodone is an antidepressant commonly prescribed to treat depression, anxiety, and any combination of the two. While trazodone is often a safe form of treatment for most people, there are some side effects from the drug as well as the potential for abuse and addiction that can make it dangerous.

Key takeaways:

  • Like selective serotonin reuptake inhibitor (SSRI) antidepressants, SARIs like Trazodone work by changing the brain’s chemical balance of the mood-enhancing neurotransmitters serotonin by both blocking the receptor and inhibiting the uptake of it as well.

  • hose who are prescribed trazodone are advised to carry on with the course of medication in the recommended dose even if symptoms do not ease in the first 6 weeks.

  • Serotonin syndrome (SS) occurs when a person has an irregular amount of serotonin in their body. This most commonly occurs when a person is taking one or more serotonergic drugs including SARI (trazodone), SSRI, MAOI, and TCA antidepressants.

Trazodone blue pill with writing

What is trazodone?

Trazodone Hydrochloride is a form of antidepressant that belongs to the serotonin receptor antagonist and reuptake inhibitor (SARI) group. Like selective serotonin reuptake inhibitor (SSRI) antidepressants, SARIs work by changing the brain’s chemical balance of the mood-enhancing neurotransmitters serotonin by both blocking the receptor and inhibiting the uptake of it as well.

The medication is prescribed to treat mental health conditions such as depression, anxiety, and any combination of the two. It is also sometimes prescribed for those suffering from poor sleep or restlessness conditions such as insomnia as one of its side effects causes tiredness.[1]

How long does trazodone take to work?

Trazodone is often prescribed for depression and will often become effective between 1 and 2 weeks after the first dose if taken as prescribed. However, it may take up to 6 weeks for the drug to start taking full effect. 

Those who are prescribed trazodone are advised to carry on with the course of medication in the recommended dose even if symptoms do not ease in the first 6 weeks. Additionally, patients may at first start to experience a worsening of symptoms in the first couple of weeks. If you are prescribed trazodone and feel like your symptoms are getting worse, speak to your doctor or mental health expert.

Trazodone side effects

There are several side effects associated with trazodone use, ranging from mild to severe. Those who use trazodone may expect to experience some of the more mild side effects of the drug, with most symptoms dissipating over time.

Some of the common side effects of trazodone include:

  • Swelling

  • Sleepiness

  • Dizziness

  • Diarrhea

  • Stuffy nose

  • Weight loss

  • Blurred vision

  • Xerostomia (or dry mouth)

If these side effects do not begin to fade over the first few weeks, speak to your physician or prescribing doctor. Trazodone has also been linked to weight gain, much like other forms of antidepressants.

Serious side effects of trazodone

The more serious side effects can be dangerous and potentially life-threatening. It is vital that you notify a medical professional or call 911 if you begin to experience any of the following:

  • Suicidal ideation/suicide attempts

  • Worsening depression

  • Worsening anxiety

  • Agitation 

  • Restlessness

  • Panic attacks

  • Insomnia

  • Increased aggression 

  • Mania (inability to stop moving or talking)

  • Unusual changes in behavior

Trazodone and serotonin syndrome

Serotonin syndrome (SS) occurs when a person has an irregular amount of serotonin in their body. This most commonly occurs when a person is taking one or more serotonergic drugs including SARI (trazodone), SSRI, MAOI, and TCA antidepressants.[5]

The symptoms of serotonin syndrome may appear mild at first but can be life-threatening. SS can dramatically increase body temperature and may lead to seizures. Other symptoms of serotonin syndrome include: 

  • Agitation

  • Confusion or trouble thinking

  • Hallucinations (seeing or hearing something that isn’t there)

  • Problems with coordination

  • Fast heart rate

  • Tight muscles

  • Trouble walking

  • Nausea

  • Vomiting

  • Diarrhea

  • Eye pain

  • Changes in your vision, such as blurred vision or visual disturbances

  • Swelling or redness in or around your eye

  • Irregular or fast heartbeat

  • Low blood pressure.

  • Dizziness or fainting

  • Unusual bruising or bleeding

  • Erection that lasts longer than 4 hours

  • Hyponatremia (low sodium in your blood).

  • Headache

  • Weakness

  • Confusion

  • Trouble concentrating

  • Memory problems

  • Feeling unsteady when you walk

Trazodone overdose

Trazodone overdoses are rare but there have been reported cases. The risk of a trazodone overdose is greatly increased if the drug is taken with other substances, especially central nervous system (CNS) depressants. Symptoms of trazodone overdose include:[7]

  • Respiratory System

  • Difficulty breathing

  • Respiratory arrest

  • Cardiovascular System

  • Chest pain

  • Irregular heartbeat

  • Low blood pressure

  • Decreased heart rate

  • Nervous System

  • Dizziness

  • Drowsiness

  • Headache

  • Lack of coordination

  • Insomnia

  • Seizures

  • Coma 

  • Tremor

  • Gastrointestinal

  • Vomiting

  • Nausea

A trazodone overdose can also lead to serotonin syndrome, as mentioned above.

Trazodone interactions

Taking trazodone in conjunction with certain drugs can cause adverse side effects. Always run through your full list of prescribed medications and drug use history with your doctor before starting a course of trazodone treatment. 

Drugs that cause side effects when taken with trazodone include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, or warfarin (a blood thinner). May increase the risk of excessive bleeding when taken with trazodone.

  • Central nervous system (CNS) depressants such as pentobarbital and secobarbital. Trazodone may make your response to barbiturates and other CNS depressants stronger.

  • Depression drugs, such as citalopram, fluoxetine, paroxetine, sertraline, venlafaxine, duloxetine, and St. John’s wort. Taking these drugs alongside trazodone may increase the risk of serotonin syndrome.

  • Digoxin. Taking trazodone with digoxin may increase the levels of digoxin in your body. This could increase your risk of side effects from digoxin. These include impaired vision, vomiting, dizziness, and irregular heart rate.

  • Phenytoin. Taking trazodone with phenytoin may increase the levels of phenytoin in your body. This could increase your risk for side effects from phenytoin. These include constipation, changes in mood, impaired balance, and confusion.

  • Ritonavir or Ketoconazole. The level of trazodone in your body may increase if you take it with ketoconazole, ritonavir, or other drugs that increase levels of trazodone. This can increase your risk of side effects from trazodone including serotonin syndrome and vision problems.

Trazodone and alcohol

Alcohol is a CNS depressant that can exacerbate the drowsiness effects of trazodone. This can mean that day-to-day activities such as manual labor or driving become hazardous. Speak to your doctor about the risk of taking trazodone and drinking alcohol and whether it is safe for you to do so.

Trazodone addiction

Addiction to antidepressants such as trazodone is not common and the DEA does not consider the drug to be addiction-forming. However, people may still choose to abuse the substance and if prolonged abuse of the drug in high amounts occurs then a person may become dependent on it. 

Dependence on a substance occurs due to the brain’s chemical levels becoming unbalanced due to prolonged or high exposure. In the case of trazodone, the brain becomes used to the levels of serotonin being produced and is no longer able to maintain the same levels naturally. Once dependence on trazodone has formed, the person taking it will not be able to function or feel normal without it. The degree of negative consequences to a person's life due to dependence is how addiction is measured and diagnosed. 

Again, dependence on trazodone is extremely rare and often only occurs when someone is abusing the substance alongside other CNS affecting drugs such as opioids or stimulants.

Trazodone withdrawal

Withdrawal symptoms usually present themselves when trying to stop using a substance after a prolonged period of use. Over time, the brain adjusts to the chemical balance created by taking drugs such as trazodone and can cause side effects known as withdrawal symptoms when use stops. 

Withdrawal symptoms can be very uncomfortable and potentially dangerous. Before deciding to stop taking trazodone, consult with your doctor first as they may suggest tapering off the drug in order to minimize withdrawal symptoms.

Symptoms of trazodone withdrawal include:

  • Agitation

  • Anxiety

  • Confusion

  • Dizziness

  • Headache

  • Trouble sleeping

  • Irritability

Like other antidepressants, stopping trazodone use suddenly has the potential to cause rebound depression or anxiety, with often worse symptoms than those the drug was originally prescribed to treat. If you stop taking trazodone and begin to feel depression, suicidal ideation, or anxiety again then speak to a doctor urgently.

Commonly asked questions about trazodone

Here are some of the questions we get asked most often about trazodone.

How long does trazodone stay in your system

The length of time a substance like trazodone will stay in your system depends on a variety of factors, including the drug's half-life and the person's age and body mass.

Read here to find out more about how long trazodone stays in your system.

Is trazodone a controlled substance?

All forms of medication, including trazodone, are regulated under the Controlled Substances Act which classifies them into different schedules depending on their potential for abuse and medical properties. 

For example, Schedule I drugs have a high potential for abuse and no medical benefit, and Schedule V drugs have medical use and no reported risk of abuse and addiction.

Does trazodone cause weight gain?

A commonly reported side effect of antidepressants is fluctuating weight. Some antidepressants can cause weight loss while others have been shown to lead to the patient gaining weight. Read here to find out if trazodone causes weight gain and why.