By Edmund Murphy

Last updated: 11 November 2023 & medically reviewed by Dr. Kimberly Langdon

Trazodone is used to treat a variety of mental health conditions and other ailments, and the doses it is prescribed can vary greatly depending on the requirements of the patient. People being treated for major depressive disorder will often be prescribed a higher dose of trazodone than those taking the drug off-label for insomnia.

Trazodone Dosage

Trazodone dosage information

Trazodone is a serotonin receptor antagonist and reuptake inhibitor (SARI) antidepressant prescribed for a variety of mental health disorders as well as a range of other conditions related to brain function.

Doses of trazodone come as an oral tablet that is available in a range of strengths. Trazodone tablets normally start at 150mg strength but some people split these tablets in two for 50mg strength to be taken throughout the day.[1]

Trazodone dosage strengths

Trazodone tablets are short-acting in the US and come in doses of 25mg, 50mg, 100mg, 150mg, and 300mg. Long-acting oral tablets are available in Canada and other parts of the world, such as under the brand name Oleptro, and are available in 150mg and 300mg strengths.[2] Short-acting trazodone has a shorter half-life than long-acting and does not stay in the system as long.

Trazodone 50mg

50mg of trazodone is prescribed to those suffering from milder forms of depression and or anxiety disorders. It may also be prescribed to people suffering from sleep disorders who have been treatment resistant to Valium or other sedatives, as well as those with a history of substance abuse.[1]

Trazodone 100mg

100mg of trazodone will also be prescribed to those suffering from depression and or anxiety and may be used to up doses from 50mg if it is no longer effective.[1]

Trazodone 150mg

Trazodone is most commonly prescribed in 150mg doses for those suffering from major depressive disorder and anxiety disorders. Those being treated with trazodone shouldn’t take more than 150mg throughout the day unless prescribed a higher dose.[1]

Trazodone 300mg

300mg of trazodone is the highest dose prescribed without special measures or in specific situations. Trazodone at 300mg can be broken down into smaller doses to be taken throughout the day or once a day, often in the morning.[1]

Maximum dose of trazodone

The above doses are regularly prescribed by physicians and mental health experts, but there are higher doses. These doses tend to only be used in extreme cases or as part of a long-term treatment plan for mental illnesses.

For outpatient treatment, a maximum of 400mg can be prescribed for major depressive disorder. When a person is hospitalized with mental illness, they may be given up to 600mg a day.[1] Those who meet the requirements for 600mg of trazodone need to have their medical history checked first as trazodone at this dose can potentially cause serious health issues if a person has:

  • A history of severe kidney issues.

  • A history of severe liver issues.

  • Take medications that slow trazodone’s elimination time from the body (such as ketoconazole).

  • Take other drugs that affect serotonin levels in the body, which can increase the risk of serotonin syndrome.

Trazodone dosage by weight

The weight of a patient does not affect the dose of trazodone they should be administered. Unlike other drugs, trazodone does not accumulate in fatty tissue and does not need to be adjusted to account for this. Some people also worry whether trazodone will cause weight gain, but again this issue is rarely of any concern to ongoing treatment.[3]

Trazodone overdose

Trazodone doses of 400mg or more should not be taken unless under close medical supervision. Trazodone overdoses are rare and almost always nonfatal, however having a high level of trazodone in the system, alongside other factors, can cause serious health complications.[4]

Trazodone overdose symptoms include:

  • Breathing problems

  • Irregular heartbeat

  • Coma

  • Constant erection in males

If you are taking a high dose of trazodone and experience any of the above symptoms, contact emergency services at 911 or seek medical assistance.

Trazodone for depression

Trazodone, despite being approved for the treatment of depression is rarely prescribed for that reason. In recent years, selective serotonin reuptake inhibitors (SSRIs) like escitalopram (Lexapro) and sertraline (Zoloft) have become the preferred treatment medication for people suffering from depression. Though rarely used in modern medical practice, it can still be prescribed on occasion.

Trazodone dosage for depression

Trazodone used to treat depression typically needs to be a higher dose than when treating conditions such as insomnia. Doses of trazodone for depression start at 150mg daily, with a max dose of 600mg per day.[5]

When someone is taking a higher dose of trazodone for the treatment of depression, the effects of the drug often take around 2 weeks to take effect and up to 6 weeks before they take full effect.[5] Similarly, someone taking trazodone for depression should reduce their dose gradually over the course of a month to avoid uncomfortable withdrawal symptoms.

Trazodone for anxiety

Trazodone is sometimes prescribed off-label for anxiety, though it is not FDA-approved. Other antidepressant medications such as SSRIs are often preferred as a course of medication for anxiety over trazodone, as are benzodiazepines such as alprazolam. However, the drug is sometimes used as it influences neurotransmitters linked with excitability.

Trazodone dosage for anxiety

To treat anxiety, trazodone can be taken at a dose of 50 mg to 100 mg, two to three times daily. The total daily dosage should not exceed 400 mg.[5]

Trazodone for sleep

One of the known side effects of trazodone when used to treat depression is drowsiness. While sometimes problematic for those being treated for mental health disorders, this side effect makes trazodone an effective off-label treatment for sleep disorders such as insomnia.[7] While there is some debate about the efficacy of trazodone as a sleep aid, many prefer it to other sleeping pills and sedatives as it is considered safer, less addictive, and easier to acquire as trazodone is not a controlled substance.[6]

Trazodone dosage for sleep

When used as a sleeping aid, trazodone is prescribed at various doses depending on the severity of the sleep condition.[6]

  • 50-100mg: One trazodone oral tablet of 50 or 100mg is taken before bedtime

  • 150mg: Doses may be increased if patterns of sleep do not improve

  • 300mg: In rare cases, some people may be prescribed the maximum safe dose to aid with sleep

Off-label trazodone dosage

Trazodone is only FDA-approved for the treatment of depression, and even treating other mental health conditions is technically an off-label treatment. Of these, insomnia and other sleep disorders are the most common conditions that doctors will prescribe trazodone off-label for.

Doctors will also prescribe trazodone off-label to treat other conditions, often as part of a long-term treatment plan. Some off-label prescription doses of trazodone include:

Trazodone dosage for elderly

Trazodone is often prescribed to the elderly for insomnia and other sleep conditions as it has a good safety profile in older people. While it is as safe to use for the elderly as it is for young adults, doses are usually prescribed at 12.5mg daily and gradually increased until a satisfactory sleep pattern is sustained.[8]

Trazodone for dose for children

While the benefits of trazodone for off-label treatment of sleep disorders in adults are well documented, there is little research on its benefits in children. Many pediatric patients with neurodevelopmental disorders (NDDs) such as attention deficit hyperactivity disorder (ADHD) and autism will display insomnia as a symptom of their condition. While trazodone is not currently used regularly for treatment in children with NDDs, studies using doses of 0.35 to 2.1mg of trazodone in children between 6 and 17 have shown positive results.[9]

Trazodone for sundowning

Sundowning is associated with dementia and refers to symptoms of dementia worsening in the afternoon and early evening. For people suffering from dementia and those who care for them, sundowning can be incredibly traumatic. While no medication currently exists to treat sundowning, trazodone, and other antidepressants are often used to manage the symptoms, creating mild sedation and reducing agitation and irritability.[10]

Trazodone for dogs

Various substances have been used to treat both human and animal conditions, such as ketamine for sedation in horses and humans. This rarely includes antidepressants but trazodone has proven effective in helping manage post-surgery stress and anxiety in dogs. Vets will often prescribe trazodone at doses of 1.7 to 19.5mg per day to help canines remain calm and relaxed during the postoperative period.[11]

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