In Collaboration With

THERAPEUTICS

Brands

• Remeron
• see index for additional brand names

Generic?

• Yes

Class

• Alpha 2 antagonist; NaSSA (noradrenaline and specific serotonergic agent); dual serotonin and norepinephrine agent; antidepressant

Commonly Prescribed For

• (bold for FDA approved)
• Major depressive disorder
• Panic disorder
• Generalized anxiety disorder
• Posttraumatic stress disorder

How The Drug Works

• Boost neurotransmitters serotonin and norepinephrine/noradrenaline
• Blocks alpha 2 adrenergic presynaptic receptor, thereby increasing norepinephrine neurotransmission
• Blocks alpha 2 adrenergic presynaptic receptor on serotonin neurons (heteroreceptors), thereby increasing serotonin neurotransmission
• This is a novel mechanism independent of norepinephrine and serotonin reuptake blockade
• Blocks 5HT2A, 5HT2C, and 5HT3 serotonin receptors
• Blocks H1 histamine receptors

How Long Until It Works

• Actions on insomnia and anxiety can start shortly after initiation of dosing
• Onset of therapeutic actions in depression, however, is usually not immediate, but often delayed 2 to 4 weeks
• If it is not working within 6 to 8 weeks for depression, it may require a dosage increase or it may not work at all
• May continue to work for many years to prevent relapse of symptoms

If It Works

• The goal of treatment is complete remission of current symptoms as well as prevention of future relapses
• Treatment most often reduces or even eliminates symptoms, but not a cure since symptoms can recur after medicine stopped
• Continue treatment until all symptoms are gone (remission)
• Once symptoms gone, continue treating for 1 year for the first episode of depression
• For second and subsequent episodes of depression, treatment may need to be indefinite
• Use in anxiety disorders may also need to be indefinite

If It Doesn’t Work

• Many patients only have a partial response where some symptoms are improved but others persist (especially insomnia, fatigue, and problems concentrating)
• Other patients may be nonresponders, sometimes called treatment-resistant or treatment-refractory
• Consider increasing dose, switching to another agent or adding an appropriate augmenting agent
• Consider psychotherapy
• Consider evaluation for another diagnosis or for a comorbid condition (e.g., medical illness, substance abuse, etc.)
• Some patients may experience apparent lack of consistent efficacy due to activation of latent or underlying bipolar disorder, and require antidepressant discontinuation and a switch to a mood stabilizer

Best Augmenting Combos for Partial Response or Treatment-Resistance

• SSRIs, bupropion, reboxetine, atomoxetine (use combinations of antidepressants with caution as this may activate bipolar disorder and suicidal ideation)
• Venlafaxine (“California rocket fuel”; a potentially powerful dual serotonin and norepinephrine combination, but observe for activation of bipolar disorder and suicidal ideation)
• Modafinil, especially for fatigue, sleepiness, and lack of concentration
• Mood stabilizers or atypical antipsychotics for bipolar depression, psychotic depression or treatment-resistant depression
• Benzodiazepines
• Hypnotics or trazodone for insomnia

Tests

• None for healthy individuals
• May need liver function tests for those with hepatic abnormalities before initiating treatment
• May need to monitor blood count during treatment for those with blood dyscrasias, leucopenia, or granulocytopenia
• Since some antidepressants such as mirtazapine can be associated with significant weight gain, before starting treatment, weigh all patients and determine if the patient is already overweight (BMI>25.0–29.9) or obese (BMI>30)
• Before giving a drug that can cause weight gain to an overweight or obese patient, consider determining whether the patient already has pre-diabetes (fasting plasma glucose 100–125 mg/dl), diabetes (fasting plasma glucose >126 mg/dl), or dyslipidemia (increased total cholesterol, LDL cholesterol and triglycerides; decreased HDL cholesterol), and treat or refer such patients for treatment, including nutrition and weight management, physical activity counseling, smoking cessation, and medical management
• Monitor weight and BMI during treatment
• While giving a drug to a patient who has gained >5% of initial weight, consider evaluating for the presence of pre-diabetes, diabetes, or dyslipidemia, or consider switching to a different antipsychotic