Desyrel

Aka: Desyrel, Trazodone

1. Indications
   1. Insomnia (as adjunct to SSRI)
   2. Impotence
      1. See Impotence Management for more effective agents
2. Mechanism
   1. Triazolopyridine derivative
   2. Unrelated to Tricyclic Antidepressants
   3. Phenylpiperazine Antidepressant (Serzone prototype)
   4. Serotonin Antagonist and Reuptake Inhibitor (SARI)
      1. Blocks 5-HT-2 postsynaptic receptor
      2. Low dose: Serotonin receptor antagonist
      3. High dose: Serotonin Agonist
      4. Weaker than SSRIs as a Serotonin reuptake inhibitor
3. Pharmacokinetics
   1. Serum Half Life: 4 to 9 hours
   2. Therapeutic plasma level: 800 to 1600
4. Efficacy: Major Depression
   1. As effective as Fluoxetine, Tricyclic Antidepressants
5. Background
   1. Cost: $34 per month (generic)
6. Dosing
   1. Sleep
      1. Dose: 25-100 mg PO qhs
      2. Average: 50 mg PO qhs
   2. Major Depression
      1. Start: 50 to 150 mg per day in divided doses
      2. Effective dose: 400 to 600 mg in divided doses
7. Adverse Effects
   1. Sedation
      1. Limits use as an Antidepressant
      2. Useful in Major Depression with Insomnia
   2. Priapism
      1. See Priapism Management
   3. Serotonin Syndrome
   4. Cardiac Arrhythmia
   5. Orthostatic Hypotension (Dizziness)
      1. Minimize by administering with food
8. Drug Interaction
   1. Increased serum Digoxin level
   2. Increased Phenytoin level
9. Toxicity
   1. Less toxic in Overdose than Tricyclic Antidepressants
   2. Lower Incidence of Anticholinergic Toxicity
10. References
    1. Sundberg (1995) Depression Primary Care, PGM, p. 45-57