Treating Nightmares in Posttraumatic Stress Disorder With Clonidine and Doxazosin

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Charité University Medicine Berlin

Status and phase

Phase 2


Posttraumatic Stress Disorder


Drug: Placebo
Drug: Doxazosin
Drug: Clonidine

Study type


Funder types




Details and patient eligibility


This randomized controlled trial will test the hypothesis that oral Clonidine or Doxazosin improves nightmares (primary outcome), other PTSD symptoms and psychopathology (secondary outcomes) to a greater extent than placebo over a ten week intervention phase in a parallel group design.


189 estimated patients




18 to 65 years old


No Healthy Volunteers

Inclusion criteria

  • Diagnosis of posttraumatic stress disorder (PTSD) according to DSM 5 with a 20 item CAPS-5 total score ≥ 26
  • At least two nightmares a week, an intensity score ≥ 2, with a CAPS-IV B2 (frequency and intensity for the last week) score ≥ 5
  • Men and women between 18 and 65 years of age
  • Written informed consent
  • The patient has the capacity to give consent (He/she is able to understand the nature and anticipated effects/side effects of the proposed medical intervention)
  • The patient is not breastfeeding
  • Women of child-bearing potential must have a negative urine or serum pregnancy test
  • All participants must use highly effective contraception
  • The patient received stable pharmacological medication for at least 4 weeks or at least five times the value of a elimination half-life prior to study baseline (any changes in medication dose or frequency of therapy must be answered with no).

Exclusion criteria

  • Disturbances of cardiac impulse formation and conduction, for example sick sinus syndrome or atrioventricular block second and third degree
  • Bradycardia, with a heart rate less than 50 beats per minute
  • Current major depressive episode and a MADRS score > 34
  • The patient does have a known allergy, hypersensitivity or contraindication against clonidine, doxazosin, or other types of quinazolines
  • History of severe orthostatic hypotension
  • Benign prostatic hyperplasia and concomitant congestion of the upper urinary tract, chronic urinary tract infection or bladder stones, hypotension (for benign prostate hyperplasia only)
  • Either overflow bladder or anuria with or without progressive renal insufficiency
  • Planned cataract surgery (risk of 'Intraoperative Floppy Iris Syndrome')
  • Intake of phosphodiesterase-5-inhibitors
  • Intake of methylphenidate
  • Severe hepatic impairment (ASAT or ALAT greater than two times normal)
  • Acute or unstable medical illness
  • Known HIV- and/or active Hepatitis-B- or Hepatitis-C-infection
  • Current or past malignant illness
  • The patient does have clinically significant abnormalities in 12-lead ECG
  • The patient does have clinically significant laboratory abnormalities
  • Epilepsy
  • Dementia
  • Current substance/alcohol use disorder (≤ 3 months)
  • Psychotic disorder
  • Bipolar disorder
  • Current anorexia nervosa
  • Acute suicidality (any suicidal ideation of type of 5 in the C-SSRS in the past month)
  • Intake of alpha adrenergic agents (Clonidine, doxazosin, or others) within 4 weeks prior to baseline (randomization)
  • Trauma-focused psychotherapy four weeks before the trial
  • Initiation of sleep medication 4 weeks prior to baseline
  • The patient is unwilling to consent to saving, processing and propagation of pseudonymized medical data for study reasons
  • Patients, who may be dependent on the sponsor, the investigator or the trial sites
  • The patient is legally detained in an official institution
  • The patient did participated in other interventional trials during the 3 months before and at the time of this trial

Trial design

Primary purpose




Interventional model

Parallel Assignment


Quadruple Blind

189 participants in 3 patient groups, including a placebo group

Arm Clonidine
Experimental group
Drug: Clonidine
Arm Doxazosin
Experimental group
Drug: Doxazosin
Placebo Comparator group
Drug: Placebo

Trial contacts and locations



Central trial contact

Stefanie Koglin, MD; Stefan Roepke, MD

Data sourced from

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