Adrenergic-inhibiting medications

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Category: Medical Options

What is it?

This is a large group of drugs also known as beta blockers, beta-adrenergic blocking agents, beta-adrenergic antagonists, beta antagonists, alpha-adrenergic blocking agents, alpha blockers, alpha-adrenergic antagonists and alpha antagonists.

Adrenergic-inhibiting drugs have been widely used for conditions such as hypertension and cardiac disease. Some evidence is emerging regarding the use of these drugs in PTSD patients.

Those adrenergic-inhibiting medications which have been documented for PTSD include:

  • propranolol (trade names include Inderal and Deralin)
  • clonidine (trade names include Catapres)
  • guanfacine (trade names include Tenex and Intuniv)
  • prazosin (trade names include Minipress,Vasoflex and Hypovase)

How does it work?

The mechanism for adrenergic-inhibitor’s action on PTSD symptoms is not yet well understood. In the brain, messages are passed between nerve cells via a synapse, a small gap between the cells. Naturally occurring chemicals known as neuro-transmitters allow the messages to pass across that gap. It is believed that incorrect levels of neuro-transmitters, such as norepinephrine, lead to symptoms experienced by many PTSD patients. Adrenergic-inhibiting drugs may improve the balance of specific neuro-transmitters in the brain through their ability to block the a-receptors or ß-receptors and thus help to restore normal brain function.

Is it effective?

The evidence for the effectiveness of adrenergic-inhibiting drugs for PTSD is variable and will be discussed below.

  • Propranolol
    More study has been done on the effect of propranolol in the acute phases of traumatic stress disorder than in chronic PTSD. Two small older studies were found for the use of propranolol in PTSD, one which suggested positive effects in veterans with combat-related PTSD and another which showed it to be ineffective for use with Cambodian refugees. Further research is required to establish the effectiveness and safety of propranolol for PTSD patients.
  • Clonidine
    Only a few small studies have been done on the use of clonidine in PTSD, one of which suggested a positive effect in children. Another suggested positive effects when combined with imipramine for Cambodian refugees. Further research is required to establish the effectiveness and safety of clonidine for PTSD patients.
  • Guanfacine
    Very little research has been done on the use of guanfacine in PTSD. A single case report suggested that it was useful for a child with PTSD, however a trial with 29 veterans found that it was ineffective for their combat-related PTSD symptoms. Further research is required to establish the effectiveness and safety of guanfacine for PTSD patients.
  • Prazosin
    Prazosin is a medication which has been trialled for sleep disturbances and nightmares in PTSD.
    The evidence on prazosin is still emerging with very few studies done to date. A systematic review of the effectiveness of prazosin for PTSD was published in 2008 which found that in two studies involving combat veterans with PTSD symptoms, recurrent distressing dreams were significantly reduced in prazosin-treated patients compared to those treated with a placebo.

Are there any disadvantages?

Side effects are not uncommon and differ between the different medications. Those reported include low blood pressure when standing up, dizziness, nausea, headache, drowsiness and gastro-intestinal symptoms. Other side effects are possible and health practitioners should be made aware of any changes.

Where do you get it?

Adrenergic-inhibiting drugs can only be prescribed by registered health practitioners.

What are the evidence limitations?

The evidence base for adrenergic-inhibiting medication use in PTSD is limited. Studies to date have been on small numbers of patients and most has been with combat-related PTSD patients. The methods of diagnosing PTSD were not reported in these reviews.

Recommendations

Prazosin appears to have promise as an effective treatment for PTSD-related sleep disturbance including nightmares, however more evidence is needed. Based on the current evidence, propranolol, clonidine and guanfacine cannot be recommended for the routine treatment of PTSD.
It is important that any drug treatment be provided by a registered health professional, with appropriate assessment and on-going monitoring provided prior and during the course of treatment.

Key References

Cooper, J, Carty, J & Creamer, M 2005, ‘Pharmacotherapy for posttraumatic stress disorder: empirical review and clinical recommendations’, Australian and New Zealand Journal of Psychiatry, vol. 39, pp. 674–682.

Harmon, RJ & Riggs, P 1996, ‘Clonidine for posttraumatic stress disorder in preschool children’, Journal of the American Academy of Child and Adolescent Psychiatry, vol. 35, pp. 1247–1249.

Horrigan, JP & Barnhill, LJ 1996, ‘The suppression of nightmares with guanfacine’, Journal of Clinical Psychiatry, vol. 57 pp. 371.

Kinzie, JD & Leung, P 1989, ‘Clonidine in Cambodian Patients with Posttraumatic Stress’, Journal of Nervous and Mental Disease, vol. 177, pp.546–550.

Kinzie, JD 1989, ‘Therapeutic approaches to traumatized Cambodian refugees’, Journal of Traumatic Stress, vol. 2, pp. 75–91.

Kolb, LC, Burris, BC & Griffiths, S 1984, ‘Propranolol and clonidine in the treatment of the chronic post traumatic stress disorders of war’, in Post-Traumatic Stress Disorder: Psychological and Biological Sequelae, ed. van der Kolk BA. Washington DC, American Psychiatric Press.

Raskind, MA, Peskind, ER, Kanter, ED, et al. 2003, ‘Reduction of nightmares and other PTSD symptoms in combat veterans by prazosin: a placebo controlled study’, American Journal of Psychiatry, vol. 160, pp. 371–373.

Schoenfeld, F, Marmar, C & Neylan, T 2004, ‘Current concepts in pharmacotherapy for posttraumatic stress disorder’, Psychiatric Services, vol. 55, pp.519–531.

Taylor, H, Freeman, M & Cates, M 2008, ‘Prazosin for treatment of nightmares related to posttraumatic stress disorder’, American Society of Health-System Pharmacists, vol. 65, pp.716-22.

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