Sympatholytic
A sympatholytic (sympathoplegic) drug is a medication that opposes the downstream effects of
Mechanisms of action
Antiadrenergic agents inhibit the signals of
Another way to inhibit adrenergic receptor signaling is by blocking
For neurotransmitters to be released, they first must be stored in
Other drugs are preferentially toxic to sympathetic neurons. One method of obtaining such specificity is to exploit drugs that are substrates for a transporter preferentially expressed on sympathetic terminals, such as the
Medical uses
Hypertension
Many antiadrenergic agents used as
- Centrally acting
- Prazosin (α1 inverse agonist)
- Rescinnamine (ACE inhibitor)
- VMATinhibitor)
- Rilmenidine (imidazoline receptor agonist)
- Ganglion-blocking
- nicotinic receptorantagonist)
- ganglion type receptorantagonist)
- Peripherally acting
- Magnesium-ATPaseinhibitor)
- α1 antagonist)
- Doxazosin (alpha blocker)
- Beta blockers
- Non-selective agents
- Alprenolol
- Bucindolol
- Carteolol
- Carvedilol (has additional α-blocking activity)
- Labetalol (has additional α-blocking activity)
- Nadolol
- Penbutolol (has intrinsic sympathomimetic activity)
- Pindolol (has intrinsic sympathomimetic activity)
- Propranolol
- Sotalol
- Timolol
- β1-selective agents
- Acebutolol (has intrinsic sympathomimetic activity)
- Atenolol
- Betaxolol
- Bisoprolol
- Celiprolol
- Esmolol
- Metoprolol
- Nebivolol
- β2-selective agents
- Butaxamine (weak α-adrenergic agonist activity) - No common clinical applications, but used in experiments.
- ICI-118,551 Highly selective β2-adrenergic receptor antagonist - No known clinical applications, but used in experiments due to its strong receptor specificity.
- Non-selective agents
Anxiety
Beta blockers
There is clear evidence from many controlled trials in the past 25 years that beta blockers are effective in anxiety disorders, though the mechanism of action is not known.[3]
Some people have used beta blockers for performance type social anxiety, or "stage fright." In particular, musicians, public speakers, actors, and professional dancers, have been known to use beta blockers to avoid stage fright and tremor during public performance and especially auditions. The physiological symptoms of the fight/flight response associated with performance anxiety and panic (pounding heart, cold/clammy hands, increased respiration, sweating, etc.) are significantly reduced, thus enabling anxious individuals to concentrate on the task at hand. Stutterers also use beta blockers to avoid fight/flight responses, hence reducing the tendency to stutter.
Since they promote a lower heart rate and reduce tremor, beta blockers have been used by some Olympic marksmen to enhance performance, though beta blockers are banned by the International Olympic Committee (IOC).[3] Although they have no recognizable benefit to most sports, it is acknowledged that they are beneficial to sports such as archery and shooting. A recent, high-profile transgression took place in the 2008 Summer Olympics, where 50 meter pistol silver medalist and 10 meter air pistol bronze medalist Kim Jong-su tested positive for propranolol and was stripped of his medal.
Alpha2 adrenergic agonist
Kinzie and Leung prescribed the combination of clonidine and imipramine to severely traumatized Cambodian refugees with anxiety, panic and PTSD.[7] Global symptoms of PTSD were reduced among sixty-six percent and nightmares among seventy-seven percent. Guanfacine produces less sedation than clonidine and thus may be better tolerated. Guanfacine reduced the trauma-related nightmares.[8]
Alpha blockers
Prazosin is an
See also
References
- ^ "Dorlands Medical Dictionary:sympatholytic".
- S2CID 31949.
- ^ S2CID 24742562.
- PMID 26504586.
- ^ Kaplan HI, Sadock B (1998). Kaplan and Sadock's Synopsis of Psychiatry (8th ed.). Baltimore: Lippincott Williams & Wilkins.
- PMID 8824068.
- S2CID 38938044.
- PMID 8752021.
- ^ "Prazosin: Biological activity". IUPHAR. International Union of Basic and Clinical Pharmacology. Retrieved 3 June 2016.
- PMID 12562588.
External links
- Sympatholytics at the U.S. National Library of Medicine Medical Subject Headings (MeSH)