As such, metabolism by liver is the assumption for those with impaired renal function, as supported by increased frequency of known side effects of orthostatic hypotension and sedation. History
In 1986, guanfacine was approved by the FDA for the treatment of hypertension under the brand name Tenex (Drugs@FDA). In 2010, guanfacine was approved by the FDA for the treatment of attention deficit hyperactivity disorder for people 6–17 years old. It was approved for ADHD by the European Medicines Agency under the name Intuniv in 2015. It was added to the Australian Pharmaceutical Benefits Scheme for the treatment of ADHD in 2018. Brand names
Brand names include Tenex, Afken, Estulic, and Intuniv (an extended release formulation). Research
Guanfacine has been studied as a treatment for post-traumatic stress disorder (PTSD). Evidence of efficacy in adults is limited, but one study found positive results in children with comorbid ADHD. It may be also useful in adult PTSD patients who do not respond to SSRIs.Results of studies using guanfacine to treat Tourettes have been mixed.Guanfacine has been investigated for treatment of withdrawal for opioids, ethanol, and nicotine. Guanfacine has been shown to help reduce stress-induced craving of nicotine in smokers trying to quit, which may involve strengthening of prefrontal cortex meditated self-control. References
External links
"Guanfacine". Drug Information Portal. U.S. National Library of Medicine.
Pathophysiology
The cause of takotsubo cardiomyopathy is not fully understood, but several mechanisms have been proposed. It is well documented that elevated catecholamine levels have been implicated in the vast majority of TTS cases. Theories suggest a link between brain activation of stress-related biochemicals and the effects these chemicals have on areas of the heart. More specifically, adrenal stimulation by the sympathetic nervous system has been noted in cases ranging from physical events such as ischemic stroke, to emotional events such as depression or loss of a loved-one. How these increased levels of catecholamines act in the body to produce the changes seen with TTS is not clearly understood. Research supports the widely-held understanding that microvascular dysfunction and coronary vasospasm caused by a rapid influx of catecholamines to cardiac myocytes results in apical stunning and transient cardiomyopathy. Microvascular dysfunction/Transient vasospasm: Some of the original researchers of takotsubo suggested that multiple simultaneous spasms of coronary arteries could cause enough loss of blood flow to cause transient stunning of the myocardium. Other researchers have shown that vasospasm is much less common than initially thought. It has been noted that when there are vasospasms, even in multiple arteries, that they do not correlate with the areas of myocardium that are not contracting. However, the idea of coronary artery vasospasm is still believed to contribute to the TTS disease process. The theory of vasospasm is not easily separated from that of microvascular dysfunction and in fact, microvascular dysfunction could explain vasospasticity.