Sympathetic hyperactivation

The sudden cessation of treatment with clonidine, especially when applied in high doses for prolonged periods, has been shown to cause a withdrawal phenomenon, characterised by general symptoms of sympathetic hyperactivation. 

Mid-ventricular takotsubo syndrome (see also p. 313) has also been described in a 75-year-old woman taking anagrelide [139" ]. The authors hypothesized that accumulation of anagrelide, a phosphodiesterase type II inhibitor, had caused major inotropic stimulation and sympathetic hyperactivation in a vulnerable myocardium. 

---