Specific bradycardic agent; analog of clonidine, q.v. Prepn: H. Sthle et al., DE 1958201; eidem, US 3708485 (1971, 1973 both to Boehringer, Ing.); eidem, J. Med. Chem. 23, 1217 (1980). Clinical pharmacology: D. W. G. Harron et al., J. Cardiovasc. Pharmacol. 4, 213 (1982). Mode of action study: J. S. Millar, E. M. Vaughan Williams, Lancet 1, 1291 (1981). HPLC determn in human plasma: U.-W. Wiegand et al., J. Chromatogr. 223, 238 (1981). Clinical pharmacokinetics: eidem, J. Cardiovasc. Pharmacol. 4, 59 (1982). Hemodynamic effects in angina or infarction: M. L. Simoons, P. G. Hugenholtz, Eur. Heart J. 5, 227 (1984). Review of pharmacology and potential therapeutic uses: D. W. G. Harron, R. G. Shanks, ibid. 6, 722-729 (1985).