Possible pharmacological means of treating renal colic.

The effects of various drugs on the partially obstructed ureter were investigated in a new model experiment which permitted the calculation of peripheral resistance. After the administration of noradrenaline, the local spasm of the ureter in the region of the obstruction was increased and the urinary flow fell. After administration of the alpha-blocker phentolamine and of the beta-receptor stimulant orciprenaline there was a reduction of the peripheral resistance and an increase in urinary flow due to spasmolysis. Because of its lower side-effect rate, phentolamine is worth investigating in further clinical studies.