Showing papers by "Stanley Nattel published in 1979"

Mechanism of propranolol withdrawal phenomena.

Abstract: Nine patients on chronic treatment with propranolol for essential hypertension for 3 months or longer were studied after abrupt discontinuation of the drug. Each patient demonstrated transient supersensitivity to the chronotropic effects of isoproterenol, beginning 2--6 days (median 4 days) after propranolol withdrawal, lasting for 3--13 days (median 6 days), with the maximum sensitivity on day 6. A significantly lower dose of isoproterenol was necessary to increase heart rate 25 beats/min on day 6 (median dose 1.2 microgram, range 0.3--3.4 microgram) compared with after day 14, when sensitivity had stabilized (median dose 2.3 microgram, range 1.4--7.6 microgram). Six patients had transient symptoms (headache, chest pain, palpitations and sweating) after abrupt propranolol withdrawal, coinciding with supersensitivity to isoproterenol in five. Transient increases in plasma catecholamines and blood pressures and sustained increases in heart rate occurred during the period of isoproterenol supersensitivity in most patients, and may have contributed to symptoms noted. The delayed onset and potentially long duration of beta-adrenergic supersensitivity after abrupt propranolol withdrawal have important clinical implications.

Therapeutic blood lidocaine concentrations after local anesthesia for cardiac electrophysiologic studies.

Abstract: CLINICAL cardiac electrophysiologic studies are performed to evaluate mechanisms of arrhythmias and their response to therapy.1 2 3 4 5 6 7 8 9 10 Lidocaine, injected to provide local anesthesia be...

Physostigmine in coma due to drug overdose.

Abstract: Twelve patients with coma due to drug overdose were treated with physostigmine salicylate in a double‐blind, placebo‐controlled crossover trial. Three of the 9 patients who had taken drugs without anticholinergic action (methyprylon, barbiturates, ethchlorvynol, benzodiazepines) and 2 of 3 who had taken drugs with anticholinergic action (amitriptyline) showed dramatic decrease of depth of coma after physostigmine. Among patients with non‐anticholinergic overdose, in 10 min physostigmine induced an increase in mean arterial pressure from a mean of 80.3 mm Hg to 103.8 mm Hg (p < 0.05) and in heart rate from a mean of 87.9 beats/min to 98.3 beats/min (p < 0.001). When given to patients with anticholinergic drug intoxication, physostigmine induced a fall in mean arterial pressure from a mean of 105.4 mm Hg to 96.1 mm Hg (p < 0.01) and in heart rate from a mean of 104 beats Imin to 91.3 beats/min (p < 0.10). Physostigmine induced dilation of pupils in all patients with non‐anticholinergic overdose and in none with anticholinergic overdose (p < 0.01). The effects of physostigmine in non‐anticholinergic overdose appear to be due to a nonspecific action on the central nervous system. Physostigmine may also be of value in the differential diagnosis of coma. Its routine use in the treatment of drug‐induced coma is not recommended except in anticholinergic drug overdose unless standard measures fail and artificial mechanical ventilation cannot be provided to patients with severe drug‐induced respiratory depression.

Therapeutic blood lidocaine concentrations after local anesthesia for cardiac electrophysiologic studies

Abstract: CLINICAL cardiac electrophysiologic studies are performed to evaluate mechanisms of arrhythmias and their response to therapy.1 2 3 4 5 6 7 8 9 10 Lidocaine, injected to provide local anesthesia before insertion of the electrode catheter, can affect the results of such studies if substantial blood concentrations are achieved. This study was designed to measure lidocaine concentrations in patients undergoing cardiac electrophysiologic studies. Materials and Methods Seventeen patients were studied after written informed consent was obtained. Lidocaine solution (1 per cent, without epinephrine) was injected subcutaneously into one or both groins before insertion of two to four transvenous electrode catheters. Intravascular injection was avoided by aspiration before each . . .