ISSN:
1432-1041
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary 1. The metabolic fate of intravenous and oral propranolol has been studied after single doses in man using 14C labelled propranolol. — 2. After oral administration there is virtually complete absorption and peak blood levels of propranolol and 4-hydroxy propranolol (a beta blocking metabolite) are seen at about 1 1/4 h after administration. Studies in normal subjects confirm that the maximum degree of beta blockade occurs at this time. — 3. Following intravenous administration, no 4-hydroxy propranolol is seen and the possible reasons for this are discussed. — 4. Excretion of the administered radio-active dose is mainly in the urine, with only 1%–4% of the administered radio-activity appearing in the faeces after both intravenous and oral dosing. — 5. The major metabolite so far identified in the urine is naphthoxylactic acid, which accounts for approximately 20% and 40% of oral and i.v. doses respectively. — 6. The greater proportion of radio-activity excreted in the urine (30–60% of the administered dose) is as yet unidentified although it may be a conjugate of propranolol. The level of total blood radio-activity following both intravenous and oral propranolol is very much higher than that of either propranolol or 4-hydroxy propranolol. The major portion of this blood radio-activity appears to be the same as the unidentified urinary metabolite. — 7. Following intravenous doses the decline of pharmacological response roughly parallels that of propranolol concentration in the plasma, and does not correlate with the plasma concentration of the unidentified metabolite.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00420338
