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Biomedical subjects

T Walley

Publications and source records attributed to T Walley.

14 recordsLinked to original sources

Metipranolol-induced adverse reactions: I. The rechallenge study.

Previously unreported adverse drug reactions can be difficult to detect and it may be even more difficult to establish a cause and effect relationship, particularly if the adverse reactions mimic naturally occurring disease. In a previous paper we reported 29 patients with granulomatous anterior uveitis, blepharoconjunctivitis, periorbital dermatitis, marginal keratitis and elevation in intraocular pressure (IOP), suspected to be caused by metipranolol (Glauline). With the approval of the District Ethics Committee 7 of those patients were rechallenged with metipranolol 0.3% compared to timolol maleate 0.5% in a double blind trial. The 7 metipranolol treated eyes developed an adverse reaction within 14 days. Metipranolol (Glauline) has been conclusively proven to cause granulomatous anterior uveitis, blepharoconjunctivitis and elevation in IOP, adverse effects never previously reported with any of the ophthalmic topical beta-blockers. The multidose preparations of metipranolol (Glauline) in all three strengths 0.1%, 0.3% and 0.6% and the single dose minim preparation of metipranolol 0.6% have now been withdrawn from clinical use in the United Kingdom.

Aged

Different vasodilating mechanisms--different peripheral effects?

Many factors, both local and systemic, are known to influence the caliber of peripheral vessels and regional blood flow. Methods of studying limb blood flow and its alteration by disease and drugs present considerable problems. We compared the effects of a series of antihypertensive drugs on limb blood flow and their functional effects in patients with hypertension and peripheral vascular disease. Results from studies with new antihypertensive drugs such as carvedilol are awaited.

Adrenergic beta-Antagonists

Comparison and reproducibility of transthoracic bioimpedance and dual beam Doppler ultrasound measurement of cardiac function in healthy volunteers.

1. We compared the ease of use and reproducibility of two noninvasive methods, transthoracic electrical bioimpedance (TEB) (BoMed NCCOM3-R7) and non-imaging dual beam Doppler ultrasound (Quantascope--Vital Science), in cardiac output (CO) and stroke volume (SV) measurement in healthy volunteers at rest and during physiological stress, both short term and from day to day. 2. The TEB method was easier to use and not dependent on the operator. The TEB method was more reproducible both in the short term and from day to day. Both devices were able to detect CO and SV changes under physiological stress, but were less reproducible day to day during exercise. 3. At supine rest, the within subject coefficient of variation between time point for TEB was 4.6% for CO and 6.1% for SV, and 7.9% for CO and 7.4% for SV with Doppler. 4. The results from each device showed a linear correlation coefficient (r) of 0.69 for CO (P less than 0.0005) and 0.64 for SV (P less than 0.0005). The correlation coefficient improved to 0.76 (P less than 0.0005) when only changes in CO and SV were considered. There was no systematic difference in the changes detected by the two methods, but the individual variation was wide.

Cardiography, Impedance

Lack of an interaction between propranolol and sumatriptan.

1. The effect of twice-daily dosing with propranolol on the pharmacokinetics and pharmacodynamics of a single oral dose of sumatriptan was investigated in 10 healthy male subjects. 2. Each subject received 7 days dosing with propranolol (80 mg twice daily) plus a single dose of sumatriptan (300 mg orally) on day 7; on another separate occasion, placebo was administered for 7 days plus a single dose of sumatriptan on day 7. There was at least a 7 day washout interval between the two periods of dosing. Pulse and blood pressure were measured up to 10 h after dosing with sumatriptan and blood samples were taken up to 26 h post-dose. 3. Propranolol had no significant effect on any of the derived pharmacokinetic parameters of sumatriptan. The appropriate average parameter values in the presence of propranolol were, respectively: Cmax (120 ng ml-1 vs 126 ng ml-1), tmax (4.5 h vs 3.0 h), AUC (580 ng ml-1 h vs 566 ng ml-1 h), t 1/2,z (1.9 h vs 1.8 h). 4. Propranolol had no significant effect on the pharmacodynamics of sumatriptan, as measured by pulse rate and blood pressure. 5. The results of this study would suggest that no alteration in the sumatriptan dosage will be necessary for migraine patients taking propranolol prophylactic therapy.

Adult

Adverse effects of captopril in hospital outpatients with hypertension.

Hypertensive patients prescribed captopril while attending a hospital hypertension clinic were studied, to identify the benefits of the drug, its adverse effects and factors predisposing to them. One hundred and eighty two patients were followed for a mean of 18 months; 24 received captopril alone, and 158 combinations of captopril and other antihypertensive drugs, especially loop diuretics (91/158), or thiazide diuretics (57/158), or other vasodilators (57/158). The mean final dose of captopril was 67 mg/day. Blood pressure (BP) was effectively controlled in 73% of patients (mean fall in systolic BP 29 mmHg, CI 24 to 34, P less than or equal to 0.001; mean fall in diastolic BP 18 mmHg, CI 16 to 20, P less than or equal to 0.001). Blood urea and creatinine rose slightly in all patients (urea by 0.9 mmol/l [13%], CI 0.5-1.3, P less than or equal to 0.001 and creatinine by 9 mumols/l [8%], CI 4-13, P less than or equal to 0.001). Twenty six patients were withdrawn from captopril therapy: 6 because of poor control of their blood pressure, two because it was no longer necessary and 12 (7.7%) because of extrarenal adverse effects--10 for rashes, one each for gastric upset and impotence. Captopril was withdrawn in a further 6 patients, because of deteriorating renal function. Factors discriminating those at risk of renal dysfunction were high doses of captopril, concomitant high dose diuretic therapy and undiagnosed renovascular disease.

Adult

Nitrite-induced methaemoglobinaemia.

Three patients developed methaemoglobinaemia after eating meat contaminated with excessive nitrites. Diagnosis was delayed in the first two mild cases but was promptly made in the third most severely affected case.

Adolescent