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Biomedical subjects

P C Waller

Publications and source records attributed to P C Waller.

At least 19 recordsLinked to original sources
PubMed1997

Severe cystitis associated with tiaprofenic acid.

OBJECTIVE: To review the UK spontaneous reports of urinary disorders associated with tiaprofenic acid and other non-steroidal anti-inflammatory drugs (NSAIDs) and put them into context of the usage of these preparations in the UK. METHODS: Suspected adverse drug reaction (ADR) reports of urinary disorders associated with tiaprofenic acid and other NSAIDs received by the UKs spontaneous ADR reporting scheme were analysed. RESULTS: Between 1982, when tiaprofenic acid was introduced in the UK, and August 1994, 69 cases of cystitis were reported, with a further 32 reports describing related urinary symptoms including frequency, dysuria and haematuria. Only eight cases of cystitis were reported for all other NSAIDs. The duration of treatment with tiaprofenic acid before the onset of urinary symptoms varied markedly (range 2 days to > 3 years). In patients in whom a drug-induced cause was suspected and the drug was stopped promptly, recovery usually occurred within weeks. However, many patients continued on long-term treatment with tiaprofenic acid and underwent extensive investigations to determine the cause of their urinary symptoms. On cystoscopy and biopsy, the findings were similar to interstitial cystitis. Most patients with chronic cystitis recovered after withdrawal of tiaprofenic acid, but some patients had surgery before the drug was stopped. CONCLUSION: Tiaprofenic acid can cause severe cystitis. These reports highlight the importance of taking a full drug history in patients with unexplained chronic cystitis. Tiaprofenic acid should be stopped immediately in all patients developing urinary symptoms.

Adverse Drug Reaction Reporting Systems↗
PubMed1996

A comparison of the post-marketing safety of four selective serotonin re-uptake inhibitors including the investigation of symptoms occurring on withdrawal.

1. We have addressed the question of whether there is a 'serotonin withdrawal syndrome' by analysis of spontaneous reports of suspected adverse drug reactions (ADRs) associated with four SSRIs. A comparison of the post-marketing safety profiles of the four SSRIs has also been made. 2. The UK database of ADRs was examined for reactions associated with fluoxetine, fluvoxamine, paroxetine and sertraline. The safety profiles of the four SSRIs were similar. However, withdrawal reactions with paroxetine constitute a greater proportion of reports (5.1%) than with the other SSRIs (0.06-0.9%). They have been reported more often with paroxetine (0.3 reports per thousand prescriptions) than with sertraline and fluvoxamine (0.03), and least often with fluoxetine (0.002). 3. Descriptions of withdrawal reactions received and further details of 217 reports of withdrawal reaction with paroxetine obtained by mailing a questionnaire to the reporting doctor were examined. Withdrawal symptoms were diverse but most commonly comprised dizziness, paraesthesia, tremor, anxiety, nausea and palpitation. They usually occurred after 2 days and lasted for an average of 10 days. There was no evidence of a physical drug dependency syndrome. 4. Symptoms different from the previous depressive illness occur after discontinuing an SSRI, and are reported most often with paroxetine. Paroxetine is the most pharmacologically specific of the SSRIs, but it is not clear whether the reactions constitute a 'serotonin withdrawal syndrome'.

1-Naphthylamine↗
PubMed1995

Appetite suppressants and primary pulmonary hypertension in the United Kingdom.

OBJECTIVE: Amphetamine-like appetite suppressants, particularly fenfluramines, have been implicated in the aetiology of primary pulmonary hypertension. At one specialist centre in France 20% of patients with primary pulmonary hypertension had been exposed to fenfluramine. The prevalence of primary pulmonary hypertension associated with fenfluramines and other appetite suppressants in the United Kingdom is unknown. This study was performed to measure prior exposure to appetite suppressants in patients with primary pulmonary hypertension. SETTING: Heart lung transplantation centres in England. PATIENTS: United Kingdom residents with proven primary pulmonary hypertension referred for consideration of heart lung transplantation. METHODS: Case surveillance study, obtaining data from the hospital and general practitioner's notes and directly from the patients or their relatives. RESULTS: 55 patients were identified. Drug histories were available from hospital records in all patients, from the general practitioner's notes in 51, and from the patients or relatives in 44. Of these, 3 female patients had been exposed to appetite suppressants (2 fenfluramine, 1 diethylpropion): 2 have since died. In each case exposure was brief and apparently predated the development of symptoms by several years. CONCLUSIONS: Exposure of patients with severe primary pulmonary hypertension to fenfluramine and other appetite suppressants is uncommon in the United Kingdom unlike in France, where most of the cases associating primary pulmonary hypertension with fenfluramine use have originated. This may reflect more conservative prescribing of these agents in the United Kingdom.

Adult↗
PubMed1993

Comparison of captopril, hydralazine and nifedipine as third drug in hypertensive patients.

The antihypertensive, biochemical and adverse effects of captopril, hydralazine, nifedipine and placebo were compared in 160 patients with BP inadequately controlled by atenolol 100 mg daily plus bendrofluazide 5 mg daily. Treatments were given for up to 12 weeks. Beta-blocker and thiazide were continued unchanged. All three active drugs reduced supine BP relative to placebo; mean BP changes attributable to active treatment (95% confidence intervals): captopril 13.4/10.3 mmHg (0.6/4.0 to 26.2/16.6), hydralazine 15.0/10.0 mmHg (1.7/3.4 to 28.3/16.6), nifedipine 16.8/8.1 mmHg (4.0/1.8 to 29.6/14.4). There were no significant differences between the agents. Results for erect BP were similar. Target BP (< 140/95 mmHg) was achieved more frequently on captopril (33%), hydralazine (29%) and nifedipine (17%) than on placebo (10%). Compared with the other treatments captopril increased serum potassium concentration (P = 0.01), and hydralazine reduced serum cholesterol concentration (median changes: captopril -0.2 mmol/l, hydralazine -0.8 mmol/l, nifedipine -0.2 mmol/l, and placebo +0.2 mmol/l, P < 0.001). Overall, side-effects did not differ significantly between the groups; withdrawals resulting from adverse reactions: captopril 15%, hydralazine 24%, nifedipine 22%, and placebo 3% (chi 2 = 8.2, P = 0.04). Captopril, hydralazine and nifedipine did not differ significantly in efficacy and tolerability when added to atenolol and bendrofluazide. However, there were trends in favour of captopril, on which drug the highest proportion of patients had their BP controlled and the lowest proportion were withdrawn because of side-effects. Thus, of the drugs tested, captopril appears to be the best option as third drug in hypertension.

Adrenergic beta-Antagonists↗
PubMed1993

Effects of atenolol withdrawal in patients on triple antihypertensive therapy.

The objective of this study was to examine the contribution of beta-blockade to antihypertensive treatment regimens including an angiotensin converting enzyme inhibitor or a calcium antagonist. The effects on BP control, adverse events, and plasma active renin concentration of removing atenolol from standard triple therapy (bendrofluazide and atenolol together with captopril or nifedipine) were assessed in a double-blind, randomised, parallel-group study, of eight weeks' duration in 46 patients from the Glasgow Blood Pressure Clinic. Blood pressures rose in patients randomised to placebo-atenolol compared with those who continued active-atenolol although the difference did not achieve statistical significance. However, the proportion of patients with controlled blood pressure (supine systolic BP < 140 mmHg plus supine diastolic BP < 95 mmHg) fell from 31% to 0% over the study period in patients given placebo-atenolol. There was a trend for BP control to deteriorate most when atenolol was withdrawn from nifedipine treated patients, but the 95% confidence intervals for the difference from captopril-treated patients were wide. Few side-effects were seen and these did not differ quantitatively between the study groups. Plasma active renin concentration was initially higher in captopril-treated patients, and increased on withdrawal of atenolol in both groups. Our findings suggest that beta-blockers make a clinically relevant contribution to treatment regimens including angiotensin converting enzyme inhibitors or calcium antagonists when given as part of standard triple antihypertensive therapy.

Adult↗
PubMed1992

Review of company postmarketing surveillance studies.

OBJECTIVES: To review postmarketing surveillance studies sponsored by the pharmaceutical industry since the introduction of voluntary guidelines in 1987 and to evaluate their contribution to monitoring drug safety. DESIGN: Retrospective analysis of the information submitted to the Medicines Control Agency on postmarketing surveillance studies. SETTING: United Kingdom. MAIN OUTCOME MEASURES: Study designs, projected and actual sample sizes, provision of interim and final reports, number of suspected serious adverse reactions reported, identification of new drug safety hazards. RESULTS: 31 studies had been conducted under the guidelines, of which 27 were prospective and four retrospective. Nine studies had at least one comparator group, the remainder were uncontrolled. The median projected sample size for the studies was 5600 patients. Only five studies had achieved at least 75% of the projected sample size. 11 studies had been abandoned, predominantly because of difficulties in recruitment, and 15 were ongoing. One study had identified an important new safety hazard. CONCLUSIONS: Company postmarketing surveillance studies have made only a limited contribution to the assessment of drug safety, principally because of weak study designs and difficulties in recruitment. The guidelines require modification to take this experience into account.

Drug Industry↗
PubMed1990

Blood pressure response to percutaneous transluminal angioplasty for renovascular hypertension: an overview of published series.

OBJECTIVE: To evaluate the efficacy and safety of transluminal angioplasty in the treatment of renovascular hypertension. DESIGN: Overview of 10 published case series. SETTING: Mostly tertiary referral centres. PATIENTS: 691 Patients treated by angioplasty for renovascular hypertension, 464 for atherosclerotic stenosis, 193 for fibromuscular stenosis, and the remainder mainly for post-transplant stenosis. The inclusion criteria varied considerably between studies. INTERVENTIONS: Percutaneous transluminal renal artery angioplasty (successful or attempted); prophylaxis against restenosis in most cases. Policies on antihypertensive drug treatment and follow up varied. MAIN OUTCOME MEASURES: Blood pressure response as defined in the individual papers, with each patient classified as either cured, improved, or failed. Each study used a different definition of improvement in blood pressure. Complication rates. RESULTS: Follow up data were available for 670 patients. The procedure was technically successful in 611 patients (88%). The overall cure rate for hypertension was 24% (163 patients) and a further 43% (286) were "improved." There were large and significant variations between studies in the rate of technical success and also the blood pressure outcome. In each series patients with fibromuscular lesions, had a higher cure rate than those with atherosclerotic lesions (overall cure 50% v 19% odds ratio 3.9, 95% confidence interval 2.6 to 6.0). Complications were reported in 63 (9%) patients and three patients died (0.4%). CONCLUSIONS: The evidence for the value of angioplasty in treating renovascular hypertension has serious limitations. Angioplasty for fibromuscular disease seems to be worth while, but for atherosclerotic lesions the benefit appears to be small and its efficacy needs to be compared with medical therapy in randomised trials. These findings emphasise the importance of early formal evaluation of new therapeutic techniques.

Angioplasty, Balloon↗