Health outcome and safety assessment of a fixed dose combination of Amantadine, Paracetamol, Chlorpheniramine maleate, and Phenylephrine introduction in India: A prescription event monitoring study

To assess the likely impact of a fixed dose combination (FDC) of Amantadine, Paracetamol, Chlorpheniramine maleate, and Phenylephrine on the health outcome and safety profile arising from the complementary action of amantadine and other ingredients, we conducted a Prescription Event Monitoring study for patients with suspected Influenza symptoms who were prescribed this FDC in ‘real life clinical settings’ or clinical practice. Between August 2010 and March 2011, Questionnaires were sent to doctors who provided data on the health outcome or safety profile. Sedation and allergy, including rash, were noted in few of the patients. None of the patients reported any major events. Most of the patients (60%) were initiated on FDC therapy within the first 24 hours of symptom onset. Even as a significant proportion of the patients (24.9%) had a concurrent history of allergy / rhinitis including asthma, few of them (4.1%) reported lack of improvement and had to be complemented with antibiotics. The FDC of Amantadine, Chlorpheniramine, Paracetamol, and Phenylephrine was found to be safe and well-tolerated when administered to patients within the first 24 to 48 hours of symptom onset.

Safety profile of rofecoxib as used in general practice in England: results of a prescription-event monitoring study

AIMS

A postmarketing Prescription-Event Monitoring study was undertaken to monitor the safety of rofecoxib, a cyclo-oxygenase (COX)-2 selective inhibitor prescribed in primary care in England.

METHODS

Questionnaires requesting clinical event data were sent to prescribing physicians between February and November 2000, and the data analysed for all events.

RESULTS

There were 15,268 patients identified, mean age 62 years, 67% female. The commonest specified indication was osteoarthritis (24%). Dyspepsia and nausea were the most frequently reported adverse events. A history of dyspeptic or upper gastrointestinal (GI) conditions, recent use of other nonsteroidal anti-inflammatory drugs (NSAIDs), use of selected concomitant gastroirritant drugs (NSAIDs, aspirin, anticoagulants, antiplatelet drugs), or gastroprotective drugs (misoprostol, antacids, proton-pump inhibitors, histamine-2 antagonists), and age (>/= 65 years) modified the risk of having minor GI events. During treatment or within 1 month of stopping, 110 serious GI events were reported (including 76 upper GI bleeds/peptic ulcers, one perforated colon), 101 thromboembolic events, three reports of acute renal failure, one each of Stevens-Johnson syndrome, severe anaphylaxis and angio-oedema.

CONCLUSIONS

Doctors should continue to prescribe NSAIDs including COX-2 selective inhibitors with caution.

The incidence of adverse events and risk factors for upper gastrointestinal disorders associated with meloxicam use amongst 19,087 patients in general practice in England: cohort study

AIMS

Meloxicam is a novel nonsteroidal anti-inflammatory drug (NSAID) which may be associated with fewer adverse upper gastrointestinal events than other NSAIDs because it preferentially inhibits the inducible enzyme cyclo-oxygenase-2 relative to the constitutive isoform, cyclo-oxygenase-1. The aims of the study were to: determine the rate of adverse events associated with meloxicam in general practice, stratify these rates by selected risk factors, and to identify signals of previously unsuspected adverse events associated with meloxicam.

METHODS

As part of the national prescription-event monitoring pharmacovigilance system for newly launched drugs in general practice, all patients prescribed meloxicam in England between December 1996 and March 1997 were identified by the central Prescription Pricing Authority. We sent short questionnaires to all prescribers asking about adverse events experienced within 6 months of the first prescription.

RESULTS

There were 19 087 patients in the study. The rate of dyspepsia during the first month of exposure was 28.3 per 1000 patient-months. There were 33 reports of upper gastrointestinal haemorrhage during treatment (rate: 0.4 per 1000 months). A history of gastrointestinal disorder in the previous year was associated with an increased rate of dyspepsia (rate ratio: 3.0; 95% confidence interval: 2.6, 3.4), abdominal pain (2.1; 1.6, 2.6), and peptic ulcer (4.0; 1.4, 13.2). Prior NSAID use was associated with a 20-30% decrease in the rate of dyspepsia and abdominal pain in patients starting meloxicam, while patients prescribed concomitant gastroprotective agents had a two to three-fold increased rate of dyspepsia, abdominal pain and peptic ulceration. Other rare events were thrombocytopenia (n = 2); interstitial nephritis (n = 1) and idiosyncratic liver abnormalities (n = 1).

CONCLUSIONS

In the absence of gastro-intestinal risk factors the incidence of gastro-intestinal disturbance was low. Such risk factors should be carefully reviewed prior to prescribing meloxicam.

Cough and angiotensin II receptor antagonists: cause or confounding?

AIMS

Cough is one of the most frequent side effects associated with angiotensin converting enzyme inhibitors (ACEIs) but is not thought to be associated with losartan, an angiotensin II receptor antagonist (ARA). This study compares reports of cough with losartan and three ACEIs used in general practice.

METHODS

Studies have been conducted for losartan, and three ACEIs enalapril, lisinopril and perindopril, using the technique of Prescription-Event Monitoring. Patients were identified using dispensed prescription data. Questionnaires were sent to patients' general practitioners 6 months after the date of first prescription. Cases of cough within the first 60 days of treatment with losartan resulting in withdrawal of the drug were followed up with additional questionnaires. Incidence rates for reports of cough were calculated. In order to reduce the impact of carry-over effects, rate ratios were calculated for first reports of cough between days 8 and 60 using losartan as the index drug.

RESULTS

The cohort for each drug exceeded 9000 patients. Age and sex distributions and indications for prescribing the four drugs were similar. Cough was the most frequent reason for discontinuation of losartan and the most frequently reported event in the first month of treatment with this drug. When reports of cough between days 1-7 were excluded, rates of cough were significantly higher for the three ACEIs when compared with losartan (rate ratios 1.5, 4.8 and 5.7, all P<0.03). 101 patients had discontinued losartan due to cough. 91% of these had previously been prescribed an ACEI and 86% had previously experienced ACEI cough.

CONCLUSIONS

Carry-over accounted for the observed excess of reports of cough with losartan. Rates of cough between days 8 and 60 were significantly higher for the three ACEIs compared with losartan. Confounding factors associated with comparative observational cohort studies are discussed.

Age and sex distribution of suspected adverse drug reactions to newly marketed drugs in general practice in England: analysis of 48 cohort studies

AIMS

Little is known about the frequency with which suspected adverse drug reactions are seen by general practitioners after the prescription of newly marketed drugs. We investigated age and sex specific incidence rates of suspected adverse drug reactions recorded by general practitioners in England after the prescription of selected newly marketed drugs.

METHODS

Information was collected from 48 national cohort studies of newly marketed drugs studied by prescription-event monitoring. Questionnaires were sent to prescribers asking for details of events and suspected adverse drug reactions recorded in the patients' notes occurring after the drugs were prescribed.

RESULTS

During the 48 cohort studies, a total of 513608 patients were investigated, of which 221781 (43.2%) were males and 285862 (55.7%) were females. The overall incidence of suspected adverse drug reactions in males was 12.9 per 10000 patient-months of exposure (95% confidence limits 12.3 to 13.5), and in females was 20.6 per 10000 patient-months of exposure (95% confidence limits 19.9 to 21.3). The overall age-standardised relative risk of an adverse drug reaction in females compared with males was 1.6 (1.5-1.7). This sex difference was significant in all age groups above 19 years of age, and was relatively consistent across all age groups (chi2 test for heterogeneity = 9.2, P=0.3). The highest rate of recording in males was in the 50-59 year age group, and in females was in the 30-39 year age group.

CONCLUSIONS

In general practice in England, suspected adverse drug reactions to newly marketed drugs are recorded more often in adults aged between 30 and 59 years of age and are 60% more common in women than in men. The sex difference occurs in all age groups over 19 years of age.

A comparison of ciprofloxacin, norfloxacin, ofloxacin, azithromycin and cefixime examined by observational cohort studies

1. The safety in everyday clinical usage of three 4-quinolone antibiotics, (ciprofloxacin, norfloxacin and ofloxacin), was compared with similar data for azithromycin and cefixime, each agent being examined by Prescription-Event Monitoring (PEM) during the early post-marketing period. 2. In PEM the exposure data are derived from general practitioner prescriptions confidentially provided by the Prescription Pricing Authority. Outcome data are provided by questionnaires (green forms) on which the prescribing medical practitioner records event data. When necessary, further information is obtained from a number of sources which include follow-up of all pregnancies and the patients' life-time medical record. 3. The main outcome measures were demographic information, including the patient's date of birth and sex; the indication for prescribing the drug being monitored; the reason for stopping treatment; the start and stop dates of treatment and the events recorded during and after treatment. 4. The final cohort for each of the five antibiotics exceeded 11000 patients. The only event significantly related to the use of all five antibiotics was nausea/vomiting. This was also the most frequent adverse event causing treatment to be discontinued with norfloxacin, ofloxacin and azithromycin (relevant information was not requested in the studies of ciprofloxacin and cefixime). Vaginal candidiasis was significantly more frequently associated with the use of the three 4-quinolones than with azithromycin and cefixime but it was frequently delayed until the week or two after the cessation of therapy. Within each event, as recorded in these studies, the highest event rates (the number of events per 1000 patients) in the week following the start of therapy were: 9.2 for diarrhoea with cefixime; 4.9 for nausea/vomiting with ofloxacin; 2.4 for rash with azithromycin; 2.2 for abdominal pain with norfloxacin; 1.5 for headache/migraine with ofloxacin; 1.4 for malaise/lassitude with ofloxacin; 1.2 for dizziness with norfloxacin. Uncommon events (reported in less than 1:1000 patients) included rare cases of allergic phenomena, convulsions and pseudomembranous colitis. There were no reports of tendinitis, tenosynovitis or tendon rupture in children but tendon disorders were reported in the two months following the start of treatment in 20 adults. A total of 307 pregnancies were reported. Thirty-eight of the 55 women who received these drugs during the first trimester of pregnancy gave birth to healthy babies. No congenital abnormalities were reported. Apart from one case of unconfirmed pseudomembranous colitis, none of the other 2468 deaths that occurred in these studies was attributed to the antibiotics. 5. These five antibiotics are acceptably safe antimicrobial agents when used in general medical practice. PEM is an effective method for monitoring the safety of recently introduced antimicrobial agents.