Coming full circle in pharmacovigilance: communicating safety information to patients through patient package inserts

Optimal drug therapy requires that the patient should be informed adequately, unequivocally and in timely fashion. Patient package inserts (PPIs) have an important facilitating role to play in this respect. Patients' confidence in the benefit of a drug treatment and their fear of its side effects are strong determinants of their adherence to that treatment. Yet, the European PPI format does not allow a discussion of the treatment's benefits, which results in an unbalanced focus on side effects. This serious shortcoming may significantly interfere with a patient's compliance. In addition, prescribers are often unaware of the content of the PPI of the products they are prescribing. To rectify this situation, the development is proposed of annotated PPIs providing the scientific background to the PPI message. In conclusion, European PPIs need to be improved. The patient should be informed of the expected benefit of a drug treatment, its likelihood and the expected time course of the effect, and not only of side effects and interactions, which constitutes the present focus. Moreover, prescribers need to be informed about the content of the PPIs for the medicines they prescribe.

Why there is a need for pharmacovigilance

Not everything is known about a medicine when it receives its licence for marketing. The merits of a new drug, balancing its beneficial and its untoward effects, become only established after sufficient experience has been gained from its use in real practice. Part of the reason for this is that our extensive phase III clinical trials fail to detect some side-effects. Why is this so? Three groups of reasons may be envisaged, namely (1) our trials lack the power to detect rare side-effects; (2) some side-effects do not occur in the context of clinical trials; (3) some side-effects, though common enough, fully or partly escape detection due to lack of suitable detection techniques. The following presents a closer look at these three mechanisms.

Postmarketing study of the use of flunarizine in vestibular vertigo and in migraine

OBJECTIVE

This international postmarketing observational study of flunarizine was designed to evaluate, in routine clinical practice, the risk/benefit ratio of flunarizine in its approved indications, namely prophylaxis of migraine and treatment of vertigo. Comparator drugs were propranolol in migraine and betahistine in vertigo. The study was carried out by 498 general practitioners in Belgium, The Netherlands and Germany, whose participation had been requested by mail. In total 3186 patients were entered: 1601 in the two migraine cohorts and 1585 in the two vertigo cohorts.

RESULTS

In the migraine study, treatment results with propranolol tended to be somewhat better than those with flunarizine, but a selection bias cannot be excluded. There was no clear difference regarding efficacy between flunarizine and betahistine in the vertigo study. The safety evaluation focused on extrapyramidal symptoms (EPS) and depression. Overall, EPS were noted in only four patients, two in the vertigo-betahistine and two in the migraine-flunarizine cohort. A total of 70 patients developed depressive symptoms (34 in the flunarizine and 24 in the propranolol migraine cohorts, but only 7 in the flunarizine and 5 in the betahistine vertigo cohorts). Patients with migraine were clearly more prone to depression than patients with vertigo, regardless of their treatment. Additional risk factors for depression were a history of depression, and, in the migraine flunarizine cohort, a high number of previous migraine treatments.

Post-marketing cohort study comparing the safety and efficacy of flunarizine and propranolol in the prophylaxis of migraine

A comparative post-marketing surveillance study of the safety and efficacy of flunarizine and propranolol in the treatment of migraine was carried out. General practitioners in Belgium and the Netherlands each recruited patients for whom they would prescribe one of the study medications in the normal course of their treatment and recorded all medical events on follow-up forms for up to 8 months. A total of 1601 migraine patients were enrolled; 838 in the flunarizine cohort and 763 in the propranolol cohort. Propranolol was somewhat better than flunarizine in reducing the severity of migraine attacks, although this may have been due to a selection bias. Discontinuations of therapy due to events considered likely to be treatment-related were mostly due to the recognized side effects of the two drugs. As regards the occurrence of depressions, a total of 58 patients had depressive events, 34 in the flunarizine cohort and 24 in the propranolol cohort. Whereas migraine itself appears to be associated with an increased risk of depression, the number of previous migraine treatments was shown to be an additional risk factor for the development of depression in patients receiving flunarizine as was a history of depression. Overall, there was no appreciable difference in the risk/benefit ratio between flunarizine and propranolol.

Risk of selected serious cardiac events among new users of antihistamines

This retrospective cohort study examined the risk of selected serious cardiac events in new users of either astemizole or sedating antihistamines identified from the COMPASS Ohio Medicaid population of approximately 1 million active lives per year (1986-1992). (COMPASS is an automated claims database.) There were 15,585 patients in the astemizole group and 30,105 in the sedating antihistamines group. Reports of ventricular arrhythmia or sudden death occurring within 30 days of the first antihistamine claim were identified from Medicaid claims. Medical records were obtained and reviewed by a clinician for validity of diagnoses. Records for patients without a full 30 days of follow-up were sought in the National Death Index. Death certificates were obtained for all patients who died within 30 days of the first antihistamine claim. Of 53 cases identified, 6 were in the astemizole group and 47 in the sedating antihistamines group. The relative risk for all selected cardiac events among astemizole users compared with sedating antihistamine users was 0.25 (95% confidence interval: 0.11 to 0.58), and this estimate did not change substantially when adjusted for age; sex; race; recent history of cardiovascular disease, arrhythmias, asthma/pulmonary disease, or malignant neoplasms; or concomitant prescription of other drugs. This study provided no evidence that astemizole users are at increased risk for cardiac events in the first month of use when compared with users of sedating antihistamines.

Levamisole, the story and the lessons

The history of the use of levamisole in man is summarized, from its start as an anthelmintic in the early sixties, through its world-wide recognition as an immunotropic agent especially in the seventies and early eighties, and its return to clinical prominence in 1989-90 as an effective adjuvant treatment for operable colon cancer. The knowledge accumulated from experimental tumour models and from clinical use in various types of cancer, supplemented with the recent evidence obtained from large-scale controlled trials in resectable colon cancer is reviewed. It is speculated that we may not have seen the end of levamisole story yet; also, the role of serendipidity in drug research is emphasized.

The role of the gut in migraine: the oral 51-Cr EDTA test in recurrent abdominal pain

Sixteen children with recurrent abdominal pain (or: "recurrent syndrome"), regarded as migraine equivalent in childhood, were submitted to the 51-Cr EDTA gut permeability test. The results were compared with those obtained in 10 healthy young adults and in 11 control children. The gut permeability in the recurrent syndrome was significantly higher than in healthy adults and control children (p less than 0.0006): The following results were obtained: 4.83 +/- 0.40 (mean +/- SEM) in the children with recurrent abdominal pain, and 2.35 +/- 0.24 2.51 +/- 0.21 in the healthy young adults and control children, respectively. The implications of these findings as far as migraine is concerned, are discussed.

Aromatase inhibition by R 76713: experimental and clinical pharmacology

R 76713 is a new non-steroidal compound which inhibits aromatase in vitro and in vivo with a potency of at least 1000-fold that of aminoglutethimide. In male cynomolgus monkeys peripheral conversion of labeled androstenedione to estrone is decreased by 85%, 4-5 h after a single intravenous dose of 0.003 mg/kg of R 76713, without altering steroid metabolic clearance rates. In rats fed a sodium-depleted diet for 3 weeks, plasma levels of aldosterone and plasma renin activity remain unchanged 2 h after a single oral dose of up to 20 mg/kg of R 76713. This confirms previous data on the selectivity of R 76713 for aromatase inhibition as compared to inhibition of other enzymes involved in steroid biosynthesis. In male volunteers, a single oral dose of 5 or 10 mg of R 76713 lowers median plasma estradiol levels from 70 pM to the detection limit of the assay (30 pM) 4 and 8 h after intake, whereas no important changes are detected after placebo administration. In 15 premenopausal female volunteers receiving a single oral dose of 20 mg of R 76713, mean plasma estradiol levels decrease from 415 pM (before) to 179, 149 and 185 pM respectively 4, 8 and 24 h after intake whereas they remain above 380 pM after placebo (n = 7).

The sensorium of the migraineur

The occurrence of perceptual disturbances in migraineurs, particularly during the headache-free interval, has been scrutinized rather rarely. This subject was studied via a mail survey in 134 patients presenting perceptual changes before or during their migraine attacks. The patients had to complete a 5-part questionnaire covering history, events before, during as well as after the attack, and the attack-free interval. Sensory alterations during the headache-free interval were not reported by 36.6% of the patients. Alterations of equilibrium and/or spatial orientation, mainly susceptibility to motion sickness, were present in 47.8%, increased sensitivity to cold or heat in 40.3%, intolerance of tight clothes or being touched in 34.3%, altered visual function in 32.8%, changes in olfactory acuity in 31.1%. These percentages show that these 5 types of interictal sensory disturbances may not be rare in migraineurs. The exact frequency of these symptoms and how they correlate with perictal phenomena, sex, age and disease characteristics has to be further studied.

Onset of action of various migraine prophylactics

Four studies were pooled to study the onset of action of three pharmacologically different migraine prophylactics: flunarizine, pizotifen and propranolol. Inter-drug differences in reduction of baseline attack frequency were subjected to analysis of variance. At months 1, 2, and 3 the inter-drug differences in number of patients showing a first 50% decrease in attack rate were subjected to the Chi-square test. Both tests showed that there were no significant differences in onset of action between the three drugs. It is concluded that migraine responds to flunarizine and to other commonly used prophylactics in a similar way and with similar kinetics.

Hepatic cytochrome P450-mediated oxidation function in migraine

Hepatic cytochrome P450-dependent oxidation is deficient in 5% to 10% of the Caucasian population. A similar percentage seems to suffer from migraine. The hypothesis was tested that an oxidation deficiency possibly relevant to potential dietary triggers plays a role in the pathogenesis of migraine. In 37 migraine sufferers and 26 controls age- and sex-matched to 26 of these patients, debrisoquine hydroxylation following an oral dose of 10 mg was employed as a marker of oxidation status, determined by calculating the metabolic ratio (MR): urinary debrisoquine/urinary 4-hydroxydebrisoquine. MR was similarly distributed in migraineurs and controls. Three subjects in each group were poor metabolizers (MR greater than 30, versus normal range, 0.1-12). MR in patients did not depend on type of migraine (common versus classic), attack frequency, the presence of trigger factors, smoking or a history of adverse reactions or sensitivity to medicines.

The effect of sabeluzole (R 58735) on memory retrieval functions

In a first double-blind, placebo-controlled parallel experiment, 20 volunteers with a median age of 45 years were treated for 1 week with either sabeluzole (R 58735) or placebo. Before and after the treatment period, they were subjected to a Selective Reminding Procedure in which a 20-word list had to be learned. No differences between the two groups were seen for total recall, short-term retrieval, total long-term retrieval, random long-term retrieval and long-term storage. However, a significant improvement in consistent long-term retrieval (cLTR) was seen for the subjects treated with sabeluzole. This effect was restricted to the group of the poor performers, i.e. those with a baseline cLTR of 50% or less. In a second experiment, 12 healthy elderly volunteers with a median age of 59 years were subjected to the same test procedure. They were treated with sabeluzole in a single-blind fashion. Again the cLTR improved significantly in the group of poor performers. It was thus confirmed that sabeluzole ameliorates retrieval functions and primarily so in poor performers.

The effect of R 58 735 (Sabeluzole) on memory functions in healthy elderly volunteers

The effects of chronic treatment (5 mg b.i.d. for 2 days followed by 10 mg b.i.d. for 5 days) with R 58 735 on human memory functions were studied in healthy elderly (age greater than or equal to 50 years) volunteers in a double-blind placebo-controlled study. Serial learning of nonsense syllables was better under R 58 735, and relearning 1 week after termination of the treatment was superior to relearning of similar material initially learned under placebo. Free recall of nonsense syllables was significantly better when these were learned under active compound. Proactive inhibition induced by consecutive presentation of word lists was attenuated by R 58 735. Short-term memory functions, retrieval accuracy from semantic memory and unprepared reaction times were unchanged. R 58 735 ameliorated both learning and recall in conditions of age-related mild hypofunction in healthy volunteers. The compound seems to have had positive effects on encoding and consolidation of new material.

Some comments on the use of statistics in the evaluation of drug trials in migraine

Statistical aspects need particular attention in reporting on drug studies in migraine. It is important to report on all patient and disease characteristics which have contributed to the diagnosis and on all variables used for the evaluation of the result; the use of median values, accompanied by the extremes, is recommended in this context. Comparability of the study groups should be examined and possibly repeated after exclusion of the defaulters, if their number is substantial. As regards the presentation of the results, it does not suffice to give p values only: the magnitude of the response should be given and the use of techniques estimating the reliability of this magnitude (e.g. confidence intervals) and/or its reproducibility (e.g. power calculations) is recommended. An analysis of three unrelated groups of migraineurs demonstrates that most pertinent variables show a non-Gaussian distribution, and this includes the distribution of treatment results. For this reason, the use of nonparametric tests is advocated.

Flunarizine, the vestibular system and migraine

The vestibular function was extensively investigated in 75 patients suffering from migraine. Pathological findings were present in 62 patients (82.6%). With the exception of position nystagmus, vestibular abnormalities were not related to migraine characteristics. Fifty-six patients were treated with flunarizine 10 mg daily for three months. A favourable effect on headache was obtained in 44 patients (78.5%). Flunarizine therapy influenced significantly gaze nystagmus and position nystagmus. The latter tended to be related to anti-migraine efficacy. Other electronystagmographic parameters were not substantially influenced. The authors assume that the vestibular abnormalities in migraine are side phenomena, the clinical relevance of which, at least during the headache-free phase, is not yet well understood.

Migraine and cerebral hypoxia: a hypothesis with pharmacotherapeutic implications

It is postulated that a migraine attack is a specific reaction pattern to an episode of focal cerebral hypoxia. This hypothesis holds that any type of focal brain hypoxia (and thus not only a vasospasm) may provoke a migraine attack. Indeed, as hypoxia is a result of an imbalance between energy supply and energy use, the former can be decreased and/or the latter be increased. Spreading cortical depression, leading to the aura, is believed to be another consequence of brain hypoxia occurring in classical migraine. There are no other genuine differences between classical and common migraine, according to the cerebral hypoxia theory. The latter theory may improve our understanding of the mode of action of antimigraine drugs. Certain calcium entry blockers have a direct protective effect on brain hypoxia, but some other pharmacotherapeutic approaches may also prevent cerebral hypoxia via an effect on brain metabolism, vasomotion or platelet behavior.

Bioavailability and saturation of the presystemic metabolism of oral lorcainide therapy initiated in three different dose regimens

The feasibility of giving a supplementary starting dose of the antiarrhythmic drug lorcainide, in order to minimalize the impact of the extensive, but saturable first-pass metabolism, was evaluated. Twenty-five adult patients were given 100 mg lorcainide tablets according to one of 3 different dosage schedules: Eight patients took one tablet at 0, 12 and 24 h, 8 took 1 tablet at 0, 1, 12 and 24 h and 9 took 1 tablet at 0, 2, 12 and 24 h. Levels of lorcainide and its metabolite, nor-lorcainide, during treatment were determined by gas-liquid chromatography. The results show that giving a second tablet 1 or 2 h after the first may produce faster saturation of the pre-systemic metabolism of lorcainide in the liver.

Brain hypoxia: the turning-point in the genesis of the migraine attack?

The hypothesis postulates that a brief episode of focal cerebral hypoxia occurs in every attack of migraine. Clinical biochemical and technical (EEG and CT scans) evidence is summarized suggesting that cerebral hypoxia is seen as the turning-point in the pathogenesis of the attack. It may be provoked by different mechanisms in different patients; the potential role of decreased oxygen supply and of increased oxygen need are reviewed and excess sympathetic drive is considered a potential key mechanism in a majority of patients. Whether or not focal hypoxia leads to a genuine migraine attack, depends largely upon the quality of the whirlpool of biochemical, vascular and hematological changes that follow the hypoxic episode. These changes are discussed and it is concluded that those which have been reported to occur during migraine attacks could be due to a preceding hypoxic event. Finally, the hypoxia viewpoint is confronted with some popular theories about the pathogenesis of migraine. It is found that the other points of view are compatible with the hypoxia hypothesis.

Levamisole and immunotherapy: some theoretic and practical considerations and their relevance to human disease

The major features of levamisole immunotherapy are distilled from experiences gained so far. The biochemical effects of levamisole are discussed in view of its effects on T lymphocytes and phagocytes. Potential indications for levamisole treatment are classified after Jerry et al. as immune deficiencies or as immune dysregulation syndromes (such as rheumatoid arthritis and cancer). After a scrutiny of investigations in cancer patients, the conclusion emerges that, in a subsection of patients, mainly those with poor prospects, levamisole improves the prognosis after effective chemotherapy, radiotherapy or surgery when given in time and in an appropriate dosage.

Adjuvant therapy with levamisole in resectable lung cancer

In view of the discouraging results that have been obtained so far with the use of cytotoxic chemotherapy as an adjunct to surgery, a double-blind placebo-controlled evaluation of the adjuvant use of levamisole was conducted in 211 resectable lung cancer patients, following these patients for 2 years after their operation. Levamisole (or the placebo) was given for 3 days every 2 weeks and the dose level ranged 1.1--3.8 mg/kg per day (a fixed dose of 3 x 50 mg was given to all patients). It appeared that recurrences and carcinomatous deaths had occurred significantly less often in patients who had received a high dose (i.e., 2.1--3,8 mg/kg: patients weighing 70 kg or less) but not in the patients who received a lower dose. Patients who had more advanced cancers at the time of surgery seemed to have profited more from the treatment, but the results did not seem to depend upon the histologic type of the tumor or on the immune status of the patients as estimated from the skin test reactivity at the start. There was also suggestive evidence that levamisole may be more effective in preventing hematogenous dissemination than in inhibiting recurrences in the lung or the mediastinal tissues. Levamisole, if dosed adequately, appears to be a very suitable adjuvant treatment in resectable lung cancer patients as judged from its efficacy and its lack of troublesome side-effects.

Time in chemo-immunotherapy models: an absolute or a relative variable? Lessons from the levamisole experience

An analysis is presented of the findings from the available studies in several cancer models, where 2.5-20 mg/kg levamisole was given in combination with different types of cytostatic drugs. It appears that in chemo-immunotherapy experiments it may be preferable to measure time variables (increase in life span, timing of chemotherapy and of immunotherapy) as a per cent of the median survival time of the untreated controls instead of using time as an absolute measure (in days). As regards the study of levamisole in chemo-imnmunotherapy models, the increase in life span by the cytostatic alone seems to be the most important variable studied here. An "optimal" protocol for the evaluation of levamisole is proposed based upon all the findings of this analysis.

Final results of a multicenter placebo-controlled levamisole study of resectable lung cancer

Two hundred and eleven patients with resectable lung cancer have been treated in a double-blind clinical investigation with either levamisole (50 mg three times a day) or a placebo given in 3-day courses starting 3 days before the operation and repeated every 2 weeks. The study was terminated after all patients had been in the trial for 2 years. The dose of levamisole used in this study appears to be sufficient only for patients weighing less than or equal to 70 kg and, therefore, future studies should make use of an individually adapted dose. Such a treatment is expected to prolong both the disease-free interval and the survival time without causing major side effects in a significant number of patients. This result is achieved primarily by an inhibition of hematogenous dissemination and occurs especially in those patients who had more advanced tumors at the time of the resection.

Adjuvant treatment with levamisole in cancer: a review of experimental and clinical data

Animal and human studies of adjuvant treatment with levamisole in cancer are reviewed and discussed. From the animal data it is concluded that the activity of levamisole is dose-dependent, more effective on slow-growing tumors, affects metastasis formation, preferentially is best when levamisole is used as an adjuvant to the usual cytoreductive treatments and that tumor enhancement is not expected. Clinical findings are put into perspective of the animal data and the most appropriate clinical situations are indicated.