The link between sunshine and phototoxicity of sparfloxacin

AIMS

To test the association between reporting rates for sparfloxacin-induced phototoxicity and sunlight u.v. exposure, and the effects of regulatory action.

METHODS

The reporting rates for phototoxicity with sparfloxacin to the French Pharmacovigilance System or to the Drug Manufacturer were compared with concurrent national mean u.v. exposure obtained from Météo-France, before and after the regulatory restrictions and warnings.

RESULTS

There were 371 severe phototoxic reaction reports during the first 9 months of marketing (reporting rate of 0.4 per thousand treated patients), approximately four to 25 times that reported for other fluoroquinolones. The reporting rate correlated highly (r = 0.873, P < 0.001) with the mean monthly u.v. exposure from sunlight (from Météo-France). Regulatory action including warnings for physicians, and restricted indications dramatically decreased the number of reports, but not the reporting rate.

CONCLUSIONS

This is the first demonstration of a strong association between sunlight exposure in a population and drug-induced phototoxicity. Regulatory action had no effect on the reporting rate (individual exposed patient risk), though it solved the public health issue.

Adverse drug reactions with fluoroquinolones

The French system of drug surveillance has analysed the notifications of adverse drug reactions (ADRs) to fluoroquinolones since they were launched. Their frequency ranges from 1/15,000 to 1/208,000 case per days of treatment. Cutaneous diseases and tendon disorders predominate in France whereas cutaneous effects and neuropsychiatric disorders are predominant in the UK; tendon disorders take up only the 5th position. Among the most unexpected ADRs are the following: -shock represents 33 of the anaphylaxis reactions which range from 1/5.6 x 10(6) to 1/4.4 x 10(5) case per days of treatment. -acute renal failure is rare: one case/80,000 patients treated by ciprofloxacin to 1/320,000 by norfloxacin. The pathophysiology is not well known. Tendon ruptures represent 81 cases for 921 notifications of tendon disorders which are related in decreasing order to pefloxacin 1/23,130 case per days of treatment, ofloxacin, norfloxacin and ciprofloxacin 1/779,600 case per days of treatment. Age and corticosteroids increase the risk of tendon rupture.

Penetration of pefloxacin and its desmethyl metabolite into the uroepithelium after a 800-mg single oral dose in human patients

Penetration of pefloxacin into the uroepithelium was studied in 20 patients (10 men and 10 women) receiving a single oral dose of 800 mg. Samples of serum, urine, and uroepithelium were taken 1.8 h (mean) after the dose. Pefloxacin and its active metabolite, norfloxacin, were assayed by liquid chromatography, and the microbiologically active compounds were quantified by a microbiological assay. Both procedures were correlated (r > 0.7); nevertheless, slight differences detected in concentrations depended on the levels of norfloxacin achieved in the biological samples. The serum and tissue concentrations were higher than the concentration of bactericide (4 micrograms.ml-1), except in one case. The uroepithelium concentration of pefloxacin was proportional to the serum concentration (r = 0.79). The urinary concentrations ranged from 1.2 micrograms.ml-1 to 82.4 micrograms.ml-1. The mean norfloxacin/pefloxacin ratios were 3% in serum, 8% in uroepithelium, and 44% in urine. The mean uroepithelium/serum concentration ratios were 1 for pefloxacin and 2.3 for norfloxacin. This result shows that, at a time close to that of the maximum concentration, there is good penetration of pefloxacin and norfloxacin into the uroepithelium.

Double-blind randomized multicentre trial of acamprosate in maintaining abstinence from alcohol

A prospective placebo-controlled, randomized double-blind study of Acamprosate at two dose levels in alcohol-dependent patients followed up for 12 months was performed. After detoxification, each of the 538 patients included was randomly assigned to one of three groups: 177 patients received placebo, 188 received Acamprosate at 1.3 g/day (low dose group) and 173 received 2.0 g/day (high dose group) for 12 months. This was followed by a single blind 6 month period on placebo. The patients' mean age was 43.2 +/- 8.6 years. Their mean daily alcohol intake was high (nearly 200 g/day) and of long duration (9.5 +/- 7.1 years). Abstinence figures followed the order high dose > low dose > placebo. The difference was significant at 6 months (P < or = 0.02) but not at 12 months (P = 0.096). The number of days of continuous abstinence after detoxification was 153 +/- 197 for the high-dose group versus 102 +/- 165 for the placebo group (P = 0.005), with the lose-dose group reporting 135 +/- 189 days. Clinic attendance was significantly better in the Acamprosate groups than in the placebo group at 6 months (P = 0.002) and 12 months (P = 0.005). During the 6-month post-treatment period, no increased relapse rate or residual drug effect was observed. The side effect profile for Acamprosate was good compared with controls with only diarrhoea being reported more frequently (P < 0.01). This study confirms the pharmacological efficacy of Acamprosate and its good acceptability. As an adjunct to psychotherapy, this study supports the inclusion of Acamprosate in a strategy for treating alcoholism.

Influence of food intake on the pharmacokinetics of a sustained release formulation of sodium valproate

The effect of food intake on the pharmacokinetics of DEPAKINE CHRONO 500 mg (Sanofi, France), a sustained release formulation containing 333 mg sodium valproate and 145 mg valproic acid, was studied in 12 young healthy female volunteers. Relative to fasting conditions (F), when the tablet was given at the midpoint of the breakfast (NF), the maximum concentration (F: 34.6 +/- 8.9 micrograms ml-1 and NF: 40.9 +/- 7.3 micrograms ml-1; p = 0.014) and the mean cumulative amount absorbed up to time 6 h (F: 76.3 +/- 11.8% and NF: 90 +/- 10.4%; p = 0.0099) were significantly increased. Nevertheless, the extent of absorption (F: 46.7 +/- 9.9 mg l-1; NF: 48.7 +/- 7 mg l-1) was not significantly affected. There was no change in the area under the curve (1129 micrograms.h ml-1), in the mean residence time (28 h), or in the elimination half-life (16 h). On the basis of this study, the question as to whether DEPAKINE CHRONO should be administered to subjects in the fasting or non-fasting state would not appear to be a major consideration when deciding on the regimen.

[Stereoselective protein binding of non-steroidal anti-inflammatory agents. Pharmacological implications]

Non steroidal anti-inflammatory drugs (NSAIDs) contain a chiral carbon alpha to carboxyl function. Except for naproxen, chiral NSAIDs are marketed for clinical use as racemate, ie an equimolar mixture of the two enantiomers R(-) and S(+). However, in vitro studies have shown that the anti-inflammatory activity exists almost solely in the S form. The unbound fraction is able to diffuse into tissues and to reach sites of action. It represents also the pharmacological active form. Stereoselective protein binding studies carried out at various concentrations of NSAIDs and albumin are used to evaluate the free fraction of the active enantiomer. Two optical isomers do not interact in the same manner with proteins and this binding stereoselectivity depends on NSAID and experimental conditions. Thus, it seems difficult to predict the in vivo free concentration of each enantiomer and protein binding experiments should be achieved taking into account the physiopathological parameters which influence this biological process. This enantioselectivity is determinant for the pharmacokinetic properties and could be responsible of the parameters variation obtained for each enantiomer. It could explain the variability in response to NSAIDs too. In fact, the anti-inflammatory effect is directly function of the free concentration of the S isomer. To correlate the NSAID dose with its activity, it should be better to determine this free fraction in the site of action, in particular in the synovial fluid. But the clinical response, as for example the antalgic effect, remains very far from the pharmacological activity, ie the cyclooxygenase inhibition.

Determination of zopiclone in plasma using column liquid chromatography with ultraviolet detection

A reversed-phase liquid chromatographic method with ultraviolet detection for the determination of zopiclone in plasma is described. It is rapid, sensitive, reproducible and linear over a wide range. The method was used to study plasma zopiclone concentrations in a case of acute intoxication after oral ingestion of 300 mg of the drug. The plasma level was 1600 ng/ml 4.5 h after the dose and the elimination half-life was 3.5 h.

Plasma and cerebrospinal fluid concentrations of paracetamol after a single intravenous dose of propacetamol

Since the antipyretic and probably the analgesic effects of paracetamol are, at least in part, centrally mediated, its plasma and cerebrospinal fluid (CSF) concentrations were measured in 43 patients with nerve-root compression pain. Each subject was given a short i.v. infusion of 2 g propacetamol, a prodrug which is hydrolysed to paracetamol within 7 min. Single blood and CSF samples were drawn concomitantly in each patient at intervals between 20 min and 12 h. Maximum CSF drug concentrations were observed at the 4th hour, subsequent concentrations exceeding those in plasma. The elimination half-life of paracetamol calculated from pooled data was shorter in plasma (2.4 h) than in CSF (3.2 h). The time-course of paracetamol in CSF may parallel that of analgesic effect.

Automated determination of disopyramide and N-monodealkyldisopyramide in plasma by reversed-phase liquid chromatography with a column switching system

A rapid and simple column liquid chromatographic method involving a column switching system for the determination of disopyramide and its N-monodealkyl metabolite (NMD) in plasma is described. The deproteinized plasma is applied to an automated system. Purification and concentration were performed using a precolumn connected to a six-position valve; analytical separation was done on-line using a cyano reversed-phase column with a mobile phase consisting of 10 mmol/l trimethylamine (pH 2.5, adjusted with phosphoric acid)-acetonitrile-tetrahydrofuran (78:20:2, v/v/v). Absorbance was measured at 265 nm, with a minimum detectable amount of disopyramide and NMD of 0.1 micrograms/ml. The method can be applied to drug monitoring and pharmacokinetic studies.

Plasma thiamine concentrations after intramuscular and oral multiple dosage regimens in healthy men

A novel liquid chromatographic method for the determination of thiamine in plasma has been developed and has been used to study plasma thiamine concentrations after multiple dosage regimens for 11 days. The method involves purification, concentration and analytical separation of thiochrome on-line, using a switching column system. Ten healthy men were given 500 mg thiamine i.m. once a day (Group 1) and ten were given 250 mg p.o. every 12 h (Group 2). The times to reach steady state (7 and 5.6 days for Groups 1 and 2, respectively) were not different (P greater than 0.05). The mean elimination half-life was 1.8 days. The mean minimum steady-state concentration after the oral regimen (23 micrograms.l-1) was 78% of that after the intramuscular regime (29 micrograms.l-1).

Effect of plasma exchange on flumequine pharmacokinetics: comparison with control kinetics

The effect of plasma exchange (PE) on the pharmacokinetics of flumequine (Apurone) was studied in eight patients receiving a single oral dose of 800 mg. The maximum concentration (38 micrograms/ml) and time to maximum concentration (2.6 h) values were not significantly altered by PE beginning 3 h after administration of flumequine. There was no change in the terminal elimination half-lives (6.6 h), in the steady-state volume of distribution (29 L), or in the apparent plasma clearance (2.5 L/h). By contrast, PE decreased the mean residence time by 30% (14.3 +/- 4.1 h without PE; 9.88 +/- 1.36 h with PE; p less than 0.05). The amount of flumequine extracted by PE (72 mg) was proportional to the plasma concentration at the beginning of the exchange. The elimination half-life during PE (3.15 +/- 1.23 h) decreased by 40%. Renal clearance (0.3 L/h) was not affected. PE only partially modifies the pharmacokinetics of flumequine administered in a single oral dose before PE.

[International reporting of adverse drug reactions. Final report of CIOMS ADR Working Group]

Under the auspices of the Council for International Organizations of Medical Sciences, a working group composed of representatives of seven multinational pharmaceutical manufacturers and six regulatory authorities developed and implemented a standardized method for reporting post-approval adverse drug reactions (ADR). The method is based on a set of uniform definitions and procedures and a single reporting form, and has been demonstrated to be feasible and effective. Regulators and manufacturers, in establishing requirements and systems for reporting of adverse drug reactions, should consider adopting this method.

Pharmacovigilance. The French system

The French system of drug surveillance (pharmacovigilance) is a combination of mandatory reporting and intensive hospital surveillance. The Regional Centres are decentralised but coordinated through a national network. An algorithm index is used to assess the relationship between drugs and adverse effects. The adverse reactions alert system is produced by the compilation and analysis of the cases entered in a data bank (8062 in 1988) and by the analysis of queries from general practitioners (20,000 in 1988). The duties of the centres are also to provide information, analyse data and to improve the safe use of drugs.

Differences in sodium salicylate protein binding in serum and synovial fluid from patients with a knee effusion

Protein binding of sodium salicylate in synovial fluid and in serum from 23 inpatients with rheumatic diseases were studied, ex vivo, by equilibrium dialysis. Scatchard model with two classes of sites was used as a mathematical tool. At therapeutic concentrations, protein binding of sodium salicylate was significantly higher in serum than in synovial fluid. The ratio of areas under the curves for bound concentrations for synovial fluid to that for serum was 0.867. This difference was attributed to the hypoalbuminemia observed in the synovial fluid; for a given molar ratio of drug to albumin, or in other words, for the same amount of available drug per mole of albumin. The number of sites occupied was the same in the two biological media.

[A 30-month study of the calls to the Regional Drug Monitoring Center in Lorraine (Nancy)]

For over a period of 30 months, all the questions to the French "Centre de Pharmacovigilance" of Nancy Lorraine have been analysed. The University Hospital of Nancy is by for the main caller (65%) and the suspicion of adverse drug reaction represents 61% of all the questions. Gastrointestinal and hepatic disorders, cardiovascular drugs arouse the greatest number of questions. Comparison with results previously published by some French Pharmacovigilance Centres points out some regional particularities.

Identification and simultaneous determination of non-steroidal anti-inflammatory drugs using high-performance liquid chromatography

An isocratic high-performance liquid chromatographic procedure is presented for the screening of plasma samples for the presence of sixteen non-steroidal anti-inflammatory drugs. Detection was achieved simultaneously at two wavelengths (254 and 370 nm) and the purity of the eluted peaks was tested using absorbance ratios at the two wavelengths; identification could thus be effective without interferences from substances of other pharmacological classes. The drugs were extracted simultaneously with diethyl ether after acidification and separated from each other on an octadecyl reversed-phase column using only one eluent, acetonitrile-0.3% acetic acid-tetrahydrofuran (36:63.1:0.9, v/v). The recovery, precision and reproducibility of the method were satisfactory as it allowed the determination of the drugs from infra- to supratherapeutic concentrations.

Role of ancillary properties of beta-adrenoceptor antagonists in protecting the heart from anoxia

The mechanism of the cardioprotective action of beta-blocking drugs against anoxia or ischemia is still not clear. We used beta-blockers (5 x 10(-7) M) of various pharmacodynamic profiles in a model of isolated, perfused working guinea pig heart subjected to 20 min of anoxia to study this. The cardioprotective effects were evaluated by measuring the recovery of the flow indices after 15 min of reoxygenation. There was a significant cardioprotective action (as measured by the effect on stroke volume recovery and on recovery of other flow and work indices) of the beta-blocking properties (nadolol, P less than 0.05), of the membrane-stabilizing property [+)-propranolol, P less than 0.05) and of a combination of these two properties with (+/-)-propranolol, which had a significantly greater effect than nadolol (P less than 0.05). The addition of weak (acebutolol) or strong (pindolol) intrinsic partial agonist activity had no clear unfavourable effect, as the degree of cardioprotection was comparable with that obtained with (+/-)-propranolol. The stroke volume recovery (percent recovery after anoxia) in the control hearts was 42.57 +/- 12.75 compared to 54.84 +/- 6.94 in hearts pretreated with nadolol, 62.99 +/- 11.41 with (+)-propranolol, 71.02 +/- 11.36 with (+/-)-propranolol, 72.63 +/- 13.08 with acebutolol and 68.01 +/- 15.42 with pindolol. In vitro heart protection from anoxia with beta-blockers would appear to be related to beta-blocking activity and/or membrane stabilizing property but not a function of partial agonist activity. These ancillary properties of beta-blockers should thus be taken into account in studies on cardioprotection.

Tianeptine and its main metabolite pharmacokinetics in chronic alcoholism and cirrhosis

The effect of chronic alcoholism (with or without associated moderate cirrhosis) on the disposition of the antidepressant tianeptine, which is devoid of substantial first-pass metabolism, was examined in 21 patients and 11 age-matched controls. Pharmacokinetic parameters for tianeptine and its C5 acid analogue metabolite (MC5 metabolite) were estimated by non-compartmental analysis. The area under the curve (AUC) for tianeptine, following a 12.5mg single oral dose, was decreased by 31% in chronic alcoholics and increased by only 14% in cirrhotics, compared to controls. These changes did not attain statistical significance. The trend of changes in the AUC for the MC5 metabolite was similar to that observed for the parent drug. No statistical difference was found in the terminal half-life for both tianeptine and its MC5 metabolite between patients and controls. On the basis of this study, it appears unnecessary to modify the proposed dosage regimen used in clinical trials (tianeptine sodium salt 12.5mg 3 times daily) in chronic alcoholics with or without associated moderate cirrhosis.

Clinical pharmacokinetics of nonsteroidal anti-inflammatory drugs in the cerebrospinal fluid

The pharmacokinetics of nonsteroidal anti-inflammatory drugs (NSAIDs) in the cerebrospinal fluid (CSF) is of clinical interest as it may be related to some of their properties and side-effects. Two types of NSAIDs can be described with respect to their concentration and time course in CSF: in the first type, the transfer across the blood-brain barrier seems to be controlled by simple physico-chemical factors. These drugs (oxyphenbutazone, indomethacin, ketoprofen) are characterized by a high lipophilicity. At steady state, their free plasma concentrations correspond to their CSF concentrations. The second group consists of more hydrophilic compounds (salicylates); there is no correlation between plasma concentrations and CSF concentration. Further investigation needs to be carried out on CNS side-effects and the antialgesic activity of salicylates in relation on their CSF distribution.

The effect of food on the systemic availability of ketoprofen

We have studied the pharmacokinetics of ketoprofen, a non-steroidal anti-inflammatory drug, in 12 patients after a single 100 mg oral dose both in fasting conditions and with a meal. Food significantly affected the peak plasma concentration of ketoprofen and decreased its absorption rate. However, the extent of absorption of ketoprofen, as reflected by the area under the plasma concentration time curve, appeared to be unchanged in the presence of food.

Total and free ketoprofen in serum and synovial fluid after intramuscular injection

Free and total ketoprofen levels in serum and synovial fluid were determined in 37 patients after a single intramuscular injection of ketoprofen, 100 mg. Free drug was separated by equilibrium dialysis. Ketoprofen was assayed by HPLC. Ketoprofen penetrated into the joints rapidly and significant concentrations were found at 15 minutes. The equilibrium time was about 3 1/2 hours. The AUC for total ketoprofen was greater in serum than in synovial fluid. On the other hand, the free fraction AUC in the serum and synovial fluid were quite similar. The mean residence time in the joint was about three times that in the systemic circulation. Ketoprofen was strongly bound to proteins and the percentage of free ketoprofen was not significantly different between serum and synovial fluid. These results provide a possible explanation for duration of the therapeutic effect of ketoprofen despite the short elimination half-life from the serum.

Conversion from intravenous to oral slow-release disopyramide in acute myocardial infarction

Twelve patients with acute myocardial infarction were given 1.5 mg/kg/5 min bolus +0.4 mg/kg/hr 6 hr IV infusion of disopyramide followed by 250 mg twice daily of a slow-release oral formulation of this drug. Plasma concentrations of total disopyramide rapidly reached steady-state within the therapeutic margins. The plasma steady-state concentrations of the major metabolite mono-N-dealkyl-disopyramide (MND) showed large intra-individual variations. There was no correlation between plasma levels of either disopyramide or MND and the occurrence of anticholinergic side effects. The drug had no significant effect on mean blood pressure, heart rate, or ECG intervals. This therapeutic regimen, including conversion from the IV form to oral slow-release tablets, could be recommended in myocardial infarction.

[Determination of protein binding of drugs using equilibrium dialysis. Influence of volume displacement caused by osmotic pressure]

By the determination of the free concentration of a drug using the equilibrium dialysis method, a volume shift could be observed, inducing a dilution of the protein medium. The value of this volume shift varies with the plasmatic sample and could produce a misdetermination of the free fraction which could be important, essentially for the drugs strongly bound to proteins.

[Clinical evaluation of drugs in chronic cardiac failure]

As the acute complications of cardiovascular diseases are better controlled, the number of patients with chronic heart failure will no doubt increase, together with the need for new treatments of this condition. The effectiveness of these new drugs on the heart function and on the patient's functional status, quality of life and survival must be assessed by very strict evaluation methods. Evaluating the cardiac function requires haemodynamic investigations by proven techniques. Even when taken globally, the haemodynamic values do not always provide information on the patient's clinical and functional status which must therefore be assessed separately, using specific methods. The exercise load, duration and oxygen peripheral consumption measured by established techniques are, in fact, the variables best correlated with the patient's functional status. The effects of drugs must be evaluated at rest and during exercise, but also in short and long term, with a systematic search for tachyphylaxis. Improvements in much less than quality of life much greater than and tolerance of treatment can be evaluated by appropriate questionnaires filled in by the patients. Assessing the effect of any treatment on survival of cardiac patients is always difficult. It requires epidemiological studies which are invariably delicate and costly but cannot be avoided for such an important matter.