Comparison of Phenyl– and Monophenylbutazone (Mobutazon®), Especially in Respect to the Incidence of Side Effects: A Double-Blind Study

Summary and Conclusion

The double-blind technique was employed in a clinical trial, carried out on 114 patients suffering from rheumatic diseases, in order to compare phenylbutazone with Mobutazon® (monophenylbutazone), especially in respect to the incidence of side effects. The treatment was continued for six weeks.

In both groups a good effect was recorded in about 75 per cent of the cases.

Side effects appeared with fairly equal frequency (about 50 per cent) in both groups, but differed significantly in severity.

Important or subjectively unpleasant side effects, probably due to the “butazone“ treatment, were seen in 15 (25 per cent) of the patients treated with phenylbutazone and in 5 (9 per cent) of the Mobutazon patients.

Differences between the two groups were found also in the laboratory rests. Moreover, in the phenylbutazone group there was, during the first two weeks, a weight gain which closely agrees with the findings of other investigators.

The weight gain is presumably caused by retention of water which again is a consequence of an increased re-absorption of Na+, Cl—, and water in the renal tubules (Brodie, Lowman, Burns, Lee, Chenkin, Goldman, Weiner & Steel 1954, Fjellström, Goldberg, Lindgren & Nilsson 1957, Goodman & Gilman 1965 and Strandberg 1965).

On an average, no weight gain appeared in the Mobutazon group, a sign that little or no water retention occurred.

The patients on phenylbutazone showed, throughout the trial, a slight decrease in hemoglobin concentration; those on Mobutazon showed a slight increase.

The tendency to a decrease in the erythrocyte sedimentation rate during the period of the trial was more definite in the Mobutazon group.

Two patients of the Mobutazon group and seven of the phenylbutazone group showed serum iron levels below 0.30 mg/l. during the test.

One patient of the Mobutazon group and three of the phenylbutazone group, who did not initially have albuminuria, developed this sign during the experiment.

Patients whose urine showed no or only a few erythrocytes per microscopic field before the trial but who had a maximal score in the course of the trial:

In the Mobutazon group: 1; no patient excluded.

In the phenylbutazone group: 6; one patient left out of the trial because of microscopic hematuria.

The therapeutic efficacy of Mobutazon in this trial was equal to that of phenylbutazone in the doses used, whereas the incidence of important side effects was significantly lower.

Résumé

La technique de la substitution réciproque de préparations à l'insu des malades répartis en deux groupes a été utilisée dans une épreuve clinique à laquelle furent soumis 114 malades atteints de polyarthrite chronique évolutive, aux fins de comparer le phénylbutazone avec le Mobutazone® (monophénylbutazone) spécialement en ce qui concerne la production d'effets accessoires. Le traitement a été poursuivi durant six semaines.

Dans les deux groupes on a noté un effet favorable dans environ 75 % des cas.

Les effets accessoires se manifestèrent dans les deux groupes avec une fréquence égale (environ 50 %), mais présentèrent des degrés très variés de gravité. L'efficacité du Mobutazone dans cette épreuve correspondait à celle du phénylbutazone aux doses utilisées, mais la manifestation d'effets accessoires sérieux était remarquablement moins fréquente.

Zusammenfassung

Die Technik des gegenseitigen Austausches von Präparaten ohne Wissen der in zwei Gruppen eingeteilten Patienten kam bei einem klinischen Versuch zur Anwendung, der an 114 an rheumatischen Krankheiten leidenden Patienten vorgenommen wurde. Der Zweck lag in einem Vergleich von Phenylbutazon mit Mobutazon® (Monophenylbutazon), vor allem in Hinblick auf das Auftreten von Nebenwirkungen. Die Behandlung wurde sechs Wochen lang fortgesetzt.

Bei beiden Gruppen wurde in 75 % der Fälle eine gute Wirkung vermerkt.

Nebenwirkungen traten in beiden Gruppen mit annähernd gleicher Häufigkeit auf (50 %), wichen jedoch in ihrer Schwere beträchtlich voneinander ab.

Die therapeutische Wirksamkeit von Mobutazon war in diesem Versuch bei den verwendeten Dosen der von Phenylbutazon gleich, hingegen traten Nebenwirkungen von Bedeutung in erheblich geringerer Zahl auf.