Evaluation of the Efficacy of H₁ Blockers by Noninvasive Measurement Techniques

Abstract

Background: Evaluation techniques for determining the strength of action and the onset of activity of H₁ receptor blockers have not yet been sufficiently standardized. Objective: The clinical efficacy of the H₁ receptor blocker loratadine was to be measured upon a wheal response subsequent to an intracutaneous injection of 0.1 ml histamine (0.1%). Methods: In a pilot study, 10 patients were treated with the H₁ receptor blocker loratadine for a period of 7 days. Various noninvasive measurement techniques, i.e. 20-MHz sonography, laser-Doppler flowmetry, chromatometry using the Lab* system and computer-assisted planimetry, were applied to provide a quantitative evaluation of the wheal and the marginal erythema. Using these quantification methods, the development of the urticarial reaction 20 min after injection and its decline were evaluated. Results: The urticarial reaction was reduced substantially under treatment with 10 mg loratadine over a period of 7 days. The methods we used could accurately quantify different aspects of the urticarial reaction noninvasively. Conclusions: All of the chosen measurement techniques are widely recognized. For objective assessment of the urticarial reaction with high-frequency ultrasound, we recommend the measurement of the distance between skin entrance echo and fascia since the demarcation of the wheal is often impossible by ultrasound. In order to improve comparison of results of various workgroups in the future, we therefore suggest the use of the selected combination of noninvasive procedures as a standard for evaluating the efficacy of H₁ receptor blockers.

High-Frequency Ultrasound in the Evaluation of Pharmacological Effects on the Skin

“…Along with other trials on experimental inflammatory dermatoses [18,22], this latter study [23] indicates that sonography images dermal edema as an echo-poor zone within the dermis. Gniadecka and Quistorff [24] produced evidence that echogenicity is a valid parameter for changes in dermal water content.…”

“…Furthermore, 20-MHz B-scan ultrasound permits the quantitative evaluation of the efficacy of H1 receptor blockers by measuring the wheal response to an intracutaneous injection of 0.1 ml histamine (0.1%) [23]. Hoffmann et al [23] reported that the urticarial reaction, which could be detected sonographically prior to its clinical appearance, was significantly reduced in patients who had been treated with 10 mg loratadine over a period of 7 days.…”

“…Hoffmann et al [23] reported that the urticarial reaction, which could be detected sonographically prior to its clinical appearance, was significantly reduced in patients who had been treated with 10 mg loratadine over a period of 7 days. As an indirect but very reliable parameter for the thickening of the corium caused by the wheal, the distance between skin entry echo and muscle fascia was chosen, since the axial diameter of the indistinctly limited echo-poor area corresponding to histamineinduced edema is difficult to determine [23]. This paper demonstrates that high-frequency ultrasound improves the comparability of the results obtained by different working groups in issues of drug efficacy, which marks a major progress in pharmacological research.…”

The Effect of the Base on the Kinetics of Action of the Capsaicinoid Nonivamide: Evaluation with a Hyperemic Test

“…Using a videocamera, the outlined areas are then scanned into an analysis programme integrated in a PC with video interface. The area, circumference and diameter were determined automatically by means of an analysis programme (Micro Scale, Digithurst, UK) [19].…”

“…In Germany, the combination of nonivamide and nicoboxil (Finalgon ® ) has been used for the treatment of rheumatic muscular, arthritic and neuralgic pain and of traumatic injuries for decades [15]. The hyperemic reaction can be determined quantitatively both directly by laser Doppler perfusion imaging [16][17][18] and indirectly by planimetry [19].…”