The anti-anaphylactic action of tiaramide hydrochloride

Comparative effects of various calcium entry blockers and anti-asthmatic compounds on antigen-induced bronchoconstriction in rat and histamine release from rat mast cells

The effects of four calcium entry blockers (diltiazem, nifedipine, mesudipine and verapamil) were studied on antigen-induced bronchoconstriction in sensitized rats and histamine release from rat mast cells, in comparison with compounds frequently used in atopic patients (theophylline, isoproterenol, disodium cromoglycate, ketotifen and clemastine). The four Ca2+ entry blockers produced a dose-related inhibition of the IgE-dependent bronchoconstriction in rat whereas the other drugs exhibited a weak effect or even were inactive. 48/80-induced histamine release was antagonized by nifedipine, verapamil and ketotifen. On the contrary, diltiazem, mesudipine, theophylline, isoproterenol, disodium cromoglycate and clemastine were not able to interfere with this release process. These data may suggest an important role of both extra- and intracellular calcium in such phenomena.

Tiaramide--a new oral drug for the treatment of asthma

1 TIaramide, an anti-inflammatory drug, inhibits the action of mediators released from mast cells and has direct smooth muscle relaxant properties. It may therefore have a beneficial effect in asthma. 2 A double-blind crossover trial comparing the bronchodilator activity of tiaramide and placebo over 16 days was undertaken in 13 patients with asthma. 3 Peak expiratory flow rate (PEFR) was recorded on three separate occasions every day and frequency of salbutamol aerosol usage was noted on a diary card. 4 During treatment with tiaramide the mean mid-morning PEFR (362 1/min) was higher than mean PEFR on placebo (328) (P less than 0.001) as was the evening PEFR (378) compared with placebo (388) (P less than 0.001). 5 There was a significant reduction in daily use of the salbutamol inhaler whilst on tiaramide (1.8) compared with placebo (2.3) (P less than 0.05). 6. Tiaramide may be a useful addition to existing prophylactic treatment for asthma.

Urinary metabolite profile of tiaramide in man and in some animal species

1. The metabolism of tiaramide, 4-[(5-chloro-2-oxo-3(2H)-benzothiazolyl)acetyl]-1-piperazineethanol, was studied in healthy male volunteers and experimental animals. 2. Tiaramide was extensively metabolized in human with only 1.5% excreted unchanged. 3. Urinary metabolites were identified by FD, CI and EI mass spectral comparison with authentic standards. The major urinary metabolites in human were 4-[(5-chloro-2-oxo-3(2H)-benzothiazolyl)acetyl]-1-piperazineacetic acid (TRAA), 4-[(5-chloro-2-oxo-3(2H)-benzothiazolyl)acetyl]-1-piperazineacetic acid 1-oxide (TRAO) and the O-glucuronide of tiaramide. 4. TRAO, a new metabolite identified in human urine, was also present in mouse, rat, guinea-pig and monkey, but in smaller amounts than for human. 5. Sex differences in the excretion of sulphate of tiaramide were noted only in the rat.