Pharmakologie des Buscopan

Centrally acting anticholinergic drug trihexyphenidyl is highly effective in reducing nightmares associated with post-traumatic stress disorder

INTRODUCTION

Following a case study on scopolamine butyl bromide, an anticholinergic drug, we studied the effect of a central anticholinergic drug on post-traumatic stress disorder (PTSD)-related flashbacks and nightmares.

METHODS

We administered trihexyphenidyl (TP) to 34 patients with refractory PTSD-related nightmares and flashbacks (open-label trial [n = 22]; single-blind trial [n = 12]), who had previously received psychiatric treatment for approximately 2-15 years, without therapeutic benefits. The effect of TP was determined using the Clinician-Administered PTSD Scale (CAPS) and the Impact of Event Scale-Revised (IES-R).

RESULTS

Overall, most patients reported an improvement to none or mild on the CAPS for nightmares (88%) and flashbacks (79%).

CONCLUSION

This study is the first to demonstrate the potential efficacy of TP in the treatment of refractory PTSD-related nightmares and flashbacks. Further double-blind, randomized control trials are needed to explore the potential clinical benefits of TP in PTSD.

Dose-response relationships of intravenous hyoscine butylbromide and atropine sulphate on heart rate in healthy volunteers

Heart-rate responses to intravenous hyoscine butylbromide, atropine and physiological saline in cumulative dosage regimens have been recorded in six healthy subjects. Atropine sulphate induced bradycardia at low, and tachycardia at higher, dose levels whereas hyoscine butylbromide caused only tachycardia but with a flatter dose-response relationship. Exact potency ratios could not be calculated because of the differing dose-response curves. However, an approximate estimate from a comparison of equiactive doses at the upper part of the curve yielded a value less than one half that obtained from the drugs' affinity constants in guinea-pig ileum. The findings suggest that, in addition to its action as a muscarinic antagonist, hyoscine butylbromide is a ganglion blocker in man as it is in animals.

The actions of atropine, tropenziline and N-butyl hyoscine bromide on the isolated distal colon of the guinea-pig: a comparison of their activities and mechanisms of action

In the guinea-pig isolated distal colon, the order of anticholinergic activity is as follows: atropine > tropenziline bromide > N-butyl hyoscine bromide. The reduction in the responses to pelvic and transmural stimulation produced by tropenziline and N-butyl hyoscine bromide is due partly to their ganglion blocking activity. This effect also explains the reduction they cause in acetylcholine output on pelvic nerve and transmural stimulation. Since atropine also reduces acetylcholine release on pelvic nerve stimulation, it is suggested that muscarinic receptors of the parasympathetic ganglia are involved in transmission of pelvic nerve impulses.

Anticholinergic effects and passage through the intestinal wall of N-butylhyoscine bromide

The effects of N-butylhyoscine bromide (Buscopan) were examined on responses of guinea-pig isolated intestine to transmural stimulation and to peristalsis induced by raising the intraluminal pressure. The drug acted rapidly and in low concentration to abolish peristaltic activity and responses to transmural stimulation when applied to the serosal surface of the ileum, but from 100 to 1000 times the concentration was required when it was applied to the mucosal surface. The effects were more persistent after mucosal than after serosal application. N-Butylhyoscine bromide was bound to mucus and mucosal material, the ratio of free to bound drug being 2:1. The drug passed through portions of the intestinal wall containing Peyer’s patches more rapidly than through portions containing no macroscopically visible lymphoid tissue. The rate of passage through Peyer’s patches, but not through other portions, increased with increasing hydrostatic pressure. These findings help to explain why enterally administered N-butylhyoscine bromide exerts anti-cholinergic effects on the gut without producing systemic actions.

Observations on the efficacy of oral hyoscine N-butyl bromide

Hyoscine N-butyl bromide (Buscopan) antagonized the spasmogenic action of acetylcholine on guinea-pig isolated ileum, having a pA2 of 7·8. The drug also had intestinal antispasmodic activity in the anaesthetized cat after either parenteral or enteral administration. With the enterally administered drug larger doses were required, but the effects were longer lasting. Enterally administered in conscious dogs the drug sometimes produced a small increase in heart rate.