Pirenzepine
| Evidence Level: L2 | Predicted Indications: 2 |
Table of Contents
Pirenzepine: From Peptic Ulcer Disease to Gastroduodenitis
One-Sentence Summary
Pirenzepine has historically been used (marketed in continental Europe as “Gastrozepin”) for peptic ulcer and gastroduodenal disease, though it currently holds no UK marketing authorisation. The TxGNN model predicts it may be effective for Gastroduodenitis, with 0 clinical trials and 19 publications currently supporting this direction — largely historical pharmacology and small trials from the 1980s–90s rather than modern registered studies.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not formally recorded in this evidence pack (drug-level data gap); historical literature consistently describes use in peptic ulcer / gastroduodenal ulcer disease |
| Predicted New Indication | Gastroduodenitis |
| TxGNN Prediction Score | 99.92% |
| Evidence Level | L2 |
| UK Market Status | Not marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
A formal mechanism-of-action record is not available in this evidence pack (drug-level data gap, DG002). However, the model’s own repurposing rationale and the supporting literature converge on a consistent picture: pirenzepine is a selective M1 muscarinic receptor antagonist that reduces gastric acid and pepsin secretion, stimulates duodenal bicarbonate and gastric prostaglandin E2 release, and promotes mucosal healing — a pharmacological profile documented as early as the 1980s under the brand name Gastrozepin.
Notably, this “new” prediction largely reaffirms the drug’s own historical use rather than pointing to a genuinely novel indication. Multiple included publications explicitly describe pirenzepine’s use in “gastroduodenal ulcer” and “erosive gastroduodenitis” (e.g. PMID 6783555, PMID 15074203), suggesting the compound fell out of routine practice — likely superseded by PPIs and H2-antagonists — rather than having failed on efficacy grounds.
Mechanistically, the antisecretory plus mucosal-protective (cytoprotective) dual action is directly relevant to gastroduodenitis, where reducing acid/pepsin exposure while supporting bicarbonate and prostaglandin-mediated mucosal defence would be expected to aid healing of inflamed gastroduodenal mucosa.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 6221398 | 1982 | RCT (multicentre) | Scand J Gastroenterol Suppl | Multicentre trial demonstrating efficacy and safety of pirenzepine in peptic ulcer and non-ulcerous gastroduodenal disease |
| 2694330 | 1989 | RCT (double-blind, multicentre) | Scand J Gastroenterol Suppl | In 104 patients with non-ulcer dyspepsia, pirenzepine improved endoscopic/clinical findings, though mucosal inflammation and H. pylori colonisation were unchanged |
| 8165833 | 1994 | RCT (comparative therapy) | Z Gastroenterol | Retrospective comparison of high-dose omeprazole vs famotidine + pirenzepine + antacid for acute upper GI haemorrhage, including erosive gastroduodenitis |
| 3855517 | 1985 | Review | N Z Med J | Review of pirenzepine’s clinical role in gastroduodenal ulcer management |
| 3297938 | 1987 | Cohort/Observational | Gut | Endoscopic study linking acid-secreting mucosal area to erosive gastritis severity; demonstrated a healing effect of pirenzepine |
| 1783354 | 1991 | Cohort/Combination trial | Fukuoka Igaku Zasshi | Pirenzepine (M1 antagonist) combined with famotidine (H2 antagonist) significantly reduced tetragastrin-stimulated gastric acid secretion versus either agent alone |
| 3544186 | 1986 | Comparative physiology study | Scand J Gastroenterol | In duodenal ulcer patients, IV pirenzepine produced antisecretory/motor effects comparable to atropine on gastroduodenal manometry |
| 15074203 | 2003 | Review | Klin Khir | Reassessment of pirenzepine’s pharmacology, highlighting cytoprotective effects and utility in chronic pancreatitis and stress-ulcer prophylaxis |
| 2636820 | 1989 | Animal study | Arch Int Pharmacodyn Ther | In rats, pirenzepine reduced cysteamine-induced gastric/duodenal ulceration and improved mesenteric blood flow, outperforming atropine |
| 6783555 | 1981 | Mechanistic study | Int J Clin Pharmacol Ther Toxicol | Showed pirenzepine inhibits gastric mucosal carbonic anhydrase, proposing an additional mechanism to antimuscarinic acid suppression in gastroduodenal ulcer therapy |
UK Market Information
Pirenzepine currently holds no UK marketing authorisation (0 licences on record; market status: Not marketed). Historical formulations (marketed as Gastrozepin in continental Europe, e.g. Germany, Italy) are referenced throughout the literature but are not available in the UK market. No BNF entry currently exists for this drug.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Note: Formal safety data (warnings, contraindications, drug interactions) are recorded as an unresolved, blocking data gap (DG001) — MHRA/SmPC-level labelling information has not yet been sourced and must be obtained before any safety assessment can be completed.
Additional Predicted Indication (Lower Priority)
For reference, TxGNN also ranked Irritable Bowel Syndrome (score 99.54%, Evidence Level L3, Decision Stage S1) as a candidate. However, the only identified human RCT (PMID 2559903, double-blind crossover) reported a non-effect of pirenzepine in dietary-resistant IBS. Remaining evidence is limited to unrelated animal/mechanistic studies. Recommendation: Hold — this indication is not supported for further pursuit at this time.
Conclusion and Next Steps
Decision: Proceed with Guardrails (Gastroduodenitis indication only)
Rationale: Historical evidence (1980s–90s RCTs and mechanistic studies) consistently supports pirenzepine’s antisecretory and mucosal-protective effect in gastroduodenal disease, giving reasonable L2-level evidence. However, this is essentially a reaffirmation of a historical, now-lapsed use rather than a novel indication, and critical safety/regulatory data remain unresolved.
To proceed, the following is needed:
- Formal SmPC-level safety data — warnings, contraindications, DDI (blocking gap DG001)
- Formal DrugBank-sourced mechanism-of-action documentation (gap DG002)
- Clarification of why UK/EU marketing authorisation was never obtained or was withdrawn
- Assessment against current standard-of-care comparators (PPIs, H2-antagonists), since nearly all evidence pre-dates modern H. pylori era management
- No further action recommended on the irritable bowel syndrome candidate given negative RCT evidence
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.