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Trypsin

Trypsinum crystallisatum

For medical students2 min readUpdated 2026-10-10

Trypsin is a proteolytic enzyme of animal origin. In pharmacology, it is used locally as a mucolytic agent to liquefy sputum, though its endogenous role and participation in the pathogenesis of pancreatitis are equally vital for medical students to understand.

Pharmacological groupRespiratory system agents (enzymatic mucolytics)

FormulationPowder in ampoules or vials of 0.005 g and 0.01 g

Route of administrationInhalation (after reconstitution in 0.9% NaCl solution)

PathologyPremature enzyme activation causes pancreatic autodigestion (autolysis)

Pharmacological Group and Pulmonology Applications

Trypsinum crystallisatum (trypsin) is classified as an agent affecting the respiratory system. Specifically, it belongs to enzymatic mucolytic agents (a group of proteolytic enzymes that also includes chymotrypsin).

As a mucolytic, the drug acts on viscous respiratory secretions, facilitating their clearance. However, it is important to note that in modern clinical practice, enzymatic mucolytics (trypsin, ribonuclease, deoxyribonuclease) are used significantly less often, having been largely replaced by synthetic agents (acetylcysteine, carbocysteine, ambroxol, bromhexine).

Endogenous Trypsin and Enzyme Replacement Therapy

Beyond its use as a mucolytic, trypsin is a crucial endogenous enzyme. In complex monocomponent preparations of animal origin (e.g., pancreatin, derived from bovine pancreas, and its analogues like Mezim, Triferment), proteases play a key role in digestion.

Although pancreatin dosing is calculated based on lipase content (daily dose 5–10 g), the proteolytic enzymes within it are essential for enzyme replacement therapy in chronic pancreatitis, hepatopancreatic disorders, and gastritis with reduced acidity (anacid and hypoacid states). These medications are administered strictly before meals.

Role of Trypsin in the Pathogenesis of Pancreatitis

Special attention in pharmacology should be given to the role of trypsin in destructive processes. Normally, the pancreas secretes an inactive zymogen—trypsinogen.

In acute pancreatitis, exacerbations of chronic pancreatitis, trauma, pancreatic cancer, or edema of the duodenal wall (e.g., following alcohol intake), the outflow of pancreatic secretions is impaired. Under these conditions, the enzyme cytokinase is activated. It triggers a pathological cascade: trypsinogen is converted into active trypsin not in the intestinal lumen, but directly within the pancreatic tissue itself.

This phenomenon is called self-digestion or autolysis. Active trypsin destroys the organ's tissues and, upon entering the systemic circulation, causes severe toxemia.

Pharmacological Regulation: Inhibitors and Blockers

To combat autolysis and toxemia, medications that suppress trypsin activity are utilized:

Protease inhibitors (antienzymatic drugs): Pantripin (a polypeptide from bovine pancreas) and Aprotinin (Trasylol, Gordox). They specifically inactivate circulating blood trypsin and block free kinins (mediators of inflammation and pain). They are administered as an intravenous infusion (in 5% glucose or 0.9% NaCl) in high doses. Caution is required due to the high risk of allergic reactions to foreign proteins.
M-cholinergic antagonists (anticholinergics): Drugs in this group (such as atropine) reduce the secretion of trypsinogen by the pancreas, preventing its premature activation and protecting the organ tissue from autodigestion.

Formulation and Administration Guidelines

When trypsin is prescribed as a mucolytic agent, it is administered via inhalation.

Formulation: Powder in ampoules or vials of 0.005 g and 0.01 g.
Reconstitution guidelines: Prior to inhalation, 0.005 g or 0.01 g of powder must be dissolved in 2–3 ml of 0.9% sodium chloride (NaCl) solution.

Mnemonic

Trypsin in the bronchi clears up the phlegm, in the pancreas it destroys tissue again.

Frequently asked questions

What is the mechanism of trypsin's mucolytic action at the biochemical level?

The mucolytic action of trypsin involves the liquefaction of viscous secretions in inflammatory respiratory diseases via proteolysis. At the biochemical level, trypsin acts as an endopeptidase, cleaving primarily internal peptide bonds of proteins.

In which surgical pathologies is trypsin applied topically?

Trypsin is applied topically in the following surgical pathologies:

Purulent wounds — for wound debridement and digestion of necrotic cell debris.
Postoperative wounds — as part of intensive postoperative wound care to modulate local proteolytic processes and create optimal healing conditions.
Trophical ulcers — topically as a solution or powder.

The goal of proteolytic enzyme therapy is to clear the affected area of necrotic tissues, fibrin, and pus.

Which mucolytic group does trypsin belong to?

Enzymatic mucolytic agents (proteolytic enzymes). In modern practice, they are used less frequently than synthetic analogues.

What is the role of trypsin in the pathogenesis of acute pancreatitis?

When secretion outflow is obstructed, the enzyme cytokinase activates trypsinogen into trypsin directly within the pancreatic tissue, causing organ autolysis (self-digestion) and severe toxemia.

Which drugs inactivate trypsin in the bloodstream?

Protease inhibitors (antienzymatic drugs) such as Pantripin and Aprotinin. They bind circulating trypsin and halt the destructive process.

How is trypsin prepared for inhalation?

The contents of the ampoule (0.005 g or 0.01 g of powder) must be dissolved in 2–3 ml of 0.9% sodium chloride solution.

Go deeper

Synthetic mucolytics (acetylcysteine, ambroxol) and their advantages over enzymatic ones
Protease inhibitors (Aprotinin, Pantripin): mechanism of action and indications
Enzyme replacement therapy preparations (Pancreatin, Mezim)
Pathogenesis of acute pancreatitis and the role of cytokinase
Use of M-cholinergic antagonists (atropine) to reduce trypsinogen secretion