LACTOLOGY FOUNDATION

Multienzymes and Acid Preparations

ATC code: A09AC02
ATC designation: Multienzymes and acid preparations
Pharmacological/therapeutic group: Digestives, including enzymes; enzyme and acid preparations, combinations

1. ATC Classification and Pharmacological Profile

A09AC02 is classified in the WHO Anatomical Therapeutic Chemical (ATC) system under A — Alimentary tract and metabolism; A09 — Digestives, including enzymes; A09A — Digestives, including enzymes; A09AC — Enzyme and acid preparations, combinations. Its official designation is “multienzymes and acid preparations.” The current WHO ATC/DDD Index does not assign a Defined Daily Dose (DDD) to A09AC02.

A09AC02 is a heterogeneous class rather than a single pharmacologically uniform medicine. Products may combine several digestive enzymes with an acidifying constituent and, in some formulations, additional digestive components. Regulatory examples illustrate this variability. Documented formulations have contained combinations of amylase, proteases, lipase, pancreatin, pepsin, papain, bromelain, cellulase or lactase, together with betaine hydrochloride; some preparations have additionally contained ox bile extract. The composition and quantitative enzyme activity therefore vary substantially between products.

The principal pharmacological objective is to facilitate intraluminal digestion. Proteolytic enzymes hydrolyse dietary proteins, amylolytic enzymes facilitate carbohydrate digestion, and lipolytic enzymes contribute to hydrolysis of dietary triglycerides. Other enzymes may target specific substrates, depending on the formulation. Acidifying constituents are intended to lower gastric pH and may thereby promote an environment favourable for acid-dependent digestive processes and the activity of certain enzymes.

For betaine-hydrochloride-containing preparations, controlled human pharmacodynamic studies demonstrate substantial but temporary gastric acidification. In healthy volunteers with proton-pump-inhibitor-induced hypochlorhydria, 1,500 mg betaine hydrochloride reduced mean gastric pH from approximately 5.2 to 0.6, with a mean time to pH below 3 of about 6 minutes and persistence below pH 3 for approximately 73 minutes. The magnitude and duration of acidification are influenced by food and dose.

These findings demonstrate pharmacological gastric re-acidification but should not be extrapolated to every A09AC02 product because the amount and nature of the acidifying constituent differ between formulations.

Pharmacokinetic considerations

Conventional systemic pharmacokinetic parameters have limited relevance to many of the enzyme constituents of this class.

Digestive enzymes are predominantly large protein molecules intended to act within the gastrointestinal lumen. Pancreatic enzyme preparations, for example, are not appreciably absorbed intact from the maternal gastrointestinal tract. Their pharmacological activity is therefore principally local rather than dependent on measurable systemic plasma concentrations. LactMed specifically notes this lack of appreciable gastrointestinal absorption for pancrelipase.

Consequently, conventional parameters such as plasma protein binding, volume of distribution, systemic elimination half-life and renal clearance are generally inappropriate descriptors of the clinically relevant disposition of the intact enzyme components.

The acidifying component requires separate consideration. Betaine hydrochloride dissociates in gastric fluid to betaine, protons and chloride. Its immediate acidifying effect is therefore local, whereas betaine can subsequently enter normal systemic metabolic pathways.

A09AC02 should consequently be regarded as a class combining two pharmacokinetically distinct principles:

• predominantly luminal digestive enzyme activity with little expected systemic exposure to intact enzymes; and
• local gastric acidification accompanied, for some acidifying compounds, by systemic handling of their non-acid moieties.

This distinction is particularly important when evaluating exposure during breastfeeding.

2. Toxicological Profile

The toxicology of A09AC02 is determined primarily by formulation, dose and route of exposure rather than by a single class-wide toxicological mechanism.

Gastrointestinal toxicity

At therapeutic oral doses, adverse effects are expected principally to involve the gastrointestinal tract. Depending on composition and dose, these may include abdominal discomfort, nausea, altered bowel function or irritation.

Acidifying constituents can substantially reduce intragastric pH. Betaine hydrochloride has produced marked transient gastric re-acidification in controlled human studies, including at doses between 1.5 and 4.5 g. Excessive acidification may therefore aggravate acid-related symptoms or pre-existing upper gastrointestinal mucosal disease.

This pharmacological effect should not, however, be equated with corrosive poisoning from concentrated mineral acids. Toxicological observations involving concentrated industrial acids cannot appropriately be extrapolated to correctly formulated medicinal preparations.

Enzyme-related toxicity and hypersensitivity

Digestive enzymes generally have low potential for systemic toxicity after conventional oral administration because systemic absorption of intact active enzyme is limited. Nevertheless, enzyme proteins may possess allergenic and sensitizing properties.

This issue is particularly relevant after occupational exposure to enzyme dusts and aerosols, where respiratory sensitization is well established for several enzyme proteins. Such observations demonstrate biological allergenicity but do not establish an equivalent risk during ordinary oral therapeutic administration.

Plant-derived proteolytic enzymes require additional formulation-specific consideration. Papain and bromelain, for example, have pharmacological and allergenic properties that cannot automatically be inferred from the behaviour of pancreatic enzymes. For bromelain, authoritative complementary-medicine guidance notes that information on safety during breastfeeding remains limited.

Thus, the reassuring pharmacokinetics of one enzyme constituent should not be generalized uncritically to every enzyme used in a multienzyme formulation.

High-dose and prolonged exposure

Toxicity associated with pancreatic enzyme replacement at very high cumulative doses is described for individual pancreatic enzyme preparations, but such findings should not automatically be extrapolated to all A09AC02 products, whose pancreatic-enzyme content may be much smaller or absent.

Similarly, potential adverse effects of papain, bromelain, bile constituents or other formulation-specific components belong primarily to the toxicological assessment of those individual substances.

No single characteristic acute poisoning syndrome can therefore be defined for A09AC02 as a class.

In overdose, the expected clinical manifestations depend on the precise formulation and may include gastrointestinal irritation, nausea, vomiting, abdominal pain or other component-specific effects. There is no class-specific antidote; management of significant poisoning is principally supportive and should be guided by the ingredients and clinical manifestations.

The available evidence does not identify a common clinically important genotoxic, mutagenic or carcinogenic hazard attributable to therapeutic use of the class as such. However, this should not be interpreted as evidence that every possible multienzyme/acid formulation has undergone comprehensive long-term toxicological evaluation.

3. Lactation Pharmacology and Breast-Milk Exposure

Direct evidence

No adequate published human lactation studies specifically characterizing A09AC02 multienzyme-and-acid combination products were identified.

There are no sufficiently characterized class-specific data establishing:

• serial concentrations of complete A09AC02 preparations or their active enzyme components in human milk;
• milk-to-plasma ratios;
• milk elimination kinetics;
• a class-specific Relative Infant Dose (RID); or
• plasma concentrations in breastfed infants.

Accordingly:

Milk-to-plasma ratio: not established.
Relative infant dose (RID): not established.
Infant plasma exposure: not established.

An RID should not be estimated theoretically when adequate maternal plasma and human-milk concentration data are unavailable.

Digestive enzyme components

The expected milk exposure to many digestive enzyme components is low on pharmacokinetic grounds.

Pancreatic enzymes provide the clearest relevant evidence. LactMed reports that pancreatic enzymes are not appreciably absorbed from the maternal gastrointestinal tract and therefore should not reach the breastfed infant through maternal systemic circulation and milk to a clinically relevant degree. Expert opinion cited by LactMed considers pancrelipase acceptable during breastfeeding. Direct maternal milk and infant serum concentration data nevertheless remain unavailable.

This constitutes indirect but clinically relevant evidence for A09AC02 products containing pancreatin or related pancreatic enzymes. It is not direct evidence for the complete multienzyme combination.

The same general physiological principle supports low expected milk transfer for other large protein digestive enzymes whose activity remains predominantly intraluminal: significant passage into milk requires prior maternal systemic absorption of intact or biologically active protein.

Furthermore, any enzyme protein reaching the infant orally through milk would encounter the infant gastrointestinal tract, where digestion and proteolysis would tend to reduce systemic exposure.

Consequently, clinically significant systemic infant exposure to intact digestive enzymes is mechanistically unlikely for poorly absorbed enzyme constituents.

However, A09AC02 is heterogeneous. This conclusion should not be extended automatically to every plant-derived enzyme or low-molecular-weight accompanying substance without consideration of its individual pharmacology.

An unusual observation involving pancreatic enzymes

A small body of clinical literature provides an interesting example of maternal pancreatic-enzyme administration affecting breast-milk composition indirectly.

LactMed reports maternal use of pancrelipase in cases involving breastfed infants with apparent reactions to dietary proteins. Maternal pancreatic enzyme supplementation has been associated in limited reports with reduced excretion of dietary ovalbumin into breast milk and apparent improvement in symptoms attributed to egg or cow's-milk protein exposure.

These observations do not demonstrate transfer of pancreatic enzymes into milk. If anything, the proposed mechanism is modification of maternal gastrointestinal digestion and absorption before dietary proteins reach the maternal circulation and mammary gland.

The evidence is limited and does not establish pancreatic enzymes as a standard treatment for food-protein reactions in breastfed infants, but it reinforces the distinction between an enzyme's maternal gastrointestinal action and direct infant exposure through milk.

Acidifying components

The acidifying component must be evaluated independently of the enzyme fraction.

Betaine hydrochloride dissociates in gastric fluid, and its pharmacodynamic effect—gastric re-acidification—cannot itself be transmitted to breast milk. The resulting betaine, however, is systemically available and participates in normal human metabolism.

Therefore, some contribution of absorbed betaine to maternal systemic pools and potentially to milk is biologically plausible. This does not establish a clinically significant incremental infant dose from therapeutic betaine hydrochloride.

Direct pharmacokinetic studies linking maternal A09AC02 dosing to milk betaine concentrations and infant exposure are lacking.

Overall expected exposure

For many A09AC02 preparations, the enzyme fraction is expected to contribute little or no clinically meaningful systemic infant exposure, particularly where the enzymes are large proteins acting locally in the maternal gastrointestinal tract.

The non-enzyme components create greater uncertainty because their absorption and metabolism vary. Consequently, the complete formulation—not simply the ATC code—must determine the final lactation assessment.

4. Effects in the Breastfed Infant and on Lactation

Effects in breastfed infants

No adequate prospective cohorts or controlled studies specifically evaluating infants breastfed during maternal treatment with A09AC02 combination preparations were identified.

For pancreatic enzymes, LactMed reports no relevant published information on drug levels in maternal milk or infant blood and no published evidence defining adverse effects in breastfed infants. Nevertheless, because maternal gastrointestinal absorption is negligible, clinically significant exposure is considered unlikely.

This distinction is important:

absence of documented adverse effects is not equivalent to demonstrated clinical safety.

For A09AC02, the evidence supporting low infant risk is predominantly pharmacokinetic and mechanistic rather than derived from systematic infant follow-up.

Potential adverse effects also depend on formulation. A preparation containing pancreatic enzymes and an acidifying salt cannot automatically be considered equivalent to one containing plant proteases, bile extracts or additional active constituents.

Particular caution is reasonable in premature neonates and medically fragile infants, not because a specific toxicity has been demonstrated, but because the consequences of unrecognized exposure or gastrointestinal intolerance may be greater in these populations.

Effects on lactation

No adequate evidence indicates that A09AC02 preparations as a class suppress prolactin secretion, interfere with oxytocin-mediated milk ejection, delay lactogenesis or reduce established milk production.

Pancrelipase has no documented adverse effect on lactation or breast-milk production in LactMed.

Papaya-derived products have historically been used as galactogogues in some populations, but LactMed states that scientifically valid clinical trials do not support papaya fruit or leaves as effective galactogogues. Such ethnomedical use should therefore not be interpreted as evidence that papain-containing A09AC02 preparations increase milk production.

A direct class-wide effect on lactation is pharmacologically unlikely because the intended therapeutic action is gastrointestinal.

Indirect reduction in milk production could theoretically occur if maternal treatment produced substantial gastrointestinal intolerance, reduced food intake, dehydration or systemic illness. Such an effect would reflect maternal toxicity rather than direct inhibition of lactation physiology.

5. Lactological Safety Assessment and Clinical Recommendations

The lactological assessment of A09AC02 is characterized by an important contrast: direct clinical lactation evidence is sparse, whereas the pharmacological characteristics of many digestive enzyme components predict very low infant exposure.

Breastfeeding compatibility

For a conventional A09AC02 preparation consisting predominantly of poorly absorbed digestive enzymes plus an acidifying component, available evidence does not provide a pharmacological basis for routine interruption of breastfeeding.

For pancreatic enzyme components in particular, negligible maternal gastrointestinal absorption provides substantial mechanistic reassurance, and LactMed considers pancrelipase acceptable during breastfeeding.

Nevertheless, the class is too heterogeneous for an unconditional class-wide declaration of safety.

The most appropriate interpretation is therefore:

Therapeutic use of a conventional multienzyme-and-acid digestive preparation is generally expected to be compatible with continued breastfeeding when the complete formulation contains no additional component with a specific lactation contraindication. This assessment is based mainly on pharmacokinetic and mechanistic reasoning rather than direct studies of A09AC02 combinations.

The exact composition should be checked whenever possible.

This requirement is particularly important for products containing multiple plant-derived enzymes, bile constituents, unusual acidifying agents or other active ingredients not inherent to the core multienzyme/acid concept.

Infant monitoring

Routine laboratory monitoring of a healthy term infant is not justified solely because the mother is receiving a conventional A09AC02 preparation.

Ordinary clinical observation is generally sufficient. If symptoms arise, clinically relevant findings could include:

• feeding intolerance;
• vomiting or diarrhea;
• unusual gastrointestinal symptoms;
• cutaneous or other manifestations suggestive of hypersensitivity.

Such effects are theoretical or formulation-dependent rather than established class-specific adverse reactions.

More individualized assessment is appropriate for premature infants, neonates with significant gastrointestinal disease, medically fragile infants, or situations involving unusually high maternal doses or complex combination products.

Dose–feed timing

There is no established evidence that separating administration of A09AC02 preparations from breastfeeding meaningfully reduces infant exposure.

For poorly absorbed digestive enzymes, dose–feed timing has little pharmacological rationale because maternal systemic concentrations are expected to be negligible.

For absorbable non-enzyme constituents, adequate human-milk concentration–time profiles are unavailable. An evidence-based optimal breastfeeding interval therefore cannot be defined.

Routine dose–feed scheduling is consequently not recommended.

Pumping and discarding milk

Routine pumping and discarding of breast milk is not pharmacologically justified during conventional therapeutic use of a simple A09AC02 preparation.

Temporary interruption should be considered only when another component of the formulation, maternal poisoning, severe adverse effects or another independent clinical circumstance provides a specific reason.

Overall lactological assessment

6. Conclusion

A09AC02 comprises multienzymes and acid preparations, a heterogeneous group of digestive combinations classified by WHO under enzyme and acid preparations. No WHO DDD is currently assigned to the class, consistent with the substantial variability in enzyme composition, activity and formulation.

The preparations act principally within the maternal gastrointestinal tract. Their enzyme components facilitate digestion of proteins, carbohydrates, fats or other dietary substrates, while acidifying constituents modify gastric pH. Individual products may contain markedly different combinations of pancreatic, microbial or plant-derived enzymes and acidifying compounds.

Direct lactation evidence for complete A09AC02 preparations is poor. Milk-to-plasma ratios, class-specific relative infant doses and infant plasma concentrations have not been established and should not be estimated without appropriate data.

For poorly absorbed digestive enzymes, particularly pancreatic enzymes, clinically meaningful transfer into human milk is mechanistically unlikely. LactMed reports that pancreatic enzymes are not appreciably absorbed from the maternal gastrointestinal tract and considers pancrelipase acceptable during breastfeeding, although direct milk-level and infant-level studies remain unavailable.

Acidifying and other non-enzyme constituents require separate assessment because their systemic disposition differs from that of large enzyme proteins. Betaine hydrochloride, for example, produces marked but transient gastric acidification and dissociates to betaine, protons and chloride. The local gastric pharmacodynamic effect should not be confused with systemic infant exposure.

The principal toxicological concerns of the class are formulation-dependent gastrointestinal intolerance, excessive acidification and hypersensitivity to enzyme proteins rather than systemic toxicity from the digestive enzymes themselves. The heterogeneous composition of A09AC02 prevents the safety profile of one enzyme or one product from being generalized automatically to all preparations.

Overall, conventional therapeutic A09AC02 multienzyme-and-acid preparations are expected to result in low exposure of the breastfed infant to active digestive enzymes, and breastfeeding can generally continue without interruption when the complete formulation contains no independently problematic constituent. The evidence supporting this assessment is predominantly pharmacokinetic and mechanistic rather than derived from direct clinical lactation studies.

Greater caution and individualized assessment are appropriate for complex formulations, unusually high maternal exposure, premature or medically fragile infants, and products containing additional active ingredients whose lactation safety has not been established.