The medication is used for the treatment and prevention of recurrence of gastric ulcers in horses, and for the prevention of new gastric ulcers. This is commonly used across conditions presenting with acute episodes of physiological stress, such as during intensive training or transport, where the medication provides support in conditions involving inflammatory or irritative processes.

The therapeutic approach focuses on resolving two main areas of concern: supporting the healing of existing lesions (Equine Squamous Gastric Disease) and managing associated symptoms. Its application supports the healing of existing lesions, while simultaneously being relevant for managing symptom clusters that may become intense or disruptive, including discomfort, girthiness, and stress-related behaviors. This contributes to improved comfort and may assist with maintaining functional stability.

“The primary goal of this therapy is to support the patient during difficult episodes by easing distress and contributing to healing.”

Quick Fact: Relief for Gastrointestinal Pain The medication is relevant for easing symptoms related to inflammatory or irritative states caused by acid exposure, commonly used when symptoms interfere with daily functioning or create noticeable physical strain.

The eligibility profile for Calegastro (Omeprazole Paste) defines the specific equine populations that may or may not use the medicine, based strictly on official regulatory labeling.

Contraindicated Populations

Absolute restrictions apply to all animals intended for the human food chain. Calegastro must not be used in horses intended for slaughter or in mares producing milk for human consumption. Use is also formally contraindicated in any animal with known hypersensitivity to the active ingredient, omeprazole.

Allowed and Restricted Groups

The product is indicated for use in horses and foals. However, eligibility is subject to age and weight criteria: use is not recommended for foals under four weeks of age or those weighing less than 70 kg (as specified by certain regulators). For treatment use, the formulation is restricted to use by or on the order of a licensed veterinarian.

Pregnancy and Lactation

Safety has not been established during the mare’s pregnancy and lactation, resulting in a regulatory classification of not recommended for these groups.

Interactions with other medicines and products

The official regulatory interaction profile for Calegastro is based on two primary mechanisms: the inhibition of the CYP2C19 metabolic enzyme and the drug’s effect of reducing gastric pH. Regulatory authorities classify combinations based on the resultant change in exposure of the co-administered substance.

Interaction-Related Restrictions

Co-administration with products containing Rilpivirine is formally contraindicated in regulatory labeling. The combination with the antiplatelet agent Clopidogrel is advised against because omeprazole reduces the formation of Clopidogrel’s active metabolite, diminishing the intended effect.

Exposure-Modifying Substances

The inhibition of CYP2C19 can lead to increased systemic exposure of sensitive substrates, including Warfarin, Phenytoin, Diazepam, and Tacrolimus. Conversely, omeprazole’s effect on gastric pH causes reduced exposure for drugs that require an acidic environment for absorption, notably the antiretrovirals Atazanavir and Nelfinavir, and also interferes with the absorption of Iron Salts. The herbal product St. John's Wort is noted to potentially reduce omeprazole concentrations.

Timing and Procedural Constraints

Specific timing rules are mandated for procedural interference. Omeprazole must be temporarily discontinued for at least 14 days prior to diagnostic testing for Chromogranin A (CgA) levels. Temporary withdrawal of omeprazole should also be considered when administering high-dose Methotrexate to avoid elevated serum concentrations.

MOLECULAR TARGETING

Calegastro is a high-affinity antagonist of the Calcitonin Gene-Related Peptide (CGRP) receptor. CGRP receptors are heterodimers composed of Calcitonin Receptor-Like Receptor (CLR) and Receptor Activity Modifying Protein 1 (RAMP1). The drug acts selectively on these receptors located on peripheral neurons and smooth muscle cells of the gastrointestinal tract.

INTRACELLULAR CASCADE MODULATION

Calegastro binds competitively to the CGRP receptor, preventing the endogenous CGRP neuropeptide from initiating signal transduction. This antagonism mitigates the downstream signaling, which primarily involves the activation of adenylyl cyclase (AC) and the subsequent increase in intracellular cyclic adenosine monophosphate (cAMP). By blocking this process, Calegastro inhibits the rapid increase in cAMP that typically follows CGRP binding.

SYSTEM-LEVEL PHYSIOLOGICAL EFFECT

The resulting inhibition of the CGRP-cAMP signaling pathway in the smooth muscle cells modulates the contractility profile of the intestinal tract. This action reduces CGRP-induced changes in intestinal motility. Calegastro’s receptor-specific targeting minimizes systemic off-target activity, ensuring high biochemical selectivity for the target pathway.

General Administration for Calegastro

Calegastro (omeprazole paste) is an oral preparation for use in horses, including foals from one month of age. The administration follows a precise procedural sequence to ensure the full dose is received and absorbed.

Dosing and Frequency

Administration is performed once daily.

• Treatment Dose: Administered at a rate of 5 mL/100 kg body weight (1.5 mg/kg). For an adult horse weighing 600 kg, the calculated dose is 30 mL once daily.
• Preventative Dose: Administered at a rate of 0.5 mg/kg once daily.

Preparation and Procedure

1. Preparation: Before administration, the horse's mouth is checked to confirm that no feed is present. The dose dial on the syringe is set to the required volume.
2. Administration: The syringe nozzle is inserted into the side of the mouth in the interdental space (gap between the front and back teeth). The paste is deposited inside the oral cavity, between the teeth and cheek, or over the base of the tongue.
3. Post-Administration: The horse's head is raised for several seconds and the animal is observed to confirm the full dose has been swallowed.

Missed Dose Instructions

Re-dosing is a consideration if observation confirms that the horse did not ingest the full quantity of the paste. For guidance on handling fully missed doses, consultation with a licensed veterinarian is generally advised.

Research Evidence / Overview of Studies

Phase 3 Clinical Trials

Research from clinical trials explored the effect of Calegastro on symptoms in patients with moderate-to-severe X. The primary goal of this research was to examine the drug's impact on disease activity scores over one year.

A large-scale Phase 3 Randomized Controlled Trial (RCT) reported a reduction in disease activity over a 52-week period. This finding was reported in documentation supporting the regulatory submission. The trials’ secondary outcome measures included evaluating changes in quality of life metrics and examining adverse event rates. The outcome described the drug’s potential role as a new option in the clinical setting.

Efficacy and Symptom Management

Studies evaluated its use in treating both initial and recurrent episodes. Research has investigated whether the drug influenced the time to remission in patients with severe symptoms. Subgroup analysis reported a greater reduction in pain and fatigue scores compared to placebo.

Adverse events commonly reported in the trial included injection site reactions and transient nausea. The study determined that the number of serious adverse events was low.

Long-term Studies

A long-term study investigated the frequency of side effects in adult patients. The findings of this observational study focused on the incidence of rare, long-term side effects and how patients managed the drug over two years.

Combination Therapy Studies

Research has investigated the use of Calegastro in combination with Y therapy to examine outcomes. Preliminary data from a Phase 2 trial suggested that the combined approach was evaluated for its impact on reducing flare-ups. Future research is planned to further examine the long-term outcomes and side effects of combination use.

Common questions about Calegastro (FAQ)

Q: What does this medicine treat? (i.e., its indication)

According to official product information, Calegastro is indicated for the treatment and prevention of recurrence of gastric ulcers in horses and foals that are four weeks of age and older. Its mechanism of action involves reducing gastric acid secretion, which helps create an environment conducive to the healing of tissues in the upper digestive tract.

Q: What happens if I forget to give the dose?

If a dose is missed, regulatory guidance generally advises against doubling the dose or administering extra doses. Consultation with a licensed veterinarian is the recommended step for specific advice on how to handle fully missed doses.

Q: Can I use it in a pregnant mare?

Official safety data has not been established for this product in pregnant or lactating mares. Therefore, its use is formally classified as not recommended during both pregnancy and lactation.

Q: Can I give this to my 50kg foal?

The official product labeling indicates that the use of this medicine is not recommended for foals under four weeks of age. Additionally, the label specifies that use is not recommended for foals weighing less than 70 kg, meaning a 50 kg foal falls outside the recommended eligibility profile.

Q: Is Calegastro available over-the-counter?

No. The product is restricted by regulatory law to use by, or on the order of, a licensed veterinarian. This means Calegastro is exclusively a prescription-only product for veterinary use.

Q: Is the paste designed to be swallowed?

Yes, the paste is an oral product that is designed to be swallowed. It contains enteric-coated microgranules, which are protected by the coating from being destroyed by stomach acid. The coating is designed to protect the active ingredient until it reaches the small intestine, which is necessary for the drug's intended absorption and activity.

Q: Why should I raise my horse's head after giving the dose?

The official administration instructions require raising the horse’s head for several seconds immediately after dosing. This is a mandatory procedural step specified by regulators to help confirm the animal consumes the complete dose and that no part of the paste is lost or rejected.

How to Store and Dispose of Calegastro?

The storage and disposal of Calegastro must strictly follow the requirements documented in official regulatory labeling to ensure product stability and safety.

Official Storage Conditions

Requirement	Rule
Temperature	Store below 25 C (77 F). Do not freeze.
Protection	Protect from light and physical damage.
Container	Store in the original container and keep it tightly sealed when not in use.
Stability	The product is stable for 6 months after the tube has been opened for the first time.

As a mandatory safety requirement, Calegastro must be kept out of the reach of children.

Disposal Instructions

Unused product and waste material must be disposed of in accordance with relevant local regulations. Regulatory documents explicitly state to avoid release to the environment when discarding the product.