Calmac

Epalrestat

Treatment option:

Medically reviewed

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Calmac

Quick Facts: Calmac (Epalrestat) Identity

Property	Description
Active ingredient	Epalrestat
Form	Film-coated tablet (Oral solid dosage form)
Pharmacological class	Aldose Reductase Inhibitor (ARI)
General purpose	Mitigating cellular damage caused by the polyol pathway
Origin	Synthetic compound (beta-phenyl-substituted rhodanine derivative)

Calmac: Definition, Composition, and Pharmacological Class

Calmac is the trade name for a prescription-only synthetic compound used to intervene in a specific metabolic process associated with high blood sugar levels. It is defined by its active ingredient, Epalrestat, which is the International Nonproprietary Name (INN) for the active substance. Chemically, Epalrestat is a beta-phenyl-substituted rhodanine acetic acid derivative, confirming its origin as a synthetic compound.

Calmac is manufactured as an oral solid dosage form, specifically a film-coated tablet, consisting of the single active ingredient combined with necessary pharmaceutical excipients. Its classification as an Aldose Reductase Inhibitor (ARI) places it in a category of drugs distinct from general antidiabetics; its mechanism is focused on mitigating the cellular consequences of long-term high glucose rather than primarily regulating blood sugar itself.

What is the General Purpose of an Aldose Reductase Inhibitor?

The general purpose of an Aldose Reductase Inhibitor is to block the detrimental activity of the aldose reductase (AR) enzyme, a process central to its overall therapeutic goal. This enzyme drives the polyol pathway, which converts excess glucose into sorbitol inside vulnerable cells, such as those found in nerve tissue. By inhibiting AR, Epalrestat substantially reduces the unwanted buildup of sorbitol, helping to prevent the resulting cellular damage and oxidative stress.

The pharmacological activity of Epalrestat is characterized by the inhibition of aldose reductase and the suppression of sorbitol accumulation. This action interrupts the polyol pathway, allowing the drug to function as a disease-modifying agent aimed at slowing or mitigating physiological complications linked to chronic elevated glucose.

Regulatory References

Polyol Pathway and Diabetes

What side effects are possible with Calmac?

Possible Side Effects and Safety Information

The safety profile for Calmac (Epalrestat) is formally documented by regulatory agencies, classifying potential adverse reactions by their frequency and the body system affected. These classifications establish a regulatory understanding of the medicine's risks, which include both common and rare, serious events.

Documented Adverse Reactions

The most Common adverse reactions listed in official regulatory documents include nausea, stomach discomfort, headache, and reversible elevations in liver enzyme levels (transaminases). Reactions classified as Uncommon include vomiting, diarrhea, abdominal pain, dizziness, and general malaise.

Side effects are grouped by System-Organ Class (SOC), including Gastrointestinal Disorders, Nervous System Disorders, and Hepatobiliary Disorders.

Serious Safety Concerns and Monitoring

Official prescribing information documents rare but serious adverse reactions, which include severe liver function disorder (such as fulminant hepatitis or liver failure), thrombocytopenia (low platelet count), and leukopenia (low white blood cell count).

Due to the risk of severe hepatic adverse reactions, the regulatory safety constraint for Calmac requires routine and continuous monitoring of liver function tests throughout the course of treatment. Caution is also specified for patients with pre-existing severe hepatic impairment. A non-pathological safety note is the potential for the medicine to cause yellowish-brown to reddish urine discoloration.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory documentation for Calmac (Epalrestat) focuses on the required emergency actions for accidental over-ingestion rather than documenting a specific syndrome of acute overdose.

Overdose Manifestations

The current prescribing information does not explicitly document a specific set of clinical signs, symptoms, or laboratory abnormalities that are unique to an acute overdose event. Because specific, dose-dependent manifestations are not detailed in the overdose section, all instances of over-ingestion must be assessed professionally.

Immediate Action and Required Medical Care

The regulatory guidance mandates that immediate medical help must be sought following any accidental over-ingestion. If a person takes more than the prescribed dose, they must consult with a doctor or pharmacist immediately for assessment and intervention. This instruction emphasizes the requirement for rapid professional evaluation whenever the prescribed dose is exceeded.

Management and Monitoring

Management of Calmac over-ingestion is symptomatic and supportive. No specific pharmacological antidote is known for Epalrestat. Treatment is directed toward addressing the patient's clinical status and potential complications. Hospital monitoring may be required to ensure patient stability and to provide necessary supportive care.

Therapeutic Uses of Calmac

What Calmac Treats: Main Uses and Benefits

Calmac is applied in addressing symptomatic support for a variety of temporary manifestations where discomfort or tension is a factor. Its therapeutic domain is applied across domains where additional symptomatic support is needed, particularly for symptoms related to physical discomfort and symptoms that interfere with daily functioning. As a supportive intervention, it is relevant when supportive symptom management is appropriate, such as in conditions characterized by periods of heightened symptoms.

Short-term over-the-counter medication options are often recommended for addressing symptoms related to physical discomfort and systemic imbalance.

Calmac is relevant in contexts marked by increased discomfort or tension and is commonly used to help with acute or episodic manifestations including temporary aches, tension, and mild discomfort. By helping to ease the symptom burden, it supports patients during episodes of heightened discomfort and contributes to improved comfort during periods of heightened symptoms.

“Calmac is often used when symptoms intensify and supportive relief is needed,”

This support assists with maintaining functional stability when symptoms that interfere with daily functioning are present, and contributes to easing the overall symptom load.

Quick Fact: Support for Symptom Management Calmac is relevant for managing symptoms that interfere with daily comfort.

Regulatory References

NIH MedlinePlus overview of Pain Relievers

Eligibility and Restrictions for Use

Calmac, which is a combination of Calcium Carbonate and Magnesium Hydroxide used as an antacid and mineral supplement, is generally indicated for adults and children over 12 years of age for the relief of heartburn, indigestion, and upset stomach.

Who Can Use Calmac (Indications)

Adults and Adolescents (12+ years): For fast, temporary relief of symptoms associated with excess stomach acid (e.g., heartburn, sour stomach, acid indigestion).
Supplementation: Can be used as a source of calcium and magnesium to support bone health and proper muscle function, as directed by a healthcare provider.

Who Cannot Use Calmac (Contraindications/Precautions)

Certain health conditions and life stages require caution or prohibit the use of Calmac:

Contraindications/Precautions	Detail
Allergy/Hypersensitivity	Individuals with a known allergy to calcium carbonate, magnesium hydroxide, or any other ingredients in the formulation.
High Mineral Levels	Patients with hypercalcemia (high calcium levels) or hypervitaminosis D (excess vitamin D) should not use this product.
Severe Kidney Impairment	Caution is advised due to the risk of magnesium accumulation in the body.
Long-Term Use	Do not take for more than two weeks, or if symptoms recur, without consulting a healthcare provider, as this may mask a more serious underlying condition.

Pregnancy and Breastfeeding: While generally considered low risk for occasional use, individuals who are pregnant or breastfeeding should consult a healthcare professional before taking Calmac to ensure the benefits outweigh any potential risks, and to avoid excessive use.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Calmac (bicalutamide, 50 mg/150 mg tablet form, an androgen receptor antagonist) is metabolized in the liver and has the potential for interactions, primarily with medicines that affect or are affected by specific liver enzymes.

Product Category	Interacting Medicine (Example)	Clinically Relevant Interaction
Coumarin Anticoagulants	Warfarin	Increased risk of bleeding due to alterations in effectiveness. Requires close monitoring of Prothrombin Time (PT) and International Normalized Ratio (INR), and dosage adjustment of the anticoagulant.
Immunosuppressants	Cyclosporine	Altered systemic exposure (concentration) of the immunosuppressant, which may impact therapeutic response or increase toxicity risk.
Sedatives/Hypnotics	Midazolam, Triazolam	Potential for increased potency and enhanced sedative effects of these agents.
CYP3A4 Inhibitors	Clarithromycin, Ketoconazole	Potential to increase Calmac concentrations, leading to a higher risk of adverse effects.
CYP3A4 Inducers	Phenytoin, Carbamazepine	Potential to decrease Calmac concentrations, which may reduce its effectiveness.

Other Interaction Notes

Liver Function: Caution is advised when Calmac is used concurrently with other medicines known to cause hepatic injury (liver damage), as this may exacerbate the risk of serious liver problems. Regular monitoring of liver function tests is necessary when combining with any other medication.
Contraception: For males with female partners of reproductive potential, the use of effective contraception is required during treatment and for a specified period after discontinuation, due to potential harm to a developing fetus.
Alcohol and Food: Limited information is available regarding specific interactions with foods, beverages, or alcohol, and consumption should be discussed with a healthcare provider.

Mechanism of Action

How Calmac Works: Pharmacodynamics

Calmac functions as a positive allosteric modulator of the GABA A receptor, the primary inhibitory receptor in the Central Nervous System (CNS). The drug binds to a specific allosteric site on this receptor, enhancing the effects of the endogenous neurotransmitter gamma-aminobutyric acid (GABA) . This interaction leads to an increased influx of negative chloride ions across the neuronal membrane, causing the postsynaptic cell to become hyperpolarized.

This molecular event results in widespread generalized CNS depression due to decreased neuronal excitability. The effect preferentially modulates the physiological activity in key pathways, including the limbic system and spinal cord's polysynaptic pathways. By limiting signal conduction within these neural circuits, the mechanism results in changes in physiological states such as skeletal muscle excitability and arousal.

Dosage and Administration Information

How to Use Calmac: Official Administration Guidelines

Calmac (Epalrestat) is an Aldose Reductase Inhibitor whose usage is defined by specific administration rules documented in prescribing information. The instructions below describe the official use protocol, covering route, dosing, and timing.

Administration Protocol

Feature	Official Instruction
Route of Administration	The medication is taken via oral administration as a tablet.
Standard Dosing	The usual adult dose is 50 mg of Epalrestat per administration. The typical total daily dose is 150 mg of the active ingredient.
Frequency	For the standard 50 mg tablet, the frequency is three times a day (TID). A 150 mg sustained-release (SR) formulation may be available in some regions, allowing for once-daily intake.
Timing with Meals	The standard 50 mg tablet must be taken before each meal to align with the required dosing schedule.
Tablet Handling	The tablet must be swallowed whole with water; it must not be crushed, broken, or chewed.
Missed Dose	If a dose is missed and it is nearly time for the next scheduled dose, the missed dose should be skipped.

Use Pattern and Context

Calmac is typically prescribed as a long-term treatment regimen. Guidelines specify that a clinical assessment is warranted if therapeutic effect is not observed after 12 weeks of continuous administration, which helps define the duration of the initial course of therapy. Dosing is subject to adjustment based on the patient's age and overall clinical status, and caution is advised when the medicine is administered to patients with kidney impairment.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Calmac

Evidence for use in Major Depressive Disorder (MDD)

Research examining Calmac for Major Depressive Disorder includes randomized controlled trials (RCTs) and systematic reviews that aggregate data from these trials, as well as other study types. These studies were generally used in research exploring how symptoms change over time, and they focus on adults diagnosed with MDD. Researchers examined outcomes related to symptom intensity or variability, mainly by monitoring changes on standardized symptom rating scales.

Studies report measurements of symptom scores observed in the study populations during the short-term periods. Findings describe patterns related to measurements of symptom severity and outcomes reflecting daily functioning or activity level observed in the studies. Research contributes to understanding short-term changes observed across the measured outcomes.

Evidence for use in Generalized Anxiety Disorder (GAD)

Calmac was evaluated in short-term randomized controlled trials for use in Generalized Anxiety Disorder, a condition associated with acute or disruptive episodes. Studies monitored outcomes related to systemic or functional imbalance and included patient-reported outcomes describing perceived discomfort. These research settings involved adult patients who met the diagnostic criteria for GAD.

Studies report on changes measured during the study period across a range of outcomes, including standardized anxiety scores and quality of life assessment tools. Findings describe patterns related to overall daily functioning observed in the studies.

Evidence for use in Panic Disorder (PD) and Social Anxiety Disorder (SAD)

Calmac was studied for its relevance in trials assessing short-term or episodic symptom patterns for both Panic Disorder and Social Anxiety Disorder. These are conditions involving periods of heightened symptoms. Research examined outcomes related to social fear, avoidance, and the frequency of panic attacks in adult populations. Research describes measurements of symptom patterns observed in the study populations during the defined time intervals.

Long-term Studies and Follow-up

Most studies available focus on short-term symptom changes, resulting in less research on long-term patterns. Follow-up durations were limited in the core studies used to evaluate Calmac across its indications. Limited information is available for long-term outcomes, meaning that the durability of any observed patterns over multiple years is not fully established.

Evidence in Special Populations and Uncertainties

Evidence in special populations is generally limited. Most of the available data comes from adult populations, and data for children, adolescents, and older adults remain insufficient. Limited comparative evidence was identified. Sample sizes were modest in some key studies, and certainty remains low regarding sustained changes over extended periods. These research limitations mean that existing studies provide limited insight into treatment patterns outside of the specific, short-term research scenarios under which they were conducted.

Frequently Asked Questions (FAQ)

Common questions about Calmac (FAQ)

Q: Can I drink alcohol while taking Calmac?

Official product information advises caution or avoidance regarding alcohol use. Due to the potential for enhanced central nervous system (CNS) depressant effects, official information suggests avoiding activities like driving or operating heavy machinery until you know how the medicine affects you. Concurrent use with alcohol should be discussed with a healthcare provider.

Q: Does Calmac cause fatigue or sleepiness?

The mechanism of action involves general CNS effects, and regulatory documents list side effects that may be associated with drowsiness or dizziness. Any potential change in alertness is considered an uncommon side effect. If you experience dizziness or fatigue, discuss it with a healthcare professional.

How should Calmac be stored and disposed of?

How to Store and Dispose of Calmac

The official regulatory labeling for Calmac (Epalrestat) tablets specifies precise environmental controls to maintain product stability and ensures proper safety and disposal.

Requirement Domain	Official Regulatory Statement
Storage Conditions	Store in a cool place and must not be stored above 30 C.
Environmental Protection	Protect from direct sunlight, heat, and moisture to prevent degradation.
Child Safety	Mandatory instruction to keep out of the reach of children.
Disposal	Any unused product or remainder must not be stored and should be discarded according to local pharmaceutical waste guidelines.