Romilar AC

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Romilar AC

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

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 Romilar AC

Romilar AC is a combination pharmaceutical preparation formulated for the concurrent symptomatic relief of cough and chest congestion caused by minor bronchial irritations, such as those associated with the common cold. It addresses both symptoms through its dual-action mechanism.


Quick Facts: Romilar AC Identity

Property Description
Active Ingredients Codeine Phosphate, Guaifenesin
Form Oral Solution (Syrup)
Pharmacological Class Antitussive and Expectorant Combination
Common Use Symptomatic relief of cough and chest congestion
Origin Semisynthetic Opioid Derivative (Codeine) + Synthetic Compound (Guaifenesin)

Composition and Classification

Romilar AC contains two active ingredients: Codeine Phosphate and Guaifenesin. The preparation is classified as an Opioid-Containing Antitussive and Expectorant Combination, reflecting its structural composition. Codeine is a semisynthetic opioid derivative that acts as the cough suppressant, while Guaifenesin is a synthetic compound that functions as the expectorant. This dual composition allows the medicine to target both the urge to cough and the viscosity of respiratory secretions.

Dual Action and General Purpose

The core purpose of Romilar AC is rooted in the complementary nature of its constituents. The Codeine component works to dampen the cough reflex, which helps to reduce the frequency and intensity of persistent coughing fits. Concurrently, Guaifenesin acts within the airways to help thin and loosen thick mucus and phlegm, thereby assisting the body in the efficient clearance of secretions. This integrated mechanism provides comprehensive symptomatic relief for an irritating cough that is accompanied by chest congestion due to excessive, viscous secretions.

What side effects are possible with Romilar AC?

The official safety profile of Romilar AC (Codeine Phosphate and Guaifenesin) is primarily structured around the regulatory requirements and documented effects of the opioid component, Codeine. Adverse reactions and safety constraints are classified across several physiological systems according to regulatory documents.

Officially Classified Adverse Reactions

Adverse reactions are grouped according to the system-organ classes (SOC) as categorized in regulatory documentation:

System-Organ Class (SOC) Documented Adverse Reactions Frequency Classification
Gastrointestinal Disorders Constipation, Nausea, Vomiting Common (Constipation)
Nervous System Disorders Drowsiness, Dizziness, Sedation Common (Drowsiness)
Respiratory Disorders Respiratory Depression (Serious) Serious Risk

Drowsiness and constipation are frequently cited as common adverse reactions. Less frequent effects, sometimes classified as Not Known, include headache, confusion, restlessness, rash, and urinary retention.

Serious Safety Considerations and Regulatory Warnings

Official regulatory documents emphasize the serious and potentially life-threatening risks associated with the Codeine component:

  • Respiratory Depression: A severe or fatal slowing of breathing is a documented risk, which is noted to be most significant at the initiation of treatment or following a dose increase.
  • Physical Dependence and Abuse: The medication is classified as a controlled substance, and misuse carries the risk of abuse, addiction, and physical dependence.
  • Hypersensitivity: Severe allergic reactions, including swelling (angioedema), are possible.

Population-Specific Safety Notes

  • Pediatric Safety: The use of Codeine-containing medicines for cough/cold symptoms is restricted and generally not recommended in children under 18 years of age due to the serious risk of respiratory depression.
  • Older Adults: Serious side effects, particularly central nervous system effects, may be more likely in older adult patients.
  • Pregnancy and Lactation: Prolonged use during pregnancy may cause neonatal opioid withdrawal syndrome. Breastfeeding is generally not recommended due to the risk of serious adverse reactions in the nursing infant.

Overdose and Emergency Response

Overdose and when to seek help

The overdose profile for Romilar AC is defined by the severe effects of its codeine component, necessitating immediate emergency action as stated in regulatory guidance.

Documented Clinical Manifestations Overdose manifestations described in regulatory documents primarily involve Central Nervous System (CNS) depression, characterized by severe drowsiness, stupor, and confusion. Other signs include pinpoint pupils (miosis) and cold, clammy skin. The most critical manifestation is respiratory depression, involving slow, shallow, or stopped breathing (apnea), alongside cardiovascular effects like low blood pressure and slowed heart rate.

Required Emergency Actions and Monitoring Overdose is classified as a life-threatening event with the potential for fatal outcomes due to respiratory arrest. Regulators mandate that immediate emergency medical attention must be sought if any symptoms of overdose occur. Urgent help is required specifically if an individual exhibits slow or shallow breathing, is hard to wake up, or shows signs of bluish discoloration of the lips or fingers. The treatment protocol involves the administration of an opioid antagonist for reversal and continuous monitoring of respiratory status.

Population-Specific Risk The official labeling highlights a high risk in certain groups, particularly children, in whom severe respiratory depression and death are documented outcomes. Individuals identified as ultra-rapid metabolizers of codeine are also listed as being at increased risk.

Therapeutic Uses of Romilar AC

What Romilar AC Treats: Main Uses and Benefits

Romilar AC is commonly used across therapeutic domains where short-term symptomatic assistance is needed to manage the acute respiratory symptoms of illnesses like the common cold and flu. It is commonly used to offer supportive relief for respiratory discomfort arising from minor throat and bronchial irritation. This medication is indicated to temporarily relieve cough and help loosen phlegm and thin secretions.

The medication is applied in clinical settings that involve acute or unstable symptom patterns, helping to address symptom clusters that may become intense or disruptive, such as a persistent, irritating cough and uncomfortable chest congestion caused by thick mucus. It supports the patient during difficult episodes by easing distress. The medicine plays a role in offering supportive relief.

“It is relevant when supportive symptom management is appropriate, particularly when cough and congestion interfere with daily comfort.”

Quick Fact: Relief for Dual Symptoms

Symptom Domain Primary Therapeutic Action
Irritating Cough Provides temporary management of the cough reflex.
Chest Congestion Supports the thinning and loosening of viscous secretions.

Regulatory References

  1. DailyMed Label Information on Codeine Phosphate and Guaifenesin

Eligibility and Restrictions for Use

Who Can and Cannot Use Romilar AC?

Eligibility for Romilar AC (Codeine Phosphate and Guaifenesin combination) is strictly defined by regulatory authorities based on age, specific medical conditions, and physiological status. The medicine is primarily intended for use by adults 18 years of age and older who do not have any contraindications.


Absolute Non-Eligibility (Contraindicated)

Individuals who must not use this medicine include:

  • Children younger than 12 years of age.
  • Patients with known hypersensitivity to any of the ingredients.
  • Patients with significant respiratory depression, severe bronchial asthma, or a history of paralytic ileus.
  • Anyone concurrently using a Monoamine Oxidase Inhibitor (MAOI) or within 14 days of stopping an MAOI.
  • Patients known to be ultra-rapid metabolizers of codeine.

Populations Requiring Caution or Restriction

Use is not recommended in breastfeeding women and requires professional consultation due to risks to the infant. Pregnant women should avoid use. Caution and monitoring are necessary for patients with severe hepatic impairment or severe renal impairment, as well as those with chronic pulmonary disease.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The official interaction profile for Romilar AC is principally defined by the Codeine component, involving both pharmacokinetic and pharmacodynamic interactions documented in regulatory labeling.

Contraindicated Combinations and Timing Restrictions

Co-administration with Monoamine Oxidase Inhibitors (MAOIs) is formally contraindicated due to the risk of severe opioid potentiation. Administration of Romilar AC must not occur concurrently or within 14 days of stopping an MAOI.

Pharmacodynamic and Metabolic Interactions

Interaction Type Interacting Categories (Examples) Official Outcome
Additive CNS Depression CNS Depressants (Benzodiazepines), Alcohol Risk of profound sedation, respiratory depression, coma, and death.
Metabolic Inhibition (CYP2D6) CYP2D6 Inhibitors (Fluoxetine) May reduce antitussive efficacy by decreasing active metabolite formation.
Metabolic Inhibition (CYP3A4) CYP3A4 Inhibitors (Antifungals) May increase Codeine plasma concentration, raising the risk of opioid toxicity.
Serotonin Potentiation Serotonergic Drugs (SSRIs, SNRIs) Documented risk of Serotonin Syndrome.

Population-Specific Cautions

Regulatory documents note that CYP2D6 Ultrarapid Metabolizers are at increased risk of serious adverse effects when co-administered with other interacting agents due to rapid conversion of Codeine to its active metabolite, Morphine.

Mechanism of Action

Central Cough Reflex Inhibition

This domain addresses the involuntary signaling of the cough reflex. The active ingredient Codeine, after conversion by the enzyme CYP2D6 into its more potent metabolite, acts as an agonist at central mu-opioid receptors ( MOR) in the brainstem. This molecular interaction dampens the afferent signal processing within the cough-coordinating center, leading to a physiological state where a stronger stimulus is required to activate the reflex. The physiological consequence is an elevation of the cough threshold and a resultant decrease in neuronal output from the cough center.


Neurogenic Airway Secretion Modulation

This domain addresses the physical properties of airway secretions. Guaifenesin acts as a mild stimulant to vagal afferent receptors in the stomach lining, triggering an autonomic reflex pathway. This reflex leads to increased fluid secretion from the submucosal glands in the respiratory tract. The resulting physiological effect is the dilution and reduction in viscosity of the bronchial mucus, which facilitates the action of the mucociliary apparatus.

Dosage and Administration Information

How to Use Romilar AC: Official Administration Guidelines

Romilar AC (Codeine Phosphate and Guaifenesin Oral Solution) is administered according to specific guidelines focused on accurate measurement and short-term use. The medicine is taken exclusively via the oral route as a liquid solution. Its use is defined by specific dosing limits and administration constraints to ensure adherence to the labeled regimen.


Administration Scope

Field Instruction
Dosing Schedule The standard single dose for adults and children 12 years and over is 10 mL.
Frequency Pattern Administer every 4 hours, as needed for symptoms.
Maximum Daily Limit Administration must not exceed 6 doses (or 60 mL) within a 24-hour period.
Course Duration The medication is intended for short-term use only. Treatment should be discontinued if symptoms persist or do not improve within 7 days.
Measurement & Timing The dose must be measured with an accurate milliliter-specific dosing device; household spoons are not to be used. The medicine may be taken with or without food.

Population and Procedural Rules

Age-Group Administration: Standard dosing is indicated for adults and children 12 years of age and over. Use in children under 12 years of age is generally not recommended due to associated risks.

Missed-Dose Protocol: If a dose is missed, the patient should skip that dose if the time for the next scheduled dose is near. The protocol specifies that double or extra doses must not be taken to compensate.

This structured protocol emphasizes accurate volume control and strict frequency adherence, ensuring the usage aligns with the established guidelines for this combination medicine.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Romilar AC


Evidence for Use in Acute Cough and Chest Congestion

The evidence base for Romilar AC, a combination of antitussive and expectorant ingredients, consists of research exploring its use in conditions associated with acute or disruptive episodes, such as cough and chest congestion arising from the common cold or flu. The research landscape primarily includes short-term Randomized Controlled Trials (RCTs) and comprehensive Systematic Reviews that consolidate data from multiple investigations.

Research examined outcomes related to patient-reported perceived discomfort, specifically focusing on the frequency and intensity of coughing fits. Across the evidence base, findings were mixed regarding the antitussive component (Codeine) in this context. While some studies reported patterns observed related to temporary changes in symptoms, authoritative systematic reviews often note that the evidence is limited or that the observed patterns may not be significantly different from those reported by the placebo group. This area of research contributes to the broader evidence landscape but does not provide definitive certainty regarding outcomes.


Duration of Study and Follow-up Periods

The research available for Romilar AC and similar combination products was studied for short-term or episodic symptom patterns. The duration of observation periods in key studies was follow-up durations were limited. This includes single-dose assessments, where patient-reported outcomes were observed in just a few hours, up to multi-day trials spanning a few days. Because the research primarily focuses on short-term symptom patterns, there is limited information for long-term outcomes or durability of any observed response.


Research in Specific Adult and Adolescent Populations

The key clinical research that informs the evidence for Romilar AC was evaluated in Adults (18 years and older) with uncomplicated upper respiratory infections. While earlier research included adolescents, the current evidence base for efficacy and safety is largely focused on adult populations, which aligns with population suitability considerations observed in regulatory reviews. Results apply only to the populations studied, and there is limited information to generalize findings to populations outside of adults with uncomplicated, acute symptoms.


Evidence Quality and Key Research Limitations

The overall quality of the evidence base for acute cough relief using combination products like Romilar AC is described by systematic reviewers as low certainty. Key structural limitations have been noted, including modest sample sizes in some comparative trials and high variability across studies in terms of assessment methods. The available evidence highlights what is known—and what is still uncertain.

Key Studies & References

  1. Guaifenesin and Codeine Phosphate Oral Solution USP - DailyMed (NIH)
  2. Cough (acute): antimicrobial prescribing - NICE Guideline NG120 (Summary of the evidence)

Frequently Asked Questions (FAQ)

Common questions about Romilar AC (FAQ)

Q: What is the main difference between Romilar AC and a cough medicine that doesn't require a prescription?

According to official product information, the main difference is that Romilar AC contains Codeine Phosphate, an opioid cough suppressant. The inclusion of this ingredient means the medicine is classified as a controlled substance by regulatory authorities. This classification is the main distinguishing factor from most non-prescription cough and cold products.

Q: How quickly should I expect Romilar AC to start relieving my cough?

The official directions specify that a dose is taken every four hours, as needed for symptoms, indicating the therapeutic duration. However, the exact time it takes for the cough relief to begin (onset of action) is not explicitly detailed in the consumer-facing drug information.

Q: Can Romilar AC be used if my cough is caused by a common cold, or only allergies?

Official indications state that this medicine is used to temporarily relieve cough caused by minor throat and bronchial irritation. This irritation is often associated with conditions like the common cold or upper respiratory allergies, such as hay fever.

Q: What signs of breathing trouble should I watch out for while taking Romilar AC?

Regulatory documents warn that signs of a potentially serious adverse reaction include difficult, noisy, or shallow breathing, or unusual confusion and sleepiness. If any of these signs of breathing trouble occur, the official documentation advises that emergency medical attention should be sought.

Q: Is Romilar AC safe for use in older adults (geriatric population)?

Official warnings indicate that use of this medicine requires caution in older adults. This is because they may be more sensitive to certain side effects of Codeine, particularly central nervous system effects such as dizziness and confusion.

Q: Is it possible to become sensitive to Romilar AC after taking it multiple times?

The drug label includes a general warning about the possibility of severe allergic reactions, which are known as hypersensitivity reactions. However, official information does not specifically state whether this sensitivity can be acquired or intensified after taking the medicine multiple times.

Q: Does Romilar AC affect the ability to operate machinery or drive?

According to official regulatory warnings, the medicine may cause severe dizziness and drowsiness due to its effects on the central nervous system. The warnings state that patients should not drive or operate machinery until they are aware of how the medicine affects them.

Q: Can Romilar AC worsen or change my mood, such as causing confusion or unusual thoughts?

The official list of potential adverse reactions includes effects on the nervous system. Documented mental changes include confusion, restlessness, and unusual sleepiness.

Q: Is Romilar AC known to cause allergic reactions, and what are the signs?

Severe allergic reactions, known as hypersensitivity, are listed as possible risks. Swelling (angioedema) is a documented sign of this reaction. The product label states that patients should discontinue use and consult a healthcare professional if symptoms like a rash, fever, or persistent headache occur.

Q: Are there any specific foods I should avoid while using Romilar AC?

Official counseling information includes a statement regarding the consumption of grapefruit and grapefruit juice due to the potential for these products to affect how Codeine works in the body.

Q: Can I experience withdrawal symptoms if I stop taking Romilar AC suddenly?

The official protocol addresses the risk of physical dependence with prolonged use. Patient counseling indicates that if the medicine is discontinued, the dosage may be slowly tapered to manage the risk of side effects associated with stopping treatment.

Q: Is Romilar AC ever used for purposes other than cough and congestion?

Official indications strictly limit the purpose of this combination medicine to the temporary relief of cough and chest congestion. The regulatory documents do not include other uses for this product.

Q: Can Romilar AC cause severe dizziness or fainting when standing up too quickly?

Official warnings indicate that the medicine may cause orthostatic hypotension, which is a drop in blood pressure that occurs when changing position (e.g., standing up from sitting). This condition can result in feelings of dizziness, lightheadedness, or fainting.

Q: Is it safe to take other cold medications (like decongestants) with Romilar AC?

According to official interaction warnings, taking Romilar AC with other cold medicines can increase the risk of serious side effects. This risk is especially high with medicines that cause drowsiness, such as antihistamines or certain decongestants, due to the potential for profound sedation and respiratory depression.

Q: Can Romilar AC be used if I have a history of sleep apnea?

Regulatory warnings advise that the use of this medicine is generally not recommended in patients with obstructive sleep apnea (OSA). This is due to the potential for an increased risk of severe respiratory depression.

Q: If I have mild asthma or COPD, can I still use Romilar AC?

Official drug labels caution against using this product if you have a persistent cough or a chronic pulmonary disease like asthma or COPD. The labels state that a consultation with a healthcare professional is required before use for individuals with these conditions.

Q: Are there any common over-the-counter pain relievers that should not be taken with Romilar AC?

Official interaction documents warn against taking Romilar AC with other medicines that cause central nervous system (CNS) depression. This includes some pain relievers that cause drowsiness or sedation, as combining them can lead to dangerously additive effects.

Q: Can Romilar AC interact with supplements or herbal remedies?

Regulatory counseling includes a statement about the need to inform a healthcare professional of all supplements and herbal products being used, as certain components may have the potential to interact with the medication.

Q: Does Romilar AC contain alcohol, sugar, or dyes?

The presence of inactive ingredients like alcohol, sugar, or dyes varies depending on the specific product formulation and manufacturer. The content of inactive ingredients must be verified by referring to the specific product’s labeling.

Q: Can taking Romilar AC affect the results of an upcoming drug screening test?

The active ingredient, Codeine, is an opioid that is classified as a controlled substance. When processed by the body, Codeine metabolizes into morphine, and both substances are commonly targeted in drug screening tests.

Q: Why is the drug not recommended for people who have had tonsil or adenoid surgery?

Regulatory documents include a Boxed Warning and Contraindication against using this drug in children following tonsillectomy or adenoidectomy. This is due to a documented risk of life-threatening respiratory depression in this specific population.

Q: Can Romilar AC cause dry mouth, and is this a common side effect?

Dry mouth is a documented side effect associated with the Codeine component of the medicine. Official documentation lists it among potential adverse reactions, often noting that the incidence frequency is not known or less common.

Q: If I have high blood pressure, is Romilar AC still appropriate for my cough?

The Warnings section of the drug label requires a consultation with a healthcare professional before use for individuals with high blood pressure.

Q: What is the risk of using Romilar AC if I have a history of seizures?

Regulatory documents indicate that a history of seizures is a medical condition requiring careful assessment by a healthcare professional prior to initiating use of this medicine.

Q: What information should I provide to a pharmacist or doctor before starting Romilar AC?

Regulatory guidance indicates that a complete medical history should be provided to a healthcare professional. This history includes all current prescription medicines, over-the-counter drugs, vitamins, supplements, and herbal products to address potential interactions or risks.

Q: Can Romilar AC cause a change in my heart rate or pulse?

A slow heartbeat is documented in official information as a potential symptom of overdose. Furthermore, the Warnings section states that consultation with a healthcare professional is required prior to use for patients with heart disease.

Q: Can the effectiveness of Romilar AC decrease over time with repeated use?

The official patient counseling addresses the potential for a decrease in effectiveness with repeated use. Regulatory guidance states that if the medicine feels less effective over time, a healthcare professional should be consulted for further instructions.

How should Romilar AC be stored and disposed of?

Romilar AC, an oral solution containing Codeine Phosphate and Guaifenesin, must be stored and disposed of according to official regulatory requirements, primarily due to its controlled substance classification.

Official Storage Requirements

The medication must be stored at Controlled Room Temperature, which is generally 20°C to 25°C ( 68°F to 77°F), with temporary excursions permitted between 15°C and 30°C ( 59°F to 86°F). It must be protected from excess heat and moisture, and kept in a tightly closed, light-resistant container.

Child-Safety and Disposal

Official labeling mandates that the product be stored in a safe place and kept out of the reach of children to prevent misuse and accidental ingestion. Unused or expired medication should be discarded using an authorized drug take-back program. The product must not be flushed down the toilet or disposed of in household waste.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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