Conoxia: Uses, Dosage & Side Effects

What Is Conoxia and What Is It Used For?

Conoxia contains pure oxygen (O₂) at 100% concentration, classified as a medicinal gas for inhalation. Oxygen is an essential element for human survival—every cell in the body requires a continuous supply of oxygen to produce the energy needed for normal metabolic functions through a process called aerobic respiration. Under normal circumstances, atmospheric air contains approximately 21% oxygen, which is sufficient for healthy individuals. However, in many clinical situations, the body’s oxygen demand exceeds what normal breathing can provide, or the lungs are unable to extract enough oxygen from ambient air. In these circumstances, supplemental medical oxygen becomes a life-saving intervention.

The primary mechanism of action of Conoxia is straightforward yet profoundly important: when inhaled at concentrations above ambient levels, it increases the fraction of inspired oxygen (FiO₂), raising the partial pressure of oxygen in the alveoli of the lungs. This enhanced alveolar oxygen tension drives greater oxygen transfer across the alveolar-capillary membrane into the pulmonary blood. Once in the bloodstream, oxygen binds to hemoglobin molecules in red blood cells (each hemoglobin molecule can carry up to four oxygen molecules), increasing arterial oxygen saturation (SpO₂). The oxygen-rich blood is then pumped by the heart to every organ and tissue in the body, correcting tissue hypoxia and supporting normal cellular metabolism.

Conoxia is supplied in compressed gas cylinders that are color-coded according to international standards: the cylinder shoulder is marked white (the international color for oxygen), and the body is white, identifying it as a medicinal gas. Each cylinder is equipped with a pressure regulator that reduces the high storage pressure to a safe, usable flow rate for patient delivery. The gas is odorless, colorless, and tasteless, and no other ingredients or excipients are present in the product.

Uses at Normal Atmospheric Pressure (Normobaric)

Under normal atmospheric pressure, Conoxia has several well-established medical applications. The most common indication is the treatment of acute or chronic hypoxia—a state in which blood oxygen levels fall below the range needed for normal tissue function. Acute hypoxia can occur in a wide range of emergency situations including heart attacks, strokes, severe asthma attacks, pneumonia, pulmonary embolism, major trauma, and sepsis. Chronic hypoxia is seen in progressive lung diseases such as chronic obstructive pulmonary disease (COPD), interstitial lung disease, and cystic fibrosis, where long-term home oxygen therapy may be prescribed to improve quality of life and survival.

Conoxia is also an essential component of general anesthesia and intensive care. During surgical procedures, oxygen is delivered as part of the anesthetic gas mixture to ensure adequate oxygenation while the patient is under sedation and mechanical ventilation. In intensive care units, critically ill patients frequently require supplemental oxygen delivery through various devices including high-flow nasal cannulae, continuous positive airway pressure (CPAP) systems, or mechanical ventilators. The oxygen concentration is carefully titrated based on continuous pulse oximetry and arterial blood gas measurements.

Another important application is using Conoxia to drive nebulizers for the administration of inhaled medications such as bronchodilators (salbutamol, ipratropium) and corticosteroids. In this setting, the oxygen gas flow atomizes the liquid medication into a fine mist that the patient inhales, providing both the therapeutic aerosol and supplemental oxygen simultaneously. This dual benefit is particularly valuable during acute asthma exacerbations and COPD flares.

Conoxia serves as a first-aid treatment for diving accidents, where breathing 100% oxygen at the surface is the standard immediate intervention for suspected decompression illness or arterial gas embolism. Early high-flow oxygen administration helps to wash nitrogen out of tissues and reduce the size of gas bubbles that form during rapid ascent, stabilizing the diver while awaiting definitive hyperbaric treatment.

High-flow oxygen therapy with Conoxia is also an established treatment for acute cluster headache attacks in adults. Clinical evidence, including randomized controlled trials and international guidelines from the European Headache Federation and the American Headache Society, supports the use of 100% oxygen at a flow rate of 12–15 liters per minute through a non-rebreather mask for 15–20 minutes as an effective abortive therapy for cluster headache episodes. This indication is restricted to adults; Conoxia should not be used for cluster headache treatment in children and adolescents.

Uses at High Pressure (Hyperbaric Oxygen Therapy)

Hyperbaric oxygen therapy (HBOT) involves breathing Conoxia at pressures greater than normal atmospheric pressure (typically 2–3 atmospheres absolute) inside a specialized pressure chamber. Under these conditions, the amount of oxygen dissolved directly in the blood plasma increases dramatically—up to 10–15 times normal levels—enabling oxygen to reach tissues even in areas with compromised blood supply where hemoglobin-bound oxygen delivery is insufficient.

The primary hyperbaric indications for Conoxia include decompression sickness (the bends), where dissolved gases form bubbles in tissues during rapid decompression, and arterial gas embolism, where gas bubbles enter the arterial circulation. The elevated pressure physically compresses gas bubbles, reducing their volume according to Boyle’s law, while the high oxygen concentration accelerates nitrogen elimination and promotes bubble reabsorption. HBOT is also a critical treatment for carbon monoxide poisoning, where the extremely high oxygen partial pressure achieved in the chamber competitively displaces carbon monoxide from hemoglobin (carboxyhemoglobin), which has a binding affinity approximately 230 times stronger than oxygen under normal conditions. Additionally, hyperbaric Conoxia is used to treat clostridial myonecrosis (gas gangrene) and other serious anaerobic soft tissue infections, where the elevated tissue oxygen tensions inhibit bacterial growth and enhance immune cell function.

Hyperbaric oxygen therapy with Conoxia can be used in all age groups, though clinical experience in neonates, children, and adolescents is limited, and the benefit-risk ratio should be carefully evaluated for each individual patient.

What Should You Know Before Using Conoxia?

Before beginning oxygen therapy with Conoxia, it is important that your healthcare provider is aware of your complete medical history, current medications, and any conditions that could affect how your body responds to supplemental oxygen. While oxygen is essential for life and generally has an excellent safety profile, there are specific circumstances where its use requires caution or adjustment, and certain situations where hyperbaric administration is contraindicated.

Contraindications

There are no absolute contraindications to the use of normobaric (normal pressure) Conoxia in acute life-threatening situations—oxygen should always be administered when a patient is critically hypoxic. However, for hyperbaric oxygen therapy in a pressure chamber, Conoxia must not be used if you have:

• Untreated pneumothorax: A pneumothorax (collapsed lung due to air leaking into the pleural space) must be treated with a chest drain before hyperbaric therapy, as the pressure changes during compression and decompression could dramatically worsen the pneumothorax, leading to a life-threatening tension pneumothorax.
• Recent surgery or injuries that may have produced gas bubbles in the body: Certain surgical procedures and trauma can introduce air into body cavities or the vascular system, and hyperbaric pressure changes could cause these trapped gas pockets to expand or contract unpredictably, leading to further tissue damage.

Warnings and Precautions

Speak with your doctor before using Conoxia if you have a chronic lung disease such as COPD, chronic bronchitis, emphysema, or severe asthma. In some patients with chronic hypercapnic respiratory failure (where the body has adapted to elevated carbon dioxide levels), the respiratory drive is partly maintained by low oxygen levels rather than high carbon dioxide levels (the so-called “hypoxic drive”). Administering uncontrolled high-flow oxygen to these patients can suppress this drive, potentially leading to respiratory depression, further carbon dioxide retention, and in severe cases, respiratory arrest and loss of consciousness. The British Thoracic Society (BTS) guidelines recommend titrating oxygen in these patients to achieve a target SpO₂ of 88–92% rather than using high-flow oxygen indiscriminately.

Neonates, especially premature infants, are significantly more sensitive to oxygen toxicity than older children and adults. Excessive oxygen exposure in premature babies can cause retinopathy of prematurity (ROP), a condition that can lead to permanent visual impairment or blindness, and bronchopulmonary dysplasia (BPD), a form of chronic lung disease. For this reason, oxygen therapy in neonates must be carefully controlled and monitored, with target SpO₂ ranges typically set between 91–95% in preterm infants, following neonatal resuscitation guidelines from organizations such as the International Liaison Committee on Resuscitation (ILCOR) and the WHO.

If you have been prescribed hyperbaric oxygen therapy, the risk of pneumothorax-related complications (barotrauma) should be carefully considered and assessed before each session. Patients with a history of ear, sinus, or lung problems may be at increased risk of barotrauma during the pressurization and depressurization phases of treatment.

Pregnancy and Breastfeeding

Normobaric oxygen therapy: Conoxia at normal atmospheric pressure can be safely used during pregnancy and while breastfeeding. There are no known adverse effects on the mother, the developing fetus, or the nursing infant when oxygen is administered at standard pressure. Conoxia at normal pressure has no known negative effects on fertility.

Hyperbaric oxygen therapy: If you have been prescribed treatment with Conoxia in a hyperbaric chamber, inform your doctor if you are pregnant or suspect you might be pregnant. There is a theoretical risk that the oxidative stress generated during hyperbaric oxygen exposure could potentially harm the developing fetus. While human data are limited and no clear pattern of birth defects has been established, animal studies have shown some evidence of embryotoxicity at high oxygen pressures, prompting caution.

There are no known adverse effects on breastfeeding from hyperbaric Conoxia use. However, breastfeeding should be avoided during the actual hyperbaric session itself, as the pressurized environment poses risks to the newborn infant. It is safe to breastfeed both before and after hyperbaric treatment sessions. The effects of hyperbaric Conoxia on fertility have not been formally studied.

Driving and Operating Machinery

You may drive after using Conoxia provided your healthcare professional considers you fit to do so. The oxygen therapy itself does not impair driving ability or the operation of machinery. However, if you have been treated in a hyperbaric chamber, mild transient effects such as visual changes (due to lenticular oxygen toxicity) may temporarily affect your ability to drive safely, so follow your treating physician’s advice.

How Does Conoxia Interact with Other Drugs?

Tell your healthcare provider about all medications you are currently taking, have recently taken, or plan to take before starting oxygen therapy with Conoxia. While oxygen is a natural component of the atmosphere and does not undergo hepatic metabolism or renal excretion in the traditional pharmacological sense, several medications and chemicals are known to increase the risk of oxygen-related lung toxicity when combined with supplemental oxygen therapy. These interactions are of particular concern when oxygen is administered at high concentrations (above 50% FiO₂) or for prolonged periods.

The medications of concern are those that can independently cause pulmonary toxicity and have a synergistic damaging effect when combined with elevated tissue oxygen levels. The increased production of reactive oxygen species (ROS)—also known as free radicals—under high-oxygen conditions overwhelms the lungs’ antioxidant defense mechanisms, and these drugs can exacerbate this oxidative damage through various mechanisms.

Major Interactions

Bleomycin is the most clinically significant interacting drug. Bleomycin causes dose-dependent pulmonary toxicity through free radical generation, and exposure to high-concentration oxygen can trigger or worsen bleomycin-induced pulmonary fibrosis even months or years after the last dose of bleomycin. Surgeons and anesthesiologists must be informed of any prior bleomycin exposure before surgery, as even brief intraoperative high-concentration oxygen can be fatal. The general recommendation is to use the minimum FiO₂ necessary to maintain adequate oxygenation in patients with a history of bleomycin treatment.

Amiodarone is a widely used antiarrhythmic drug that can cause pulmonary toxicity independently. When patients on amiodarone therapy are exposed to high concentrations of oxygen, particularly during surgical procedures, there is a significantly increased risk of developing acute respiratory distress syndrome (ARDS). This interaction can occur even at relatively low FiO₂ levels, making careful perioperative oxygen management essential in patients receiving amiodarone.

Paraquat poisoning represents a unique and critical interaction: paraquat is selectively concentrated in lung tissue and produces severe oxidative damage. Administering supplemental oxygen to a patient with paraquat poisoning paradoxically worsens the pulmonary injury by providing additional substrate for free radical generation. Current toxicology guidelines recommend avoiding supplemental oxygen in paraquat-poisoned patients unless oxygen saturation drops below 90%, in which case the minimum necessary oxygen should be provided.

Minor Interactions

The remaining drugs listed (cisplatin, doxorubicin, nitrofurantoin, and disulfiram) carry a moderate risk of enhanced pulmonary toxicity when combined with prolonged high-concentration oxygen. In clinical practice, these interactions are managed by using the lowest effective oxygen concentration, limiting the duration of oxygen exposure where possible, and monitoring respiratory function closely. Always inform your doctor about any current or recent use of these medications before starting oxygen therapy.

What Is the Correct Dosage of Conoxia?

Always use Conoxia exactly as described in the patient information leaflet or as directed by your healthcare provider. Do not change the prescribed dose without consulting your doctor first. If you are using this medicine at home, you will receive thorough instructions during the first delivery on how to use Conoxia and the associated equipment safely and effectively.

Conoxia is administered by inhalation. Patients typically breathe through a nasal cannula (a lightweight tube with two prongs that rest inside the nostrils), a face mask (a simple mask covering the nose and mouth), or a non-rebreather reservoir mask (which delivers the highest oxygen concentration through a bag reservoir). Patients may breathe spontaneously or receive assisted breathing through a mechanical ventilator or respiratory support device. Always read and follow the operating instructions provided with your specific breathing equipment.

Adults

For most acutely ill adult patients, the BTS guidelines recommend an initial target oxygen saturation of 94–98%. For patients at risk of hypercapnic respiratory failure (such as those with severe COPD, morbid obesity, chest wall deformities, or neuromuscular disease), the recommended target is 88–92%. Oxygen therapy should be adjusted by titrating the flow rate up or down to maintain the patient within their target saturation range.

For acute cluster headache, the recommended dose is 100% oxygen at 12–15 L/min via a non-rebreather mask for 15–20 minutes at the onset of a headache episode. If the headache does not resolve, treatment can be continued for up to 30 minutes. This should only be used in adults.

For diving emergencies, 100% oxygen at the highest available flow rate should be administered immediately via a tight-fitting non-rebreather mask and continued during transport to a hyperbaric facility.

Children

Children of all ages can be treated with normobaric Conoxia. Dosing in children follows the same principles as in adults: oxygen is titrated to achieve and maintain target oxygen saturations appropriate for the child’s age and clinical condition. Special care must be taken with neonates, particularly premature infants, as described in the warnings section. In neonatal resuscitation, current international guidelines recommend starting resuscitation with room air (21% oxygen) for term babies and 21–30% for preterm babies, only increasing the FiO₂ if the infant fails to achieve target saturations by specific time points.

Children of all ages can also receive hyperbaric Conoxia therapy. The treatment duration and frequency are determined by the treating physician based on the child’s specific condition and clinical response. Conoxia should not be used for the treatment of cluster headache attacks in children and adolescents.

Elderly

Elderly patients can use Conoxia at the same doses as younger adults. However, older adults have a higher prevalence of chronic respiratory conditions and are more likely to have multiple comorbidities that may influence oxygen management. Close monitoring of oxygen saturation and respiratory status is recommended, particularly in elderly patients with COPD or other chronic lung diseases where the risk of hypercapnic respiratory failure is elevated.

Missed Dose

Oxygen therapy is typically administered continuously or intermittently as needed to maintain target oxygen saturations. There is no concept of a “missed dose” in the traditional sense. If you are on home oxygen therapy and have interrupted your treatment, simply resume your prescribed oxygen therapy as soon as possible. If you are uncertain about your treatment schedule, consult your healthcare provider.

Overdose

Oxygen overdose (oxygen toxicity) can occur if you use more Conoxia than prescribed, particularly at high concentrations over prolonged periods. Symptoms of oxygen toxicity may include:

• Chest pain and discomfort behind the breastbone
• Dry, persistent cough
• Shortness of breath (paradoxically worsening)
• Impaired lung function
• In patients with chronic lung disease: respiratory depression, carbon dioxide retention, and reduced consciousness

Prolonged exposure to oxygen concentrations above 70% for more than 6–12 hours can begin to cause tracheobronchial irritation and, in severe cases, may lead to acute respiratory distress syndrome (ARDS) and pulmonary fibrosis. If you notice any signs of oxygen toxicity, contact your healthcare provider immediately. If you experience severe symptoms such as marked difficulty breathing, confusion, or loss of consciousness, seek emergency medical attention at once.

What Are the Side Effects of Conoxia?

Like all medicines, Conoxia can cause side effects, although not everybody experiences them. Side effects are generally observed only when oxygen is administered at high concentrations (above 70% FiO₂) for extended periods of time (typically at least 6–12 hours of continuous exposure). At lower concentrations and shorter durations, side effects are uncommon. The risk and severity of side effects depend on the oxygen concentration, duration of exposure, and individual patient factors.

Side Effects at Normal Pressure (Normobaric)

The most serious side effect that can occur with normobaric oxygen therapy is acute respiratory distress syndrome (ARDS), which can progress to pulmonary fibrosis if oxygen toxicity is not recognized and addressed promptly. If you experience worsening difficulty breathing during oxygen therapy, stop the treatment and seek immediate medical attention.

Side Effects at High Pressure (Hyperbaric)

When Conoxia is administered in a hyperbaric chamber, the side effect profile differs somewhat from normobaric use due to the effects of pressure changes and the higher tissue oxygen levels achieved. The most serious hyperbaric side effects are confusion and seizures (central nervous system oxygen toxicity). Medical personnel are always present during hyperbaric treatment and will take immediate action if any of these side effects occur.

Additional Side Effects in Children

Special caution is required when treating neonates with Conoxia, as they are more sensitive to certain side effects than older children and adults. The most serious side effects in neonates are:

• Retinopathy of prematurity (retrolental fibroplasia): Excessive oxygen exposure can cause abnormal blood vessel growth in the developing retina of premature infants, potentially leading to retinal detachment and permanent visual impairment or blindness.
• Bronchopulmonary dysplasia (BPD): Prolonged oxygen exposure combined with mechanical ventilation can cause chronic lung disease in premature neonates, leading to long-term respiratory problems.

If you suspect your child has developed any of these side effects, discontinue treatment and contact your doctor immediately. Apart from these neonatal-specific risks, children and adolescents may experience the same side effects as those reported in adults.

For hyperbaric therapy, there are no additional known side effects in children beyond those reported in adults.

How Should You Store Conoxia?

Proper storage of Conoxia gas cylinders is essential for both safety and maintaining the quality of the medicinal product. Compressed gas cylinders contain oxygen under high pressure and must be handled and stored with appropriate care to prevent accidents and ensure the gas remains suitable for medical use.

• Keep out of sight and reach of children – gas cylinders are heavy objects under high pressure and should be secured in an area inaccessible to children.
• Store in a well-ventilated area – do not store cylinders in enclosed, poorly ventilated spaces where oxygen could accumulate to dangerous concentrations.
• Protect from heat – do not expose cylinders to strong heat, direct sunlight, or temperatures above the manufacturer’s recommended limits, as heat causes the gas pressure inside the cylinder to increase.
• Keep cylinders clean and dry – avoid contamination of cylinder valves and fittings with dirt, dust, or moisture.
• Prevent impact and falls – always secure cylinders upright in an appropriate stand or bracket, and handle them carefully to prevent drops or collisions that could damage the valve assembly.
• Store away from flammable materials – oxygen supports combustion, so cylinders must be stored well away from fuels, oils, greases, solvents, and other flammable substances.
• Close the valve when not in use – always close the cylinder valve completely and attach the protective cap and cover (where provided) when the cylinder is not actively being used.
• Check the expiration date – do not use Conoxia after the expiry date printed on the label (EXP). The expiry date refers to the last day of the indicated month.
• Do not use if the seal is broken – if the gas cylinder does not have an intact seal when delivered, do not use it and contact your supplier immediately.
• Return empty cylinders – used or empty cylinders should be returned to the supplier for refilling or proper disposal; do not attempt to refill cylinders yourself.

What Does Conoxia Contain?

Conoxia is a uniquely simple pharmaceutical product. The active substance is oxygen (O₂) at 100% concentration. There are no excipients, preservatives, stabilizers, propellants, or other inactive ingredients of any kind. The cylinder contains only pure, medical-grade oxygen that meets the requirements of the European Pharmacopoeia.

Oxygen is a diatomic molecule (O₂) with a molecular weight of 32 g/mol. At room temperature and atmospheric pressure, it is a colorless, odorless, and tasteless gas. It is slightly denser than air (density approximately 1.43 g/L at 0°C and 1 atm) and is moderately soluble in water. Oxygen is a powerful oxidizing agent and vigorously supports combustion, which is why strict fire safety precautions are essential.

Cylinder Identification and Sizes

Conoxia gas cylinders are identified by internationally standardized color coding: the cylinder shoulder is white (indicating oxygen) and the cylinder body is white (indicating a medicinal gas). Cylinders are filled to pressures of 200 bar, 153 bar, or 138 bar depending on the cylinder type, and are available in a wide range of sizes to suit different clinical and home-use settings.

Not all cylinder sizes may be marketed in all countries. The cylinder choice depends on the clinical setting, flow rate requirements, and expected duration of use. For home oxygen therapy, smaller portable cylinders (2–5 L) are typical, while hospitals generally use larger cylinders (10–50 L) or centralized piped oxygen supply systems.

Conoxia is manufactured and distributed by Linde Healthcare, a division of Linde plc, one of the world’s largest industrial and medical gas companies. The product is authorized throughout the European Economic Area under the name Conoxia in multiple countries including Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, Norway, and Sweden.