Sodium cromoglicate

MECHANISM OF ACTION

Sodium cromoglicate is a mast cell stabilizer that prevents the release of inflammatory mediators, such as histamine, from mast cells. Its mechanism is thought to involve inhibiting calcium influx into mast cells, thereby preventing degranulation and the release of substances that trigger allergic reactions and asthma symptoms. Additionally, it may block nerve signaling and exert effects on other cells and inflammatory pathways.

PHARMACOKINETICS

Absorption

Sodium cromoglicate is poorly absorbed from the gastrointestinal tract and the eye, with less than 1% of an oral dose reaching systemic circulation. In contrast, it is well absorbed when inhaled or administered intranasally, allowing rapid delivery to the lungs or nasal passages. Once in the systemic circulation, it is not metabolized and is rapidly excreted unchanged in the urine and bile.

Distribution

The apparent volume of distribution of sodium cromoglicate in humans is approximately 0.2 L/kg. 

Metabolism

Sodium cromoglicate is not metabolized in the body. After absorption, it remains chemically unchanged and is eventually excreted unchanged via the urine and bile, contributing to its predictable pharmacokinetics.

Excretion

Sodium cromoglicate is primarily excreted unchanged in the feces and urine, with the majority of an oral dose remaining unabsorbed. Following inhalation, absorption into the lungs is much higher, and the drug is rapidly cleared via the urine and bile. 

PHARMACODYNAMICS

Sodium cromoglicate works by stabilizing mast cells, preventing the release of inflammatory mediators such as histamine and leukotrienes, and inhibiting mast cell degranulation that triggers allergic reactions. It also exerts anti-inflammatory effects on cells like macrophages and eosinophils and can block nerve signals, helping to reduce symptoms such as itching, bronchoconstriction, and other allergic manifestations.

ADMINISTRATION

Sodium cromoglicate can be given orally (capsules), as eye drops, nasal spray, or inhaled solution for respiratory conditions. Oral doses are usually taken 15–30 minutes before meals, eye drops are applied directly to the eyes, and inhalers or nebulizers are used to deliver the drug to the lungs for asthma or other respiratory issues.

DOSAGE AND STRENGTH

Sodium cromoglicate is available in multiple forms with varying strengths depending on the route of administration:

Oral (capsules): 20 mg, typically 2–4 times daily for allergy prevention.

Eye drops: 2% or 4% solutions, usually 1–2 drops in the affected eye 4–6 times daily.

Nasal spray: 10 mg per spray, typically 1–2 sprays per nostril 4 times daily.

Inhalation/nebulizer solution: 20 mg per vial, usually 4 times daily, depending on the severity of respiratory symptoms.

DRUG INTERACTIONS

Sodium cromoglicate has few significant drug interactions due to its minimal systemic absorption. Caution is advised when using multiple inhaled, nasal, or ocular medications simultaneously, as they may affect local absorption or effectiveness. When combining with beta-agonists, corticosteroids, or other eye drops, proper timing and technique should be observed to ensure optimal therapeutic effect.

FOOD INTERACTIONS

Sodium cromoglicate has minimal food interactions because it is poorly absorbed orally. However, for oral capsules, it is recommended to take the medication 15–30 minutes before meals to maximize absorption and effectiveness. Other forms like eye drops, nasal sprays, or inhalation solutions are not affected by food intake.

CONTRAINDICATIONS

Sodium cromoglicate is contraindicated in patients with known hypersensitivity to sodium cromoglicate or any of its excipients, as allergic reactions such as rash, urticaria, or anaphylaxis may occur. There are no other absolute contraindications, but caution is advised in patients with severe renal or hepatic impairment due to limited safety data. It should also be used carefully in individuals who may have difficulty using inhalers, nasal sprays, or eye drops correctly, as improper administration can reduce effectiveness. Although sodium cromoglicate is generally considered safe during pregnancy and breastfeeding, it should be used only when clearly indicated and under medical supervision.

SIDE EFFECTS

Common (usually mild and transient):

• Throat irritation or cough (inhaled form)

• Hoarseness or dry mouth/throat

• Nasal irritation, sneezing, or mild burning (nasal spray)

• Transient stinging, burning, or blurred vision (eye drops)

• Nausea, abdominal discomfort, or diarrhea (oral form)

Uncommon:

• Headache or dizziness

• Unpleasant taste after inhalation or nasal use

Rare:

• Skin rash, urticaria, or itching

• Angioedema or bronchospasm

• Systemic hypersensitivity or anaphylactic reaction (very rare)

OVERDOSE

• Headache

• Diarrhea

• Nausea and vomiting

• Abdominal pain/discomfort

• Coughing and wheezing

• Nasal congestion or irritation

• Sneezing

• Skin rash or itching

• Joint pain

• Temporary stinging/burning sensation (if using eye drops)

• Irritability or insomnia 

TOXICITY

Sodium cromoglicate has a very low toxicity profile and is considered extremely safe for both short- and long-term use. Because it is poorly absorbed from the gastrointestinal tract and has minimal systemic absorption when used by inhalation, nasal, or ocular routes, toxic effects are rare. In cases of accidental overdose, symptoms are usually mild and may include nausea, headache, or gastrointestinal discomfort. Serious or life-threatening toxicity is extremely uncommon. There is no specific antidote for sodium cromoglicate overdose, and management is mainly supportive and symptomatic. Long-term use has not been associated with cumulative toxicity or organ damage, making it a well-tolerated medication with a wide margin of safety.