Gefapixant Citrate

Introduction: Gefapixant is a selective antagonist of the P2X3 receptor. P2X3-containing receptors belong to the family of purinergic receptors and are ATP-dependent ion channels, which are also located on sensory C-fibers of the vagus nerve in the airways.

How it works: Gefapixant blocks ATP-mediated activation of P2X3 receptors, which are thought to be responsible for chronic cough. It inhibits C-fiber activation in response to inflammation or chemical irritants.

Important Information: Treatment should be initiated and monitored by physicians experienced in managing patients with chronic cough disorders. Dose adjustment is needed in severe renal impairment (eGFR <30).

• Refractory chronic cough
• Unexplained chronic cough

Cough Therapy

P2X3 Receptor Antagonist

Gefapixant is a selective antagonist of the P2X3 receptor. P2X3-containing receptors belong to the family of purinergic receptors and are ATP-dependent ion channels, which are also located on sensory C-fibers of the vagus nerve in the airways. C-fibers are activated in response to inflammation or chemical irritants. Under inflammatory conditions, ATP is released by mucosal cells of the respiratory tract. The binding of extracellular ATP to P2X3 receptors is recognized by C-fibers as a damage signal and is perceived as a coughing stimulus, which in turn triggers a cough reflex.

Gefapixant blocks P2X3 receptors to inhibit ATP action, thereby reducing cough reflex and controlling chronic cough.

Adult Dose:

• One 45 mg tablet orally twice daily with or without food
• If a dose is missed, skip it and take the next dose at the regular time

Severe Renal Impairment (eGFR <30 mL/min/1.73m²):

• One 45 mg tablet once daily with or without food

Elderly: No dose adjustment required (higher risk of reduced renal function)

Children (under 18 years): Safety and efficacy not established

* Use as directed by the registered physician

Oral tablet. Can be taken with or without food. Swallow whole.

If you miss a dose, skip it and take the next dose at the regular time. Do not double the dose.

Very Common (>10%):

• Dysgeusia (taste disturbance)
• Ageusia (loss of taste)
• Hypogeusia (reduced taste)

Common (1-10%):

• Upper respiratory tract infections
• Decreased appetite
• Dizziness
• Nausea
• Diarrhea
• Dry mouth
• Hypersalivation
• Epigastric pain
• Dyspepsia

Occasional: Urinary stones, bladder stones, nephrolithiasis

Precautions:

• Use with caution in patients with known hypersensitivity to sulphonamides.
• Should not be used in patients with obstructive sleep apnea.
• May affect driving ability and use of machines (dizziness) - caution required.

Contraindications:

• Severe hypersensitivity reaction to Gefapixant or any of the ingredients

Drug Interactions:

• Omeprazole (proton pump inhibitor) had no clinically meaningful effect on pharmacokinetics.
• Potential for CYP inhibition or induction is low.
• No clinically dependent drug interactions have been identified.

Food Interactions: No interaction found/established.

Use in Pregnancy: Use during pregnancy and in women of childbearing potential who do not use contraception is not recommended.

Use in Lactation: It is not known whether gefapixant is present in human breast milk. Detected in milk in animal studies.

Pediatric Use: Safety and efficacy in patients below 18 years have not been established.

Geriatric Use: No dose adjustment due to age is required. However, older patients are more likely to have impaired renal function - caution required.

Renal Impairment: Severe impairment (eGFR <30): 45 mg once daily. Mild or moderate impairment: No dose adjustment required.

Hepatic Impairment: No data available for use in patients with hepatic impairment.

Overdose: Patient should be observed for adverse reactions and appropriate symptomatic treatment initiated. Gefapixant is partially removed by hemodialysis.

Storage: Store below 30°C in a cool and dry place. Keep away from light. Keep out of reach of children.

Gefapixant Citrate Tablet