Almitrine (Molecule of the Month for February 2021)
Almitrine is a respiratory stimulant. It enhances respiration by acting as an agonist of peripheral chemoreceptors located on the carotid bodies. The carotid body is located in the adventitia, in the bifurcation (fork) of the common carotid artery, which runs along both sides of the neck. The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of arterial oxygen, but also of carbon dioxide. It is also sensitive to changes in blood pH, and temperature.
As a result the drug increases arterial oxygen pressure while decreasing arterial carbon dioxide pressure in patients with chronic obstructive pulmonary disease. It may also prove useful in the treatment of nocturnal oxygen desaturation without impairing the quality of sleep.
A clinical trial began this week to test whether a drug called Almitrine can help people who are seriously ill with COVID-19 to recover from the disease.
The trial is a close collaboration between academic staff located across different departments at the University and NHS hospital consultants. The researchers include Professor Chris Schofield at the Department of Chemistry, Professor Peter Robbins and Professor Keith Dorrington at the Department of Physiology, Anatomy and Genetics, and Professor Najib Rahman at the Nuffield Department of Medicine. The trial, which is supported by a grant from the medical research charity LifeArc, commenced this week at the Royal Berkshire NHS Foundation Trust in Reading. Almitrine will be administered orally to patients over a seven-day period to determine whether it is effective in reducing the need for other forms of ventilatory support.
Patients suffering from COVID-19 pneumonia often develop very low levels of oxygen, called hypoxia, in the arterial blood supplying the body. The Oxford researchers hypothesise that the underlying problem is that the virus disrupts a normal process in the lungs called hypoxic pulmonary vasoconstriction, which diverts blood away from the diseased, non-functional parts of the lung and towards the parts of the lung that are still working properly. If the lungs are prevented from diverting blood to better-oxygenated lung segments, then this can cause the profound hypoxia from which patients with COVID-19 may die. Supportive therapy in hospitals aims to prevent this by using supplementary oxygen and ventilators to support breathing.
Almitrine bismesylate, a drug first developed in France, has been successful in treating acute respiratory distress syndrome by constricting the blood vessels in regions of the lung where the oxygen is low. Researchers say Almitrine could have the same effect in COVID-19 patients, with the potential to help restore the natural protective process in the lungs and increase oxygen levels in the arterial blood. The trial team hopes that administering this drug to COVID-19 patients will consequently reduce the amount of other respiratory support the patient needs.
Formal Chemical Name (IUPAC)
Update by Karl Harrison
(Molecule of the Month for February 2021 )
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