Chlorpheniramine nasal spray alleviates long COVID symptoms

Inhaled chlorpheniramine maleate appears to reduce the risk of prolonged post-COVID symptoms, according to a study presented at ERS Congress 2023.

Safety check data from two randomized controlled trials—ACCROS I and III, with the prevalent omicron variants being 23A and 22F—showed that the prevalence of long COVID symptoms was significantly lower among patients who received 10-day treatment with inhaled chlorpheniramine at a dose of either 1% or 0.4% than among those who received placebo (ACCROS I: p<0.05 for all comparisons; ACCROS III: p<0.01 for all comparisons). [ERS 2023, abstract 3423]

ACCROS I

Between 5 and 16 months after participation in ACCROS I, there were four, nine, and 13 patients in the placebo group who reported experiencing fatigue, headache, and concentration problems, respectively. In the chlorpheniramine 1% group, on the other hand, only one patient reported headaches, and none had fatigue and concentration problems.

Moreover, 25 patients in the placebo group reported persistence of composite symptoms and impacted activities of daily living (ADL), whereas only one patient in the chlorpheniramine 1% group did so. Eleven patients in the placebo group sought medical attention for their symptoms.

In total, 56 patients in the chlorpheniramine group and 46 patients in the placebo group in ACCROS I responded to safety phone call checks involving a 17-question survey of symptoms during the follow-up.

ACCROS III

In ACCROS III, more placebo-treated than chlorpheniramine 0.4%-treated patients reported having fatigue (13 vs 0), headaches (28 vs 0), concentration problems (9 vs 0), anosmia/ageusia (7 vs 0), and joint muscle pain (3 vs 0) between 3 and 9 months after study participation.

Additionally, in the placebo group, 60 patients reported persistence of composite symptoms, 13 had impacted ADL, and 37 sought medical attention for their symptoms. On the other hand, none of the patients who received chlorpheniramine did.

The follow-up safety check included 83 patients in the chlorpheniramine group and 74 patients in the placebo group.

Anti-inflammatory and antiviral properties

In both ACCROS I and III trials, chlorpheniramine was associated with shorter clinical recovery time (defined as the change from baseline to day 7 in COVID-19 symptoms reported as the percent change in the daily symptoms score [DSS] and the severity of the disease symptoms using a visual analogue scale [VAS]) compared with placebo (1%: Δ%DSS –18.8 percent, Δ%VAS –8.6 percent; 0.04%: Δ%DSS –11.7 percent, Δ%VAS –8.2 percent).

This subsequent post-trial follow-up highlights the potential of inhaled chlorpheniramine in preventing or reducing the occurrence of long COVID symptoms, according to lead study author Dr Franck Rahaghi of Cleveland Clinic Florida in Weston, Florida, US.

“The antiviral and anti-inflammatory effect of inhaled chlorpheniramine can explain the significant impact in reducing time to clinical recovery in the acute illness,” Rahaghi said, adding that the drug may have better impact in terms of reducing long COVID symptoms. “This reformulated treatment could become a cornerstone intervention in addressing the dreaded issue of long COVID.”