Although no published data exist on the use of bitolterol by mouth or inhaler during lactation, data from the related drug, terbutaline, indicate that very little is expected to be excreted into breastmilk.[1] The authors of several reviews and an expert panel agree that use of inhaled bronchodilators is acceptable during breastfeeding because of the low bioavailability and maternal serum levels after use.[2][3][4][5][6]

The recent pandemic Coronavirus disease-19 outbreak had traumatized global countries since its origin in late December 2019. Though the virus originated in China, it has spread rapidly across the world due its firmly established community transmission. To successfully tackle the spread and further infection, there needs a clear multidimensional understanding of the molecular mechanisms. Henceforth, 942 viral genome sequences were analysed to predict the core genomes crucial in virus life cycle. Additionally, 35 small interfering RNA transcripts were predicted that can target specifically the viral core proteins and reduce pathogenesis. The crystal structure of Covid-19 main protease-6LU7 was chosen as an attractive target due to the factors that there were fewer mutations and whose structure had significant identity to the annotated protein sequence of the core genome. Drug repurposing of both recruiting and non recruiting drugs was carried out through molecular docking procedures to recognize bitolterol as a good inhibitor of Covid-19 protease. The study was extended further to screen antiviral phytocompounds through quantitative structure activity relationship and molecular docking to identify davidigenin, from licorice as the best novel lead with good interactions and binding energy. The docking of the best compounds in all three categories was validated with molecular dynamics simulations which implied stable binding of the drug and lead molecule. Though the studies need clinical evaluations, the results are suggestive of curbing the pandemic.

The beta-2 adrenergic agonists are a large group of drugs that mimic the actions of naturally occurring catecholamines such as norepinephrine, epinephrine and dopamine. Direct agonists directly interact with the adrenergic receptors, whereas indirect agonists typically stimulate the release of endogenous catecholamines. The beta-2 adrenergic agonists act mainly on the smooth muscle of the vasculature, bronchial tree, intestines and uterus. These agents also act on the liver stimulating glycogenolysis and release of glucose from the liver and muscle (particularly if used in high doses). The beta-2 adrenergic agonists are used largely as bronchodilators in the management of asthma, both in control of acute symptomatic attacks as well as chronic, long term prevention and management. These agents are some of the most commonly prescribed drugs for asthma and are widely used and proven to be well tolerated and safe. The use of beta adrenergic agonists in asthma has not been associated with elevations in serum aminotransferase or alkaline phosphatase levels or in causing clinically apparent liver disease. When given in large doses or after intentional overdose, beta adrenergic agonists can cause liver injury. Most case reports of liver damage from these agents have been associated with their use in control of premature labor (for their effects on relaxation of uterine smooth muscle). The liver injury typically arises within a few days of starting high dose intravenous beta adrenergic agonists, is usually asymptomatic, not associated with jaundice, and rapidly reversed once the medication is stopped. Commonly used beta adrenergic drugs include albuterol, bitolterol, metaproterenol, pirbuterol, salmeterol and terbutaline. These agents share structural similarity and are discussed together.

The Food and Drug Administration (FDA) is confirming the effective date of April 23, 2007, for the direct final rule that appeared in the Federal Register of December 7, 2006 (71 FR 70870). The direct final rule amends the regulation to remove beclomethasone, dexamethasone, fluticasone, bitolterol, salmeterol, ergotamine tartrate, and ipratropium bromide, used in oral pressurized metered-dose inhalers, from the list of essential uses of ozone-depleting substances. None of these products is currently being marketed. This document confirms the effective date of the direct final rule.

Patients with reversible bronchospasm benefit from the use of inhaled beta-adrenergic agents. In this retrospective study of 24 older patients with a variety of conditions associated with reversible bronchospasm--asthma, asthma with emphysema, chronic bronchitis, and asthmatic bronchitis--symptomatic improvement was noted after treatment with inhaled bitolterol mesylate. Symptoms resolved or improved after 1 month in 93.8% (15/16) of patients using a metered-dose inhaler and in 75% (6/8) of those using a hand-held nebulizer. Sixteen additional patients were randomly selected to undergo pulmonary function tests after receiving two to three puffs of bitolterol from a metered-dose inhaler. FEV1 improved by 10.9%, FVC by 12.1%, and FEF25%-75% by 34.4% after administration of bitolterol. No adverse events were noted in any patients in either group. The results of this retrospective study suggest that bitolterol is an effective and safe treatment in patients with conditions associated with reversible bronchospasm.

This open-label, placebo-controlled study was undertaken to assess the safety and effectiveness of bitolterol mesylate in pediatric asthma patients. Bitolterol mesylate was administered in increasing doses of 0.5 to 3.5 mg by continuous-flow nebulization on separate days to children 4 to 12 years of age. Pulmonary function tests and vital signs were measured before and for up to eight hours after each treatment. Bronchodilation was defined as a > or = 15% increase in FEV1 over baseline. Onset, magnitude, and duration of bronchodilation all showed general dose-related improvements. Onset of bronchodilation occurred within five minutes in 66% to 82% of all treatments. The mean maximum percent increase in FEV1 ranged from 35% to 52% for all doses. Median durations of bronchodilation in responding patients ranged from four and one tenth to more than eight hours. Bitolterol was well-tolerated with all adverse effects being mild to moderate in severity and transient in nature. Although the incidence of cough, increased pulse rate, and tremor were relatively low, they did increase slightly with the 2.5- and 3.5-mg doses. No significant clinical laboratory or electrocardiographic findings were noted. We conclude that doses of 1.0 and 1.5 mg bitolterol mesylate administered by continuous-flow nebulization are safe, effective, and well-tolerated for the treatment of asthma in pediatric patients.

Salmeterol (Serevent) is an inhaled beta 2-receptor agonist with more than twelve hours' effect duration compared with 4-6 hours for the more short-acting substances bitolterol, fenoterol, salbutamol, and terbutaline. Salmeterol has been studied in several large-scale double-blind multicenter studies with up to one year's duration. More than 6,000 asthmatics have been treated with salmeterol during these controlled studies. All studies show salmeterol to have a significantly better and well-maintained bronchodilating effect with better asthma control, fewer asthma exacerbations, and a decreased need for rescue albuterol inhalations used on demand compared to the treatments in the control groups (200-400 micrograms albuterol q.i.d., inhaled albuterol given only p.r.n., terbutaline given regularly, or individually titrated slow-release theophylline). Salmeterol should be given b.i.d. and in combination with inhaled corticosteroids. Salmeterol seems especially effective in patients with nocturnal symptoms, exercise induced asthma, and in patients sensitive to inhaled irritants such as cold air. The patients should always have short-acting inhaled beta 2-agonists available for break-through attacks. Inhaled salmeterol in combination with inhaled steroids seems to give the best maintenance asthma control available by inhalation today.

The hypoxic effects of salbutamol 200 micrograms (CAS 18559-94-9) and bitolterol mesilate 740 micrograms (Biterol, CAS 30392-41-7), both administered by pressurized aerosol, were assessed by transcutaneous pO2 monitoring in 18 asthmatic subjects and in 12 normal volunteers. Unlike the latter, the asthmatics showed a highly significant difference in ptcO2 time course after the two drugs. After bitolterol mesylate the decrease in ptcO2 was much more gradual and the maximal decrease showed a 10-min time lag vs. salbutamol, which may partly explain the well known chronotropic effect of bitolterol. The clinical importance of the beta 2-induced hypoxemia may be related more to the dynamics of the ptcO2 decrease than to its absolute magnitude, which is usually fairly moderate.