There is concern that P-glycoprotein mediated efflux contributes to steroid resistance. Therefore, this study examined bidirectional corticosteroid transport and induction capabilities for P-glycoprotein (P-gp) to understand which of the systemic and inhaled corticosteroids interacted with P-gp to the greatest extent. Hydrocortisone, prednisolone, prednisone, methylprednisolone, and dexamethasone represented systemically active drugs, while fluticasone propionate, beclomethasone dipropionate, ciclesonide and budesonide represented inhaled corticosteroids. Aldosterone and fludrocortisone represented mineralocorticoids. All drugs were detected using individually optimised HPLC protocols. Transport studies were conducted through Caco-2 monolayers. Hydrocortisone and aldosterone had efflux ratios below , while prednisone showed a P-gp mediated efflux ratio of only compared to its active drug, prednisolone, with an efflux ratio of . Dexamethasone and beclomethasone had efflux ratios of and respectively, while this increased to for methylprednisolone. Fluticasone showed an efflux ratio of . Protein expression studies suggested that all of the inhaled corticosteroids were able to induce P-gp expression, from to 2 times control levels. Most of the systemic corticosteroids had higher passive permeability (>20×10(-6) cm/s) compared to the inhaled corticosteroids (>5×10(-6) cm/s), except for budesonide, with permeability similar to the systemic corticosteroids. Inhaled corticosteroids are not transported by P-gp to the same extent as systemic corticosteroids. However, they are able to induce P-gp production. Thus, inhaled corticosteroids may have greater interactions with other P-gp substrates, but P-gp itself is less likely to influence resistance to the drugs.
Inhaled corticosteroids are the most effective medicine to treat persistent asthma. Inhaled corticosteroids are asthma controller medicines. Asthma symptoms happen less often when an inhaled corticosteroid is used every day. When used every day, these medicines make the breathing tubes less sensitive by blocking the inflammation that leads to asthma symptoms.
Using a controller medicine reduces the need for rescue medicines and lowers the chance of needing to go to the emergency room for an asthma attack.
Because the main problem in asthma is long-term inflammation in the lungs, corticosteroids are often used to treat asthma. Corticosteroids help to reduce and prevent the swelling and excess mucus in the airway caused by inflammation.
For most people with asthma, corticosteroids are the single most effective medicine because they break the inflammation cycle and reduce the likelihood of future asthma flare-ups.
Inhaled corticosteroids are not like anabolic steroids. Although they have a similar name, they are very different from the anabolic steroids that are abused by some athletes. Also, it is important to know that concerns about using oral corticosteroids do not apply because inhaled corticosteroids are not absorbed into the body to any large extent .
A small number of individuals experience some local side effects, such as a yeast infection (white spots) of the mouth, tongue or throat and occasional hoarseness. Side effects can be avoided by rinsing the mouth after each treatment and using a spacer with a metered dose inhaler .