1500 administered four times every 12 h via umbilical catheter in 17 neonates with MAS [88]. Blood gases, X-ray, incidence of pneumothorax or pneumomediastinum, requirements for mechanical ventilation and mortality were comparable in the hydrocortisone-treated vs. placebo-administered group. However, longer period to wean to room air and remaining clinical signs of respiratory distress were observed in the treated group than in controls [88]. We may speculate that no benefit of the treatment may be caused by low dose or by late treatment, respectively, since the first dose of hydrocortisone was administered at about 5 h of age [88] when severe respiratory distress and inflammation have already been developed. No effect of hydrocortisone on meconium-induced lung edema in the study by Frantz et al. [25] may be explained by fluid retention in the lungs or delayed reabsorption of the fluid due to mineralocorticoid action of hydrocortisone. In addition, the anti-inflammatory potential of hydrocortisone is several times weaker than that of other GCs. Prednisolone is a GC drug with predominant glucocor- ticoid and low mineralocorticoid activity. Thanks to its strong anti-inflammatory and immunosuppressive action, it is used for the treatment of a wide range of inflammatory and auto-immune disorders, such as bronchial asthma, rheumatoid arthritis, ulcerative colitis, etc. In the study by Kirimi et al. [39], the intravenous administration of prednisolone at standard (2 mg/kg) and high (30 mg/kg) doses immediately after meconium instillation improved gas exchange and increased the frequency of breathing in meconium-instilled puppies in comparison with the non-treated group. In addition, high- dose prednisolone showed a more obvious improvement in lung histology compared to the standard dose, without hyperglycaemia or hypertension as side effects. However, high-dose prednisolone significantly increased the plasma levels of malonyldialdehyde, product of lipid peroxidation, compared to standard-dose group and controls at 20 h after meconium aspiration. It may suggest a paradoxically lower effectivity of high-dose vs. standard-dose prednisolone in the reduction of oxidation stress resulting from inflamma- tion or even the potentiation of oxidation stress by a mega- dose of prednisolone [39]. Nevertheless, the value of this information is limited by the small number of animals included in the treated groups (n =3 each). Methylprednisolone, a methylated derivative of prednis- olone, has similar properties and use as prednisolone. Since it may reach higher concentrations in the lungs than prednisolone due to a higher distribution volume, slower elimination and higher accumulation in the alveolar epithelium, it is used also for the short-term treatment of bronchial inflammation or acute bronchitis. Soukka et al. [66] found that, in 10-week-old pigs with MAS, pretreatment with methylprednisolone (30 mg/kg, i. Eur J Pediatr (2011) 170:1495–1505 v.) 30 min before the instillation of meconium tended to prevent an early (0–1 h) increase in pulmonary artery pressure and significantly inhibited the second-phase (1– 6 h) progressive rise in pulmonary artery pressure and pulmonary vascular resistance, decreased venous admixture and formation of lung edema and improved oxygenation [66]. In another study by Soukka et al. [67], premedication with methylprednisolone decreased the level of endothelin (ET)-1 and increased the level of atrial natriuretic peptide (ANP). The modulation of the ratio ET-1/ANP for ANP diminished pulmonary hypertension and indicated the protective effect of GCs on the endothelium-mediated regulation of the pulmonary vascular tone [67]. Thus, premedication with GCs before the labour might be beneficial in the case of verified massive meconium staining of the amniotic fluid and prenatal meconium aspiration to reduce remodelling of the pulmonary vascular lining and lung inflammation. However, up to this time, no clinical study was performed to evaluate the possible benefits of prenatal GCs delivery in MAS. Postnatally, methylprednisolone has been recently used in two trials carried out in India [4, 77, 78]. Methylpred- nisolone administered for a period of 7 days starting after 24 h of age in 34 newborns with MAS shortened the period of oxygen delivery and duration of hospital stay and improved the radiological clearance of the lungs, while no serious adverse effects including sepsis were observed [4]. In the study by Tripathi and co-workers [77, 78], methylprednisolone was given in 17 newborns with MAS at a dose of 0.5 mg/kg/day, i.v., in two divided doses every 12 h for 7 days. Similarly to the study by Basu et al. [4], methylprednisolone shortened the duration of stay, oxygen dependence and X-ray of the lungs, decreased the levels of TNFα in tracheal aspirate and did not increase the incidence of sepsis. Dexamethasone is a synthetic GC with potent anti- inflammatory and immunosuppressive action. It is >30 times stronger than hydrocortisone and about five times stronger than prednisone. Dexamethasone is also used for diagnostic procedures (to suppress the natural pituitary– adrenal axis) in obstetrics to promote the maturation of foetal lungs as well as in a wide spectrum of endocrine, oncological and other diseases. The first successful use of dexamethasone in MAS has been referred to in the 1990s, when it improved pulmonary ventilation and facilitated weaning from the ventilator in several newborns with severe MAS [86]. Later, numerous experimental and clinical studies evaluated the efficacy and management of dexamethasone administration in the con- ditions of MAS. Commonly, dexamethasone at a dose of 0.5 mg/kg body weight has been used. However, the timing of dexamethasone delivery appears to be critical for the effectiveness of treatment. In