The initial months of the COVID-19 pandemic required a global effort to identify effective treatments. Clinical trials were quickly initiated to determine if powerful drugs, specifically steroids, could safely alter the course of severe COVID-19 infection. Clear guidance eventually emerged, confirming that a specific type of steroid is a beneficial intervention for patients experiencing the most severe effects of the virus. This established a standard of care for hospitalized patients with respiratory compromise.
Understanding Corticosteroids Versus Anabolic Steroids
The term “steroid” refers to a class of compounds that share a similar molecular structure, but they function very differently. The steroids effective against severe COVID-19 are corticosteroids, such as Dexamethasone, Hydrocortisone, or Prednisolone. These substances mimic cortisol, a hormone naturally produced by the adrenal glands, which helps regulate stress and inflammation. Corticosteroids are primarily used in medicine for their strong anti-inflammatory and immunosuppressive properties to treat conditions like asthma, allergies, and autoimmune disorders.
This class of medication is entirely distinct from anabolic steroids, which are often what the public imagines when hearing the word “steroid”. Anabolic steroids are synthetic versions of testosterone, and their primary function is to promote muscle growth and increase male characteristics. While anabolic steroids bind to androgen receptors, corticosteroids bind to glucocorticoid receptors. This difference leads to fundamentally different physiological effects, medical uses, and risk profiles.
How Steroids Counter the Effects of Severe COVID-19
Corticosteroids do not attack the SARS-CoV-2 virus directly; they address the body’s damaging overreaction to the infection. Severe COVID-19 can trigger a “cytokine storm,” an uncontrolled systemic inflammatory response. This storm involves the massive release of pro-inflammatory signaling molecules called cytokines, leading to widespread tissue damage. The lungs are particularly vulnerable to this excessive inflammation, which can progress rapidly to acute respiratory distress syndrome (ARDS).
Corticosteroids, specifically Dexamethasone, suppress this hyper-inflammatory cascade. They enter host cells and bind to glucocorticoid receptors, inhibiting the synthesis of multiple pro-inflammatory cytokines. This mechanism dampens inflammation in the lungs, reducing damage to the air sacs and improving oxygen exchange. Large-scale clinical evidence, such as the RECOVERY trial, confirmed that this anti-inflammatory action significantly reduces the 28-day mortality rate in the sickest patient groups.
Clinical Criteria for Treatment and Timing
The benefit of corticosteroids depends strongly on the severity of the illness and the timing of administration. Guidelines recommend reserving steroid therapy for patients with severe COVID-19 who require supplemental oxygen or mechanical ventilation. The powerful immune-suppressing effect is most beneficial during the hyper-inflammatory phase, which typically occurs more than seven days after symptom onset. For critically ill patients, Dexamethasone at 6 milligrams once daily for up to 10 days is the standard regimen.
Steroids are not recommended for patients with mild or early-stage COVID-19 who do not require oxygen support. In these cases, the immune-suppressing effect could hinder the body’s initial fight against the virus, increasing the risk of delayed viral clearance. Data showed the drug did not reduce mortality, and may even be harmful, in patients not receiving respiratory support. The goal of treatment is to modulate the host’s inflammatory response at the appropriate time, not to fight the virus directly. If Dexamethasone is unavailable, alternative corticosteroids like Prednisolone or Methylprednisolone can be substituted at equivalent doses.
Risks and Required Patient Monitoring
While corticosteroids save lives in severe cases, their use requires close patient monitoring due to adverse effects. A primary concern is the induction or worsening of hyperglycemia (high blood sugar), which is risky for patients with pre-existing diabetes. Steroids increase blood glucose levels by promoting liver glucose production and increasing insulin resistance. This requires vigilant monitoring, often necessitating the temporary introduction of insulin therapy even in non-diabetic patients.
Another risk is the potential for secondary infections due to the drug’s immunosuppressive nature. By dampening the immune system, corticosteroids can increase susceptibility to bacterial or fungal superinfections, such as pulmonary aspergillosis. Prolonged use has also been linked to conditions like mucormycosis, a severe fungal infection. Because of these risks, the dosage and duration of treatment are strictly limited. Clinicians must continually evaluate the balance between the drug’s life-saving benefit and the potential for harm.