Betamethasone: Mechanism of Action, Indications and Main Secondary Effects

The betamethasone is a drug of the corticosteroid group used in humans since the 1960s. Despite the development of other glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs), betamethasone is still used to treat several diseases because of its potency, effectiveness and security profile.

It has a potency 300 times higher than hydrocortisone, a reference drug in the group of corticosteroids. Betamethasone can be used orally, injected and topically both in the skin (creams) and in the eyes (eye drops), and even in the nose through a nasal spray.

Mechanism of action

Betamethasone is a potent drug with anti-inflammatory and immunosuppressive action with little mineralocorticoid action.

Its main mechanism of action is the activation of a group of proteins known as lipocortins, which in turn inhibit phospholipase A2, responsible for the synthesis of leukotrienes from arachidonic acid, thus blocking the inflammatory cascade.

On the other hand, betamethasone acts directly on leukocytes, which are white blood cells, inhibiting the release of a series of chemical mediators such as acid hydrolases and interleukins.

Consequences of the inhibition of leukocyte acid hydrolases

Leukocyte acid hydrolases are a potent chemical mediator that recruits white blood cells to the site of inflammation.

By blocking the release of this mediator, betamethasone prevents the accumulation of macrophages in the area and reduces the adhesion of leukocytes to the capillary wall while reducing the permeability of this, thus decreasing inflammation.

The goal is to prevent inflammatory cells from accumulating in the area, which will subsequently release more and more chemical mediators, increasing capillary permeability and attracting more cells, ultimately causing edema (fluid accumulation) and inflammation.

Consequences of interleukin inhibition

Inflammation is the product of a series of complex chemical interactions between cells and blood vessels.

These are communicated by very specific chemical mediators that"recruit"more inflammatory cells in the area of ​​inflammation and favor the permeability of the blood vessels, so that both the fluid and the cells and the chemical mediators themselves reach the affected area.

Of the wide variety of chemical messengers involved in this process, the main responsible for vascular permeability are histamine, interleukin 1 (IL-1), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-). alpha).

In this sense, betamethasone acts by inhibiting the secretion of these compounds by inflammatory cells, thereby reducing the ability of these cells to migrate to the area where inflammation occurs, as well as the extravasation or leakage of fluid into the compromised area.

Indications for the use of betamethasone

Betamethasone has a wide variety of medical indications: from the common inflammation of the skin to the treatment of serious autoimmune diseases such as systemic lupus erythematosus.

The dose, route of administration and duration of treatment will depend on each case in particular. Here is a summary of the most common indications:

For skin diseases

Betamethasone is indicated in the treatment of atopic dermatitis, dermatitis fungoides, pemphigus, eczema and psoriasis, among other conditions.

In these cases, a compound of betamethasone dipropionate or betamethasone benzoate cream is administered topically, placing a thin layer once or twice a day while massaging the affected area.

For eye diseases

The main indication of ophthalmic drops whose active ingredient is betamethasone is severe allergic conjunctivitis that does not respond to other treatments. However, the list of potential indications is long.

The eye drops of betamethasone have application in a wide range of diseases of the eye, such as uveitis, chorioretinitis, endophthalmitis, Graves' ophthalmopathy and keratitis, among others.

The treatment interval, its duration and combination with other drugs will depend on the clinical conditions of each patient. In all these cases the treatment is delicate and should be supervised by an ophthalmologist at all times.

For diseases of the upper respiratory tract

While there are many treatments available, betamethasone has a place in the management of chronic inflammatory conditions of the upper respiratory tract, such as turbinate hypertrophy, chronic allergic rhinosinusitis, seasonal rhinitis and in some cases small nasal polyps.

In these cases, the route of administration is usually a nasal spray that is applied using a pyramid scheme; that is to say, it is started 3 or 4 times a day for a week, then the dose is reduced to 2 times a day for 7 more days and thus it decreases successively until it reaches zero.

Treatment with betamethasone of upper respiratory diseases is always prolonged and should be supervised by a specialist in the area to detect the development of eventual complications.

For autoimmune-immunohematological diseases

The main indication for the use of steroids in general, and betamethasone in particular, is for the control of autoimmune and immunoreumatological diseases.

In general, the drug is administered orally in the treatment of diseases such as polymyositis, rheumatoid arthritis, systemic lupus erythematosus, exacerbations of multiple sclerosis, polyarteritis nodosa, mixed collagen disease, non-suppurative thyroiditis and vasculitis, to mention only the most common.

When oral treatment is not enough, betamethasone can be administered parenterally (injected), usually intramuscularly. This is the route of choice in certain pathologies, such as graft-versus-host disease.

Once again, betamethasone is a drug of delicate use that should only be administered under strict medical supervision. It is important never to self-medicate because of the risks that this implies for health due to inadequate control of the disease or side effects of the medication.

For adrenal insufficiency

Betamethasone can also be used in the treatment of adrenal insufficiency, which is when the adrenal gland does not produce enough hormones.

However, due to its poor mineralocorticoid effect, it must be combined with a drug from this group to provide complete treatment.

Other indications

In general, any acute or chronic inflammatory disorder where effective and immediate control of symptoms is required can be treated with betamethasone. Therefore, betamethasone is indicated in the crisis of bronchial asthma, anaphylactic shock and chronic bronchitis and urticaria.

Likewise, in cases where it is sought to prevent inflammation after the administration of a treatment aimed at destroying a tumor or parasite -chemotherapy, treatment of hydatid cysts, etc.- betamethasone can be used as prophylaxis in order to avoid secondary inflammation. to treatment even before it occurs.

Finally, betamethasone can be used for fetal lung maturation in those cases where there is a risk of premature labor.

The 2 main types of side effects of betamethasone

Betamethasone is a powerful drug and very effective in the treatment of the conditions for which it is indicated. However, it is not free of adverse effects, some mild and others more serious.

Basically there are two types of side effects: local and systemic.

1- Local side effects

When it is administered topically, especially on the skin and for a long time, cases of:

- Contact dermatitis.

- Hypertrichosis (increase in the amount of hair in the treated area).

- Folliculitis.

- Miliaria.

- Cutaneous atrophy.

- Dryness

- Hypopigmentation.

Since absorption from local administration sites is minimal, it is uncommon for cases of systemic adverse reactions to occur when the drug is administered locally, unlike when the route of administration is oral or parenteral.

2- Systemic side effects

In general, brief treatments of acute diseases -such as bronchial asthma, anaphylactic shock or urticaria- are not associated with severe or lasting side effects.

The most frequent in these situations is gastrointestinal intolerance, which is manifested by the onset of nausea and vomiting.

However, when the treatment is for a long time, more serious side effects may occur:

- Depression

- Arterial hypertension.

- Suprarrenal insufficiency.

- Appearance of petechiae (red spots on the skin).

- Tendency to the formation of bruises.

Likewise, in patients with a history of ulcero-peptic disease, there is a risk of upper gastrointestinal bleeding, while in those with sensitivity to the drug, allergic reactions may occur.

Betamethasone in children

In children the use of corticosteroids for a long time is contraindicated unless the benefits clearly outweigh the risks, given that their administration inhibits the formation of growth cartilage, negatively influencing the final size of the child.

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