All about Antifungals

Molecules capable of selectively inhibiting the development of pathogenic fungi (or fungi).

What are antifungals

The group of antifungal (or antifungal) drugs includes all those molecules capable of selectively inhibiting the development of pathogenic fungi (or fungi).

For this reason they are used to treat mycoses, ie infections caused by fungi and yeasts that can proliferate in different areas of the body, for example between the toes or on the nails of the hand.

Some fungi (so-called dermatophytes) are for example particularly attracted to keratin contained in the hard and water-repellent tissues that form skin, nails and scalp and can cause skin mycoses, onychomycosis or mycosis of the scalp.

For this reason, antifungals can for example be used to treat ringworm, athlete’s foot (a mycosis so called because it often affects those who practice sports), candidiasis and some severe forms of dandruff.

However, mycoses are not diseases exclusively reserved for dermatology and can also affect other tissues and organs.

Systemic fungal infections can for example affect the lungs, or the brain; This is the case of fungal meningitis, in which a fungus manages to infect the membranes surrounding the brain and spinal cord.

The relevance of this pharmaceutical class is particularly topical in view of the alarming growth of fungal infections recorded in recent years.

This phenomenon is essentially due to the increased survival of patients suffering from immunodeficiency conditions (AIDS patients, subjects undergoing cancer therapies, transplant recipients undergoing anti-rejection therapies).

In fact, a compromised immune system, such as that of a person with AIDS or undergoing aggressive chemotherapy treatment, or who is taking drugs such as corticosteroids or immunosuppressants, is particularly exposed to the risk of fungal infections.

The increase in the incidence of mycoses mainly concerns infections caused by fungi that are not dangerous in themselves – often belonging to the normal microbial flora of the organism – which, however, become pathogenic if in the presence of an impairment of the immune defenses (therefore called opportunists).

In these cases, the availability of effective antifungal drugs is fundamental, as opportunistic mycoses tend to spread rapidly within the body affecting multiple organs (systemic mycoses), and are difficult to control.

Among the systemic mycoses most commonly associated with immunodepression are those caused by the fungi Candida albicans (systemic candidiasis) and Aspergillus fumigatus (pulmonary aspergillosis).

How they work

Like antibiotics, antifungals also work by selectively damaging the cellular structures or processes of the pathogen.

The possible results of their action are two. In the case of some antifungals the cells of the fungus die; For example, the medicine can kill them by triggering the leakage of cellular contents.

Others, such as undecylenic acid and sertaconazole, can prevent the fungus cells from growing or reproducing.

In the case of fungal infections, however, the greatest difficulty encountered in the development of drugs that are both effective and specific is represented by the fact that, unlike bacteria, fungi are made up of cells similar to those of animal organisms (eukaryotic cells).

The presence in fungal cells of structural and functional characteristics similar to those of human cells makes it more difficult to find molecules that are toxic to the cells of the infectious agent and not to those of the infected organism.

What are they?

Currently, there are several groups of antifungal drugs, classified according to chemical structure, mechanism of action or clinical use.

In the latter classification they are differentiated according to whether they are used locally in the treatment of superficial (skin) mycoses or systemically in the treatment of mycoses of internal organs.

Also among antifungals, as between antibiotics and antivirals, there are also molecules of natural origin, such as those produced by bacteria of the genus Streptomyces and fungi of the genus Penicillium (the best known are amphotericin B, griseofulvin, nystatin) and non-natural synthetic molecules, such as azoles (so called from a component of their chemical structure that defines the ending of their names: clotrimazole, bifonazole, ketoconazole, miconazole).

Among the most used antifungals are the aforementioned clotrimazole, miconazole, ketoconazole and amphotericin B, econazole, fluconazole and terbinafine, which depending on the case can be prescribed alone or in combination.

More specifically, systemic infections are generally treated with amphotericin B (or its lipid formulations), azole derivatives, flucytosine and echinocandins. Given the possible toxicity of amphotericin, the latter, together with less toxic triazoles, often take its place in the therapy of many invasive mycoses.

Among the possible formulations that can be purchased in pharmacies – some of which can be purchased without a prescription, such as supplements – are included both topical products (to be applied directly to the skin, nails or hair, for example creams, sprays and shampoos for hair hygiene), and oral formulations (capsules, pills or solutions), products to be inserted into the vagina to treat infections such as vaginal candidiasis and solutions to be injected into a vein.

The most suitable solution depends on the type of mycosis you are dealing with. The best way not to make mistakes is to follow the instructions provided by your doctor and pharmacist.

Side effects of antifungals

The possible side effects of antifungal treatments vary depending on the type of product and the active ingredient used. In particular, let’s see what are the side effects that can be caused by topical and oral antifungals:

Topical antifungals Itching and a mild burning sensation and redness that require you to stop treatment and seek medical attention
Oral antifungals Feeling generally unwell, stomach pain, diarrhoea, flatulenceheadacheindigestion, skin rash

Generally these disorders are mild and short-lived, but there are also antifungals that can trigger severe allergic reactions (with swelling of the face, neck or tongue and difficulty breathing) or an intense skin reaction that requires immediate medical attention.

It is also good to remember that antifungals can affect the results of laboratory tests, for example by altering cholesterol levels.

As for the liver, fortunately liver damage is a rare side effect of oral antifungals.

However, it is good to stop taking the medications and contact your doctor if you lose your appetite, vomiting, feeling sick for a long time, jaundice, dark urine, pale stools or unusual tiredness or weakness.

Finally, the administration of antifungals into a vein – in particular amphotericin B – can cause loss of appetite, feeling sick, vomiting, diarrhea, upper stomach pain, fever, chills, muscle and joint pain, anemia and skin rash, alteration of blood levels of electrolytes and, more rarely, irregularities of the heartbeat, changes in blood pressure and alterations in the functioning of the liver.

Warnings and contraindications

When relying on topical antifungals (for example in the form of cream) it is good to avoid contact with the eyes and mucous membranes (for example the inside of the mouth or nose), unless they are specifically designed for administration at the level of these tissues.

Furthermore, we must not forget that like many other drugs, antifungals can also have contraindications.

First of all it is important to remember that they may not be suitable for children. Also in this case it is good not to improvise and to rely on the advice received from the pediatrician and on the indications given in the package insert of the individual product.

In addition, small amounts of some drugs can pass into breast milk and then to the baby who feeds on them. For this reason, even women who are breastfeeding can take antifungals only after making sure that they are not contraindicated.

In many cases, pregnancy could also be included among the contraindications, but there are situations in which a pregnant woman finds herself struggling with a vaginal candida; In these cases, your doctor may give the green light to the use of antifungal creams or other products for vaginal use.Also before taking an antifungal medication it is important to take into account any health problems you suffer from (including allergies) and other medications taken.

In particular, some antifungals to be taken orally may be contraindicated if you suffer from heart, liver or kidney problems, and in some circumstances may induce hypoglycemic crises in those suffering from diabetes. For this reason, before taking them, it is good to consult with your doctor.

Other formulations, such as antifungal creams to be applied to the genitals or products for vaginal use, could damage condoms and diaphragms, reducing their contraceptive effectiveness during any sexual intercourse.

Some active ingredients can interfere with hormonal contraceptives based on estrogens and progestogens. As a result, their use could cause unexpected bleeding; In general, contraceptive efficacy does not decrease, but in case of doubt it is good to seek advice from your doctor.

In addition, all oral antifungals interact with estrogens, and some active ingredients may interfere with benzodiazepine metabolism, tricyclic antidepressants, cyclosporine and tacrolimus, cimetidine, hydrochlorothiazide, phenytoin, theophylline, zidovudine and the antibiotic rifampicin.

As far as diet is concerned, it seems that in most cases neither specific foods nor moderate alcohol consumption interfere with the action of these drugs.

Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.

The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.

Leave a Reply

Your email address will not be published. Required fields are marked *