Minoxidil against baldness divides specialists; understand – 03/04/2023 – Equilibrium

Developed in the 1970s to treat high blood pressure, minoxidil is a medication that since the 80s has also been used in lotion form to treat androgenetic alopecia, better known as baldness. But recently, its use for hair growth has become controversial, motivated mainly by a report published in August 2022 in the newspaper “The New York Times” which highlighted the prescription of low-dose pills by American dermatologists. Currently, monitoring platforms such as Google Trends also identify an increase in searches about the drug.

The discussion involves physicians who advocate the controlled use of oral minoxidil at low doses and also those who contraindicate it because of its possible side effects. The popularization of the medicine on social networks, where its qualities are advertised without medical criteria and often with inappropriate dosages, increased the temperature of the debate.

The SBTri (Brazilian Society of Tricology), which brings together specialists from different areas of medicine, contraindicated any type of use of oral minoxidil for baldness in an official statement released in September.

The SBD (Brazilian Society of Dermatology), on the other hand, defended that the oral medication can indeed “be indicated in selected patients with alopecia”. The entity also said that “its judicious use, isolated or associated with other approaches, occurs by medical indication”, in a note published in October.

The two entities, however, agree on the risks of self-medication and the importance of medical monitoring for the treatment, since minoxidil is a medicine and, as such, can have side effects.

“We are against the indiscriminate use of minoxidil, buying it at the pharmacy without follow-up, buying it because you saw it on Instagram, without guidance. This we are super against, because there are side effects and you need to have a doctor at your side”, says physician Fabiane Mulinari Brenner , coordinator of the hair department at SBD.

Dermatologist Beni Grinblat, from Hospital Israelita Albert Einstein, points out that the use of oral minoxidil to treat baldness is widespread among Brazilian dermatologists.

“From a few years ago, studies began to appear on the use of minoxidil orally and then we saw that, with low dosages, it did not have the effect of lowering blood pressure, but maintained the beneficial effect in the treatment of baldness. I often prescribe for my patients,” says Grimblat.

A researcher at Unesp (São Paulo State University), physician Paulo Müller Ramos has been studying the effects of oral minoxidil in the treatment of baldness since 2016. He claims that the drug is prescribed especially for cases of androgenetic alopecia. But the medicine is also used as an adjunct in the treatment of hair loss caused by other factors, such as Covid-19 or invasive surgeries.

“A patient with hair loss caused by anemia or thyroid disorders, for example, could even use it as an adjunct. But, in some cases, such as hair loss due to Covid-19, this fall is usually reversed on its own, and there is no need for medication”, says Müller.

However, the prescription encounters strong resistance from some professionals, who highlight the possible side effects of the drug. This is the case of doctor Luciano Barsanti, president of SBTri, who published a note warning that the drug is not endorsed by Anvisa (National Health Surveillance Agency) in the treatment of baldness.

“These recent reports, like the New York Times report, minimize the serious and common adverse reactions of this oral drug, because it is an extremely potent hypotensive. This drug has adverse effects very often, because each individual has a different sensitivity to a drug”, points out Barsanti.

Loniten, Pfizer’s minoxidil, marketed in Brazil until 2010 and used to treat hypertension, was sold in 10 mg tablets and, according to Anvisa, is not indicated for the treatment of alopecia. The doses indicated by dermatologists for the treatment of baldness are currently made in compounding pharmacies and vary from 0.25mg to 5mg daily.

Scientific evidence and risks

Side effects of minoxidil are also reflected in the heart, since the drug promotes the dilation of blood vessels. The most serious are tachycardia, which is an increase in heart rate, and pericarditis, an inflammation of the membrane that surrounds the organ.

The most common reaction, however, is hypertrichosis, the scientific name for the exaggerated growth of hair all over the body: about 10% to 15% of patients who use minoxidil orally report this symptom. Another frequent reaction is swelling in the legs or face.

Luciano Barsanti, from SBTri, reports that most patients who come to his office have side effects.

“In the patients I see, 90% of those who have been taking minoxidil have adverse effects. The other 10% report no side effects, but many don’t necessarily relate [o que estão sentindo] with the medicine”, he says.

In a note, the SBTri advises users with alopecia to look for “doctors and trichologists who use non-invasive methods for the treatment”, and cites therapies such as electrostimulation and low-length laser.

Physician Fabiane Brenner, from SBD, points out that in-office therapies do not have such robust scientific evidence, and recalls that genetic baldness is a chronic disease that depends on continuous treatment.

“The baldness treatment guide is mainly based on minoxidil, especially for topical use, hair transplantation and hormone treatment. That’s what evidence-based medicine has. they should be treatments of exclusion, they should be the last alternative”, he explains.

Dermatologist Beni Grinblat also evaluates that, even with the possible side effects, the medicine is safe and can be a good alternative for patients with baldness.

“We have to guide the population that he [minoxidil] it is a treatment option, but of course always with a correct diagnosis, with medical follow-up, and then an evaluation of topical or oral use. We can never encourage self-medication”, adds Grimblat.

How does minoxidil work

Although studies have analyzed the action of minoxidil in the treatment of baldness since the 1980s, it is still unclear how the drug promotes hair growth.

Initially, scientific research pointed to the vasodilation promoted by the drug as its main mechanism of action. With increased circulation in the blood vessels of the scalp, the hair follicles, which are the structures where hair is born, would receive more nutrients, which would encourage their growth.

However, recent studies suggest that minoxidil has a direct action on the follicle, and that vasodilation is not the most important feature of the drug in the treatment of baldness.

“Nowadays, we do not believe that this is the main mechanism. What we observe is that there is a biochemical modification in the follicle that causes the hair to grow longer and become thicker with the use of the medicine”, says Brenner, from SBD.

Another effect of the drug on the scalp is the prolongation of the active phase of the hair follicle. With age, the hair growth phase becomes shorter. The use of minoxidil prolongs the period in which the follicle is active.