Vitamina D Afeta Efetividade Dos Remédios

[quenca333 140]

Sun Exposure, Vitamin D Can Affect Breakdown of Medicines

by Walter Jessen

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Genetic variation has been though to be responsible for the differences between people to metabolize certain drugs. The results of a recent study from the Karolinska Institutet in Sweden suggest that it may be even more complicated. Swedish reserchers have found that the body’s ability to break down medicines may be closely related to sunlight exposure and vitamin D, and thus may vary with the seasons. The study, published in the journal Drug Metabolism & Disposition, offers a completely new model to explain individual differences in the effects of drugs [1].

Sunlight can influence the breakdown of medicines in the body

The cytochrome P450 enzyme superfamily (abbreviated as CYP) are the major enzymes involved in drug metabolism and bioactivation. Cytochrome P450, subfamily IIIA, polypeptide 4 (CYP3A4) is the primary CYP expressed in adult human liver. It is both continuously expressed as well as activated by a variety of clinically used drugs. CYP3A4 activity is known to show a significant variability not only between different people but also within the same person at different times. The reason for this variability is unknown.

The goal of the present study was to test the hypothesis that plasma concentrations of three immunosuppressant drugs — tacrolimus, sirolimus and cyclosporine — show seasonal variations associated with increased CYP34A4 enzyme via vitamin D. These drugs were used because they are dependent on the CYP3A4 metabolic pathway and most patients taking these drugs use them for long periods of time and require repeated concentration determinations.

The researchers reviewed almost 70,000 analyses from patients who had undergone regular monitoring of the levels of drugs in their blood. They found that samples collected during the summer (July-September) had significantly lower dose-corrected concentrations of tacrolimus and sirolimus compared to those collected during the winter (January – March). In contrast, no change was detected in cyclosporine concentrations.

A more detailed analysis found that the concentrations of tacrolimus and sirolimus vary throughout the year, closely reflecting the changes in the level of vitamin D in the body. The body depends on sunlight to form vitamin D. The highest levels of vitamin D in patients taking part in the study were reached when the levels of the drugs were lowest.

Although the results are correlative, not causal, scientists think the connection between sunlight, vitamin D and the bioavailability of sirolimus and tacrolimus arises from the activation by vitamin D of the liver detoxification system, specifically by increasing the amount CYP3A4. In turn, CYP3A4 is responsible for the breakdown of tacrolimus and sirolimus.

Jonatan Lindh at the Karolinska Institutet Department of Laboratory Medicine and lead author of the study said [2]:

If the breakdown capacity increases, then higher doses of a drug are normally required in order to achieve the same effect. More research will be needed to confirm the results, but CYP3A4 is considered to be the most important enzyme in drug turnover in the body, and the results may have significance for many drugs.

Just three years ago, we reported on the International Serious Adverse Events Consortium (SAEC), which announced plans to identify genetic markers that predicted drug-related serious adverse events. The results of the current study suggest that individual differences in the effects of drugs is even more intricate than just genetics alone.

fonte: http://www.highlighthealth.com/research/sun-exposure-vitamin-d-can-affect-breakdown-of-medicines/

[ImFool 80]

pra que serve essas sirolimus e tacrolimus?

[quenca333 140]

imunossupressores, mas eu não acho que esse efeito se traduz na interferência de apenas estes tipos de medicamentos

[Tycoon 102]

eu não acho que isso seja algo preocupante

melhor pegar seu solzinho e ter vitamina D suficiente do que ser deficiente nisso.

"Vitamin D deficiency is now recognized as an epidemic in the United States. A growing body of research indicates that vitamin D deficiency contributes to a broad spectrum of conditions such as high blood pressure, poor insulin sensitivity, inflammation, and other fundamental processes that underlie heart disease. Another health consequence that should be of concern to bodybuilders is that low vitamin D levels are associated with low testosterone."

fonte: http://www.musculardevelopment.com/articles/nutrition/2410-low-vitamin-d-level-lowers-testosterone-levels.html

http://www.mindandmuscle.net/articles/vitamin-d-testosterone/

[quenca333 140]

nem eu, mas quando estiver tomando remédios vou evitar tomar vitamina D, mesmo essa negócio dos remédios ainda ser uma coisa incerta.

Só quis deixar o alerta para se servisse para alguém, mas pelo menos por enquanto vitamina D é a "vitamina da vez" para quem treina

[Tycoon 102]

nem eu, mas quando estiver tomando remédios vou evitar tomar vitamina D, mesmo essa negócio dos remédios ainda ser uma coisa incerta.

Só quis deixar o alerta para se servisse para alguém, mas pelo menos por enquanto vitamina D é a "vitamina da vez" para quem treina

verdade...já deve fazer quase 2 meses que to suplementando com vitamina D 10.000ui/dia. Eu era deficiente com certeza, visto que na minha rotina diária, tirando no verão, praticamente não pego exposição a luz solar direta.

Ainda falta fazer os exames de sangue pra confirmar, mas eu tenho certeza que fez uma diferença positiva, me sinto melhor de maneira geral.

[quenca333 140]

eu tenho uma teoria para vitamina D:

1) A maioria das pessoas, principalmente que vivem em cidade grande, são deficientes.

2) A dose ótima é um pouco maior do que o mínimo recomendado.

O que acontece é que quando as pessoas começam a tomar doses mais altas, elas começam corrigindo a deficiência e por isso melhoram seu perfil hormonal com essas doses mais rapidamente, afinal essa vitamina é um hormônio também. Mas a partir desse ponto eu acredito que não deve ter benefício usar mais que 1.000-2.000 UI por dia. Não é nada científico, mas é geralmente assim que as coisas funcionam com as vitaminas.

[Tycoon 102]

eu concordo exatamente com o que vc disse quenca,

tanto que eu to dando esse período de "loading" na minha vitamina D, e após eu realizar os exames, se tiver tudo dentro do normal, vou manter em 5000ui/dia, que já é mais do que o necessário.

[R.Hellmann 60]

Tycoon já pensou em tomar a Vit D de outras formas, tipo ao invés de Tomar todo dia uma dose certa, megadosar um dia e aliviar nos outros?

[Tycoon 102]

Tycoon já pensou em tomar a Vit D de outras formas, tipo ao invés de Tomar todo dia uma dose certa, megadosar um dia e aliviar nos outros?

pelo fato da vt. D ser liposolúvel e ir se acumulando no organismo, eu acho que não faz diferença se o cara vai tomar 5.000ui por dia durante a semana ou 35.000ui de uma vez só. Inclusive quando eu sei que vou viajar, ou passar o fds fora até antecipo as doses.

Mas no geral eu sou bem metódico com isso, já to acostumado é automático, tomo junto com o multivitaminico sempre