Use of Drugs that Act on the Cytochrome P450 System in the Elderly

Abstract

Cabrera MAS, Dip RM, Furlan MO, Rodrigues SL. Use of drugs that act on the cytochrome p450 system in the elderly. Clinics. 2009;64(4):273-8. OBJECTIVES:The objective of this study was to analyze medications that act on the cytochrome P450 (CYP450) enzymatic system and are used daily by non-institutionalized elderly individuals. METHODS: A cross-sectional population-based study of elderly individuals (≥ 60 years old) was conducted. All continuously used medications with hepatic metabolism via CYP450 that are classified as substrates, inducers or inhibitors were considered. For the analysis, elderly individuals were stratified according to age groups, and hepatic metabolism activity due to daily alcohol consumption and smoking were considered. RESULTS: Elderly individuals (396 in total: 222 women and 174 men) between 60 and 95 years of age (mean: 72.1) were assessed. Use of drugs that act on CYP450 was identified in 61.6% of the subjects. Drug use was observed among 16.2% of the subjects: three drugs among 9.8% and four or more among 6.3% of the subjects. The metabolic activities of the drugs used were classified as substrates (58.8%), inhibitors (14.9%), and inducers (4.3%). The main drugs used were beta-blockers and statins (as substrates), proton pump inhibitors and fluoxetine (as inhibitors), and prednisone and carbamazepine (as inducers). CONCLUSIONS:The results demonstrate that the elderly use high levels of medications that act on CYP450, thereby increasing the risk of drug interactions in a group that is already vulnerable to adverse drug effects.

Inappropriate Prescribing Predicts Adverse Drug Events in Older Adults

“…Lack of efficacy can also be a potential outcome of drug-drug interactions, either through metabolic enzyme induction or inhibition of prodrugs, but these interactions are relatively rare in practice. 19, 20 The second category included the 4 MAI criteria centered on unwarranted medication use. These criteria were considered to confer secondary risk since they do not directly relate to ADEs.…”

Drugs with activity on the cytochrome P450 used by elderly at home

“…3 Estudo nacional realizado no Paraná com idosos não institucionalizados identificou que 61,4% dos idosos utilizavam medicamentos com atividade sobre CYP450. 15 A maior frequência detectada nessa investigação (90,5%) pode ser explicada pelo perfil dos pacientes, portadores de polipatologias, com alto índice de comorbidade de Charlson e predomínio de doenças cardiovasculares. Além disso, apresentam probabilidade de serem portadores de doenças crônicas complexas pois estavam internados em um hospital de referência.…”

“…Entender o efeito de cada fármaco sobre o CYP450 se torna importante para orientar a prescrição de medicamentos a pacientes idosos, visto que interações medicamentosas podem reduzir ou aumentar o efeito dos mesmos, causando reações adversas. 15 Dentre os fármacos utilizados, foram mais frequentes os que exercem atividade no CYP3A4 e CYP2D6. Esse achado está de acordo com a literatura, que apresenta estas duas isoenzimas do CYP450 como sendo as mais significativas na metabolização de medicamentos.…”

Pharmacokinetic Modifications and Drug-Drug Interactions in Clinical Monitoring of the Elderly: A Short Review

“…In geriatric patients, several reports have shown that some drugs are poorly metabolized while others are not, although sometimes drugs from both metabolizing groups are targets of the same CYP (Table 2), indicating the complexity of the whole process [3]. In any case, it is important to bear in mind that elderly patients have a high incidence of CYP-metabolized drug treatment, which may increment the possibility of drug interactions and ADRs [30].…”