[Peripheral neuropathy with hypervitaminosis B6 caused by self-medication]. / Neuropathie périphérique avec hypervitaminose B6 provoquée par l'automédication.

INTRODUCTION: Vitamin B6 is contained in a number of over-the-counter drugs and vitamin supplements. It may cause severe neurological troubles in case of overdosage. CASE REPORT: We report the case of a 92-year-old women with gait disorders. A diagnosis of peripheral neuropathy with both motor and sensitive deficits was established and investigated. Blood level of vitamin B6 was measured to investigate a potential deficiency. Unexpectedly, the results showed hypervitaminosis B6, which appears to be due to self-administration of an over-the-counter drug containing vitamin B6. Discontinuation of this drug was associated with decrease in vitamin B6 level as well as gait improvement. We also discuss the toxicity of vitamin B6. CONCLUSION: Hypervitaminosis B6 remains a possible cause of peripheral neuropathy and it may be caused by self-administration of over-the-counter vitamin-containing drugs.

Risks of the 'Sunshine pill' - a case of hypervitaminosis D.

Vitamin D is a fat-soluble vitamin essential for calcium homeostasis and bone health. Vitamin D toxicity or hypervitaminosis D is extremely rare. We describe the case of a 73-year-old man who presented with life-threatening hypervitaminosis D and hypercalcaemia resulting from self-medicated doses of vitamin D supplements. This case, alongside other global case reports, highlights the potential dangers of unlicensed vitamin D replacement. We discuss the evidence for vitamin D replacement and remind readers of the current guidance on daily intake and supplementation.

Effects of preventive versus "on-demand" nutritional support on paid labour productivity, physical exercise and performance status during PEG-interferon-containing treatment for hepatitis C.

BACKGROUND AND OBJECTIVE: Deterioration of nutritional status during PEG-interferon containing therapy for chronic hepatitis C can be ameliorated by preventive nutritional support. We aimed to explore whether such support also affects paid labour productivity, physical exercise and performance status. METHODS: In this prospective randomized controlled trial (J Hepatol 2012;57:1069-75), 53 patients with chronic hepatitis C had been allocated to "on demand" support (n=26: nutritional intervention if weight loss>5%) or preventive support (n=27: regular dietary advice plus energy- and protein-rich evening snack) during PEG-interferon-containing therapy. Paid labour productivity, physical exercise and performance status were evaluated at baseline, after 24 and (if applicable) after 48 weeks of treatment. RESULTS: At baseline, 46% of patients performed paid labour and 62% performed some kind of physical exercise. Furthermore, most patients were able to carry out normal activity with only minor symptoms of disease (mean Karnofsky performance score: 94). Decreases of paid labour productivity (-21% vs. -70%, P=0.003), physical exercise activity (-43% vs. -87%, P=0.005) and Karnofsky performance scores (-12% vs. -24%, P<0.001) were less in the preventive than in "on demand" group after 24 weeks of treatment. Effects of preventive nutritional support were even more pronounced after 48 weeks. CONCLUSIONS: Preventive nutritional support markedly ameliorates decreases of paid labour productivity, physical exercise and performance status during PEG-interferon-containing treatment for chronic hepatitis C.

Vitamin D3 quantification in a cod liver oil-based supplement.

A reliable, accurate and reproducible method to quantify vitamin D3 (Vit. D3) in oily dietary supplements was developed after three Vit. D3 intoxications were diagnosed as reasonably resulting from a dietary administration of a cod liver oil based supplement. Liquid chromatography coupled to mass spectrometry operating in atmospheric pressure chemical ionization conditions (LC-APCI) and by using a deuterium labelled internal standard resulted to be an effective technique to reach the analytical aim. Due to the complexity of the oily matrix, the new analytical approach required a solid phase extraction step prior to analysis. The amount of Vit. D3 declared on the label of the cod liver oil based supplement for each soft capsule is 1.5µg. Consequently, the method was developed to quantify Vit. D3 amounts in the range 1-5µg/mL. To improve reliability of obtained data, both MS and MS/MS acquisition methods were employed. The method was evaluated by measuring the characteristic parameters such as linearity, precision, accuracy and robustness and cross checked against a certified pharmaceutical preparation. The LC-APCI-MS and MS/MS methods were applied in order to assess the Vit. D3 content in the dietary supplements taken by the intoxicated patients, found about three order of magnitude higher than that declared. The Vit. D3 content of other batches of the same commercial product was found as declared.

Therapeutic effects of drug-nutrient interactions in the elderly.

The elderly are the major drug users both because they need specific prescription drugs for control of chronic diseases and because they make excessive use of over-the-counter (OTC) drugs. Therapeutic drugs that are required may be discontinued because the individuals suffer side effects or because the drug is ineffective. Adverse drug reactions in the elderly may result from drug overuse or misuse, slowed drug metabolism or elimination secondary to aging or to age-related chronic disease, intake of alcohol, food-drug incompatibilities, or nutrient-drug interactions. The timing of drug intake in relation to food intake is an important determinant of therapeutic efficacy in the elderly. Food-drug interactions in the gastrointestinal tract may reduce drug absorption. Enteral formula feeding may also interfere with drug absorption. Conversely, absorption of certain drugs (e.g., thiazides) may be promoted by meal-induced slowing of gastric emptying time. Therapeutic diet prescription can influence drug responses in the elderly because the protein composition of the diet influences the rate of drug metabolism. Nutrient depletion secondary to the effect of drugs may be recognized as an important and often avoidable type of adverse drug reaction.

The impact of antitumor therapy on nutrition.

The treatment of the cancer patient by surgery, chemotherapy or radiation therapy can impose significant nutritional disabilities on the host. The nutritional disabilities seen in the tumor-bearing host from antitumor therapy are produced by factors which either limit oral intake or cause malabsorption of nutrients. The host malnutrition caused as a consequence of surgery, chemotherapy or radiation therapy assumes even more importance when one realizes that many cancer patients are already debilitated from their disease.

Tumoricidal potential of nutritional manipulations.

Perturbations of specific nutrient availability is the basis of a large number of chemotherapeutic modalities used in cancer treatment. The creation of transient nutrient deprivation states by deficient diets (deficiency), nutrient destruction or displacement (depletion), the presence of antimetabolites or analogs (deficiency state), or combinations of the above has shown significant antitumor effect in several animal and human cancers. Pair-fed isocalonic diets deficient in micronutrients such as carbohydrates (with or without gluconeogenesis inhibition) or micronutrients such as zinc or pyridoxine have demonstrated antitumor potential. Amino acid depletion by enzymes such as L-asparaginase or L-glutaminase has become a popular modality for treatment of human leukemias. Purine and pyrimidine analogs or folate antimetabolites have been used successfully for several decades in the treatment of human tumors. Excess pyridoxine in tissue culture has demonstrated antineoplastic potential. Dietetic supplementation with naturally occurring sugars, sugar derivatives, or analogs has also demonstrated tumorotropic effects.

Effect of oral prophylactic broad spectrum nonabsorbable antibiotics on the gastrointestinal absorption of nutrients and methotrexate in small cell bronchogenic carcinoma patients.

Patients with small cell bronchogenic carcinoma, in a study utilizing laminar-air-flow-protected environments, oral prophylactic broad spectrum non-absorbable antibiotics (PNAA), and intensive combination chemotherapy, were examined to determine the effects of PNAA on serum biochemical values and on gastrointestinal absorption of both nutrients and methotrexate. With use of PNAA the following abnormalities were observed; serum carotene and folate decreased, D-xylose absorption was impaired, fat globules and muscle fibers were demonstrable in the stool, and the mean weight loss in 6 weeks was 10.2% as compared with 4.3% in patients not treated with antibiotics. Methotrexate absorption decreased from a mean of 69% prior to antibiotic use to 44% on PNAA. Thus, PNAA causes malabsorption of both nutrients and drugs. It appears unwise to treat patients on PNAA with oral antineoplastic drugs. Nutritional status must also be closely monitored and supplemental nutrition, either intravenously or with elemental diets, must be considered.