Slimming using magistral formulas: what are the risks?

Abstract

Introduction Magistral formulas (MF) are prepared by the pharmacist for a given patient according to a prescription and following technical and scientific compounding standards. MF are often used in weight loss regimens and contain blends of drugs (D) and plant (P) extracts. Associations potentiate interactions and related adverse effects, compromising effectiveness and risking the patient’s health [1,2]. Thus, the purpose of this work is to give an overview of MF intended for slimming, prescribed by doctors, in a perspective of efficacy and safety. Materials and methods Slimming MF (prescribed to overweight women, as hard gelatine capsules, once or twice daily) were obtained in pharmacies and analysed in terms of labelled drug/bioactive composition and dosage, therapeutic indication/claim, recommended daily dose (RDD), side effects/interactions and contraindications. Written consent for data use was obtained. Results MF did not contain unlawful ingredients [3]. Actives were used mostly in sub therapeutic doses (Table 1). Weight loss is a result of (a) side effect of D-III/IV (off-label use), (b) water loss due to therapeutic action (D-I/IX and P-V/VII/VIII), or (c) claimed appetite reduction (P-VI/X/XI). Table 1. MF labels composition and dose (mg). Active ingredient (AI) MF1 MF2 MF3 MF4 MF5 MF6 MF7 Main therapeutic indication / claim Usual posology in major pathology FurosemideI 20 25 18 18 30 Diuretic 20–80/120 mg/day ChlordiazepoxideII 8 8 8 8 10 Anxiolytic 30 mg (3 times/day) BupropionIII 120 100 140 150 130 Antidepressant 150 mg (2 times/day) MetformineIV 280 250 300 300 260 Antidiabetic 500 mg (2/3 times/day) ArtichokeV 110 400 Laxative 500 mg/day* Bitter orange (Citrus aurantium) VI 150 200 200 200 200 Appetite reducer 50–100 mg/day* Centella asiatica L.VII 400 400 750 Anti-cellulite, venotonic 60–120 mg/day* Cascara Sagrada (R. purshiana)VIII 100 130 120 Laxative 150–325 mg/day* PhenolphthaleinIX 65 100 90 85 Laxative 30–200 mg/day Glucomannan (A. konjac)X 500 Appetite reducer 1000–13,000 mg/day* Slimalluma (Caralluma fimbriata) XI 300 250 Appetite reducer 500 mg (2 times/day)* Roman superscripts identify the substance in the text. *RDD not well established. Discussion and conclusions Off-label uses of drugs and efficacy of sub therapeutic doses are questionable. D-II,III present risk of abuse and dependence. Combination of laxatives (MF 1, 2 and 6) is not recommended, increasing the chances of electrolyte imbalance and dehydration, and reducing absorption of ansa diuretics. Clinical data to support the claims and posology of botanicals is scarce and contradictory; moreover, potential side effects/interactions are at times unknown and adulteration/contamination is a risk. Of note is the potential for interaction of P-V (inhibiting several isoenzymes of CYP450) and the association of D-I/P-V may cause hypovolemia and hypocaliemia. Even if no additional interactions were found between molecules, combinations may increase the risk of adverse events. Severe/fatal interactions may occur with other drugs (e.g. D-II + opioids; D-III + MAO inhibitors), so knowledge of patient's clinical history and related medication is of the utmost importance, when prescribing and counselling. Indeed, evaluation of safety and efficacy of MF is a shared responsibility of doctor and pharmacist and requires robust scientific data, especially regarding botanicals. Slimming medication alone, without lifestyle changes, is not effective in the long term and may pose a health risk, as pointed out in this study.