Obesity is a growing problem, particularly in the western world, with a large proportion of the total population expected to be overweight in the near future (Davies, 2023). Despite the effectiveness of behavioural and lifestyle changes, there is growing scope for pharmacological and even surgical interventions. The mainstay of pharmacological intervention in the UK is orlistat which is a drug that prevents fat absorption in the intestine and thus reduces the proportion of dietary calories absorbed. Although patients are able to buy 60 mg orlistat (GlaxoSmithKline Consumer Healthcare, 2017) over the counter from pharmacies, they may also be able to receive a higher strength preparation on prescription if they have a body mass index (BMI) ≥30 kg/m2 or ≥28 kg/m2 with associated risk factors (National Institute for Health and Care Excellence (NICE), 2014).
Case study
Consider a patient who has approached you for a prescription for orlistat who is keen to lose weight and has the following anthropometrics: male, 44 years old, 185 cm tall, 113 kg. He has no other medical conditions or medications.
QUESTION 1
Does this patient meet the NICE criteria for commencing orlistat (NICE, 2014)? Calculate his BMI using the formula:
- BMI (kg/m2)=weight (kg)/height (m)2 (Centers for Disease Control and Prevention, 2023).
QUESTION 2
How much weight would he need to lose in order to be in the bracket of ‘healthy weight’ with a BMI of 20–25 kg/m2?
Treatment with orlistat should be discontinued after 12 weeks if patients have been unable to lose at least 5 % of their initial body weight, as measured at the start of therapy (Neon Healthcare, 2008; NICE, 2014).
QUESTION 3
What weight will our patient need to reach after 12 weeks to enable him to continue being treated with orlistat?
Patients should be warned to limit fat per meal because the reduced ability to absorb fat means high intakes cannot be absorbed and will produce a laxative effect as there is a lot of fat being passed undigested. The product information suggests a maximum of 30% of total daily calories can be from fat and this should be split evenly among the three main meals (Neon Healthcare, 2008).
QUESTION 4
Assuming our patient has a planned daily calorie intake of 2000 kcal, how many grams of fat could a patient consume per meal without expecting adverse effects according to the product information? Each gram of fat provides 9 kcal (Donovan and Hignet, 2023).
QUESTION 5
At week 12 of treatment, if our patient reports his weight has dropped to 17st 7lb, has he met the criteria to continue treatment or has his loss been too small to justify continuation?