Introduction
The food eaten by us every day contributes to the well-being of our bodies, as it is the basic source of nutrients for us. When we take in more calories than we spend, it leads to storage of fat in our body. If over-eating becomes a regular affair, it leads to an increase in weight and ultimately makes us obese. Obesity and overweight are defined as an excessive and abnormal accumulation of fat in the body which impairs the health of a person. Body mass index (BMI) is the most commonly used criteria for defining the health of a person according to his weight. Body mass index is defined as the ratio of a person’s weight in kilogram to the square of his height in meter (kg/m2). A person is said to be obese if his BMI is equal to or greater than 30. BMI between 25 and 29.9 is considered overweight. Overweight people are at higher risk of turning obese. Obesity is dangerous as it can lead to various ailments like cardiovascular diseases, diabetes, sleep apnea, osteoarthritis and cancer.
According to WHO, more than 1.9 billion adults across the globe were found to be obese in 2016. obesity and overweight have claimed more lives globally than underweight.[1]
Symptoms of Obesity
When the body mass index (BMI) is 30 or above, the person is diagnosed as obese. BMI can be calculated by diving the weight of a person in kilogram by the square of height in meter.
| BMI | Weight Status |
| Below 18.5 | Underweight |
| 18.5-24.9 | Normal |
| 25.0-29.9 | Overweight |
| 30-34.9 | Obese (Class I) |
| 35.0-39.9 | Obese (Class II) |
| 40.0 and higher | Extreme Obesity (Class III) |
BMI provides a reasonable estimate of fat in our body but it is not the direct measure of fat in a person’s body.
Following health problems can be observed by obese people in their everyday life:
1. Fatigue
2. Breathlessness
3. Joints and back pain
4. Difficulty in performing physical activities
5. Increased sweating
Treatment of Obesity
Obesity can be controlled by bringing in some lifestyle changes. Avoiding food items that promote fat accumulation and regular exercise help us in shedding excess weight. If you are still unable to shed those extra kilos, following medicines can be prescribed by your doctor:
1. Anorexiants
These are drugs that decrease appetite, leading to lower consumption of food and hence loss of weight. They stimulate the hypothalamus, which is a part of the limbic system of the brain responsible for controlling hunger and thirst. There are a number of pathways active in the hypothalamus through which hunger is controlled. Many drugs are available in market which work by interfering in these pathways thereby suppressing hunger. Some of the anorexiant medicines available in the market are:
a. Lorcaserin
Lorcaserin acts on the 5-HT receptors found in the hypothalamus and helps in controlling hunger.
Drug: lorcaserin hydrochloride
Brand name: Belviq
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Headache, decreased hemoglobin, hypoglycemia, constipation, dizziness, fatigue and xerostomia
b. Phentermine:
This drug helps in reducing hunger perception by acting on the hunger center of the brain. Outside the brain, phentermine stimulates the release of hormones epinephrine and norepinephrine which breaks down fat cells.
Drug: phentermine
Brand name: Adipex-P
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Dizziness, fainting, headache, numbness and swelling of feet
c. Sibutramine:
It is a drug which decreases the reuptake of serotonin, dopamine, and norepinephrine in the brain, thereby enhancing the feeling of satiety.
Drug: sibutramine hydrochloride
Brand name: Meridia
The U.S. FDA Status: Approved
Availability: Prescription
Dosage Form: Capsule
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Headache, back pain, flu, abdominal pain, chest pain, neck pain and accidental injury
d. Rimonabant
It selectively blocks the cannabinoid receptor CB1, which belongs to the endogenous cannabinoid system found throughout the body involved in controlling different physiological processes, like appetite.
Drug: rimonabant
Brand name: Acomplia
The U.S. FDA Status: Disapproved
Availability: Not available in the U.S.A.
Dosage Form: Tablet
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Nausea, upper respiratory tract infection, anxiety, irritability and insomnia
e. Topiramate
Although an anticonvulsant, topiramate is also used for weight reduction. This drug changes the taste perception in people by decreasing the production of saliva and curbs the pleasure associated with food. It also reduces the production of cortisol, which is a stress hormone and is responsible for increasing the production of insulin and hence appetite and food craving. It is usually prescribed along with phentermine hydrochloride.
Drug: phentermine hydrochloride and topiramate
Brand name: Qsymia
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Capsule
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Constipation, mood swings, insomnia, xerostomia, anxiety, nausea and depression
f. Diethylpropion
It is a noradrenergic agent that works by inhibiting the action of norepinephrine and dopamine neurotransmitters in the brain. This helps in appetite suppression and consequent weight loss.
Drug: diethylpropion
Brand name: Tenuate
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Blurred vision, chills, depression, dizziness, fainting, frequent urination and nosebleed
g. Bupropion:
Although an antidepressant, bupropion is used for weight loss as well as for smoking cessation. Obesity and depression often go hand in hand and together, they might be even more dangerous for a person. Weight loss is just a side effect of the drug and is being evaluated for treating obesity. Its exact mechanism of action is not yet understood. It is postulated that it affects certain pathways in the hypothalamus by stimulating the pro-opiomelanocortin (POMC)-producing neurons that have an anorectic effect.[2]
Drug: buproprion hydrochloride and naltrexone hydrochloride
Brand name: Contrave
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Constipation, headache, nausea, dizziness, insomnia, diarrhea, xerostomia and anxiety
h. Naltrexone
Naltrexone amplifies the action shown by bupropion and together, they display a more enhanced anorectic effect. They reduce food intake, increase the expenditure of energy, ultimately causing weight loss.
Drug: naltrexone hydrochloride
Brand name: Naltrexone hydrochloride
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Dizziness, drowsiness, vomiting, twitching, depression, fatigue and headache
I. Phendimetrazine
It is a CNS stimulant with anorectic effect. It activates the adrenergic system in the body which suppresses appetite and increases metabolism, leading to weight loss.
Drug: phendimetrazine tartrate
Brand name: Bontril PDM
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Anxiety, chest pain, dizziness, fainting, headache, nausea and numbness
j. Benzphetamine
It binds to the centrally located adrenergic receptors and stimulate the release of the neurotransmitters dopamine and/or epinephrine from the hypothalamus and bring about a decrease in appetite.
Drug: benzphetamine hydrochloride
Brand name: Benzphetamine hydrochloride
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Agitation, anxiety, confusion, irregular heartbeat, hallucinations and nightmares
k. Methamphetamine
It is a CNS stimulant that suppresses appetite. It can be used for short periods of time for reducing weight when all other therapies have failed. It causes rapid weight loss and carries a high risk of abuse. It is not clear whether the anorectic action shown by methamphetamine is due to appetite suppression or any other effect shown by it on CNS or metabolism.
Drug: methamphetamine
Brand name: Desoxyn
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Agitation, delusion, hallucination, blurred vision, dizziness, faintness, difficulty breathing and headache
l. Amphetamine
Although a CNS stimulant, amphetamine is also responsible for weight loss by suppressing appetite in the individuals. It increases energy expenditure by increasing the basal metabolism and muscular activity, decreasing water balance by increasing urine output or reducing water intake, by reducing food intake by decreasing motility of empty stomach, and decreasing food ingestion by reducing appetite.
Drug: amphetamine sulfate
Brand name: Evekeo
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Agitation, bladder pain, delusion, cloudy urine,feeling of unreality, difficulty breathing and headache
2. H2-Antagonists
H2 receptors are histamine receptors which are acted upon by histamine which is a neurotransmitter. It plays a role in energy regulation and feeding behavior, by acting on a hormone Leptin which acts on the hypothalamus to inhibit appetite.
Available as: Oral preparation
Drug: cimetidine
Brand name: Tagamet HB
The U.S. FDA Status: Approved
Availability: OTC
Dosage Form: Tablet
Indicated in Pregnancy: No, unless benefits outweigh risks
Alcohol Content: No
Side Effects: Diarrhea, dizziness, headache and somnolence
3. Incretin Mimetics
These drugs work by stimulating insulin secretions, which is a hormone secreted by the pancreas. Insulin decrease elevated blood glucose concentrations. This drug also slows the rate at which our stomach empties after eating which in turn makes us feel less hungry and prevents overeating.
Available as: Subcutaneous solution
Drug: liraglutide
Brand name: Saxenda
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Subcutaneous solution
Indicated in Pregnancy: Not recommended
Alcohol Content: No
Side Effects: Bladder pain, chills, cough, fever, diarrhea, joint pain and headache
4. Carbonic Anhydrase Inhibitor
These drugs promote persistent weight loss by preventing synthesis of new fat molecules i.e. lipogenesis, in mitochondria and cytosol.
Available as: Oral preparation
Drug: topiramate
Brand name: Topamax
The U.S. FDA Status: Approved
Availability: Prescription only
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Anxiety, confusion, diarrhea, dizziness, fatigue, nausea and depression
5. Peripherally Acting Anti-Obesity Agents
These drugs help in weight loss without affecting the brain or appetite. These work by inhibiting the breakdown of fats in intestines and thereby preventing the absorption of fats by intestinal lining.
Available as: Oral administration.
Drug: orlistat
Brand name: Xenical, Alli
The U.S. FDA Status: Approved
Availability: Prescription and OTC
Dosage Form: Tablet
Indicated in Pregnancy: No
Alcohol Content: No
Side Effects: Bowel urgency, oily evacuation, oily rectal leakage, frequent bowel movement, fecal incontinence, steatorrhea and flatulence
6. Laxatives and Diuretics
Medicines that help in stimulating bowel movement or soften the stool for easy passage are called laxatives. They are often used for treating constipation.
They are gaining popularity as weight loss aid as people believe that laxatives can help them in easy, quick and effortless weight loss by increasing the frequency of their bowel movement. A few studies indicate that nearly 4% of the general population is involved in laxative abuse for reducing weight.
It is true that laxatives might help in accelerating weight loss process, but the results are only temporary. Electrolyte imbalance, dehydration and dependence are some of the dangerous side effects associated with abuse of laxatives.
Diuretics, also called water pills, help in getting rid of the excess water from the body which can cause bloating and swelling. Devastating and irreversible side effects can occur in people indulging in long term use of diuretics.
Using diuretic and laxatives for weight loss only helps in getting rid of water weight and has no effect on the fat weight and hence the weight loss is only temporary.
Available as: Oral preparation
a. Laxatives
Drug: polyethylene glycol 3350
Brand name: Miralax
The U.S. FDA Status: Approved
Availability: OTC
Dosage Form: Oral solution
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: No
Side Effects: Severe or bloody diarrhea, rectal bleeding, bloating, upset stomach, dizziness and stomach pain
Drug: Psyllium husk
Brand name: Metamucil
The U.S. FDA Status: Not reviewed by the U.S. FDA
Availability: OTC
Dosage Form: Capsule
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: No
Side Effects: Rash, hives, wheezing, tightness in chest or throat, swelling in mouth and trouble swallowing
Drug: docuaste sodium
Brand name: Colace
The U.S. FDA Status: Not reviewed by the U.S. FDA
Availability: OTC
Dosage Form: Capsule
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: No
Side Effects: Rash, hives, wheezing, tightness in chest or throat, swelling in mouth and trouble swallowing
Drug: bisacodyl
Brand name: Dulcolax
The U.S. FDA Status: Not reviewed by the U.S. FDA
Availability: OTC
Dosage Form: Capsule
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: No
Side Effects: Abdominal discomfort, cramps, nausea, diarrhea, and fluid and electrolyte depletion
Drug: magnesium hydroxide
Brand name: Pedia-Lax
The U.S. FDA Status: Not reviewed by the U.S. FDA
Availability: OTC
Dosage Form: Chewable tablet
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: No
Side Effects: Rash, hives, wheezing, tightness in chest or throat, swelling in mouth and trouble swallowing
Drug: Sennosides
Brand name: Senokot
The U.S. FDA Status: Not reviewed by the U.S. FDA
Availability: OTC
Dosage Form: Tablet
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: Yes
Side Effects: Rash, hives, wheezing, tightness in chest or throat, swelling in mouth and trouble swallowing
b. Diuretics
Drug: magnesium salicylate
Brand name: Diurex
The U.S. FDA Status: Not reviewed by the U.S. FDA
Availability: OTC
Dosage Form: Capsule
Indicated in Pregnancy: Not recommended unless clearly required
Alcohol Content: No
Side Effects: Irritability, restlessness, abdominal distress, nausea, vomiting and anxiety
OTC Drugs
Differing criteria are used by drug regulatory bodies of different countries for deciding the over-the-counter availability of drugs. The various OTC drugs used in the treatment of obesity in different countries have been summarized in the table below.
| Name of the Country | OTC Drug(s) Available |
| Argentina | Cimetidine Bisacodyl |
| Australia | Cimetidine Orlistat Bisacodyl |
| Austria | Cimetidine Orlistat Bisacodyl |
| China | Cimetidine Orlistat Bisacodyl |
| Croatia | Orlistat Bisacodyl |
| Czech Republic | Orlistat Bisacodyl |
| Denmark | Cimetidine Orlistat Bisacodyl |
| France | Cimetidine Orlistat Bisacodyl |
| Germany | Orlistat Bisacodyl |
| Greece | Orlistat Bisacodyl |
| Hungary | Orlistat Bisacodyl |
| Ireland | Orlistat Bisacodyl |
| Italy | Cimetidine Orlistat Bisacodyl |
| Mexico | Cimetidine Orlistat Bisacodyl |
| Philippines | Orlistat Bisacodyl |
| Singapore | Cimetidine Orlistat Bisacodyl |
| South Korea | Cimetidine Bisacodyl |
| Spain | Cimetidine Orlistat Bisacodyl |
| Switzerland | Orlistat Bisacodyl |
| The Netherlands | Cimetidine Orlistat Bisacodyl |
| UK | Cimetidine Orlistat Bisacodyl |
| The U.S.A. | Cimetidine Orlistat Bisacodyl |
