Part 22: Introduction to Hormonal Weight Loss Drugs and the Latest Research Drugs

(III) Hormones

1. Thyroid hormones

Thyroid hormone medications such as thyroxine (T₄), triiodothyronine (T₃), and thyroxine tablets are traditional treatments for obesity. Thyroid hormones can increase metabolic rate and lead to weight loss. However, clinically, except for hypothyroid obesity, the effects are not significant at normal doses. This is because normal physiological doses, such as 10–60 mg of desiccated thyroxine tablets, taken orally once daily in the morning, or 50 mg of T₄ and 30 mg of T₃ daily, generally do not cause weight loss in obese patients with normal basal metabolism. This may be related to the suppression of endogenous thyroxine secretion after medication. Furthermore, transient hypothyroidism may occur after discontinuation of the medication.

Thyroid hormones can increase metabolic rate and reduce weight.

usage:

(1) Thyroxine tablets, taken orally, starting with 10 mg once a day in the morning. If there is no adverse reaction, increase by 10 mg every 7 days, generally up to 60 mg per day. After significant weight loss, the dose must be reduced to a maintenance dose of 30 mg/day. The reduction should be slow and maintained for several days to six months.

(2) T₄, orally, start with 10 micrograms once a day in the morning, then increase by 10 micrograms each week, and maintain the dose at 50 micrograms per day.

(3) T₃, orally, start with 5 micrograms once a day in the morning, then increase by 5 micrograms each week until it reaches 30 micrograms or until the therapeutic effect or palpitations and excessive sweating are observed.

Adverse reactions:

(1) When using this type of hormone, after weight loss or when palpitations, excessive sweating, or tension occur, the dosage should be gradually reduced and adjusted to a suitable maintenance dose.

(2) Increases heart rate and oxygen consumption. Use with caution in patients with coronary heart disease. Start with a small dose to avoid inducing angina. Generally, start with 10 mg/day for thyroid tablets, and increase by 10 mg every 7-10 days if there is no obvious discomfort. The usual dose is 30 mg per day. If this dose is ineffective after 3 months or if angina occurs, the medication should be discontinued.

(3) Liver function impairment. Elevated SGPT levels can return to normal after reducing or stopping the medication for 1-3 weeks. Liver function should be checked monthly while using this medication. If a mild elevation is observed, hepatoprotective drugs can be administered concurrently.

(4) Increased protein catabolism necessitates the addition of a high-protein and high-fiber diet.

2. Beta-adrenergic drugs

(1) BRL 26830A: This is a new adrenergic agonist that increases thermogenesis, raises the metabolic rate, and reduces body fat content. This drug is used on specific adipose tissue areas without affecting body density. It can reduce nitrogen loss and has no effect on heart rate or blood pressure. The usual dose is 200-400 mg/day, with a course of treatment of 6-8 weeks. It does not cause liver or kidney damage.

(2) LAY 104119 and LY79771: These drugs can competitively bind to ³H-diydro-dlprenolol receptors, increase the cAMP content in brown animal adipose tissue, stimulate lipid breakdown, and increase the release of norepinephrine from sympathetic nerve fibers in adipose tissue innervated by nerves, thereby enhancing thermogenesis. This norepinephrine tension occurs only in adipose tissue and does not occur in organs such as the heart and liver. It is a weight loss drug with highly selective thermogenic and metabolic-promoting effects.

3. Growth hormone (GH)

Clinically, it is often found that obese individuals have reduced growth hormone secretion. In metabolism, growth hormone primarily increases the mobilization of free fatty acids from fat storage sites, accelerating the body's utilization of free fatty acids, thereby reducing fat storage and achieving weight loss. Growth hormone increases the metabolic rate and the activity of 5'-deiodinase, promoting the conversion of T₃ to T₄, restoring serum T₃ concentration to normal during calorie restriction, alleviating negative nitrogen balance during dieting, and reducing protein loss. Generally, 5 mg daily is used, and the basal metabolic rate can increase after 1-3 days of initial use. However, due to the difficulty in obtaining the drug and the tendency to produce antibodies leading to failure, its application is not yet widespread.

(iv) Lipolytics

It is a freeze-dried protein product extracted from the anterior pituitary gland. It can promote the consumption and burning of fat in fat stores, activate lipolytic enzymes in adipose tissue, promote fat decomposition, and thus reduce weight.

This product has side effects such as edema and allergic reactions.

Contraindications: This product is contraindicated in patients with cardiovascular disease, diabetes, liver or kidney dysfunction, or those allergic to it.

Usage: Intramuscular injection, 50 mg each time, twice a day, for 10-20 days as one course of treatment.

(v) Newly researched drugs

1. Sibutramine

Sibutramine (also known as Qumei, Aokeqing, Kexiu, Tingli, Nometrine, etc., among which Nometrine is a German product) was the first prescription weight-loss drug approved by the State Food and Drug Administration in 2000. The drug achieves weight loss by inhibiting the reuptake of norepinephrine and serotonin. However, the drug still has central effects and is dose-dependent.

2. Orlist

Orlistat (also known as orlistat, brand name Xenical) is a novel non-central nervous system weight loss drug that was launched in China in 2001. It selectively acts on gastrointestinal lipases, thereby deactivating them and preventing them from hydrolyzing dietary fats (mainly triglycerides) into absorbable free fatty acids and monoacylglycerols. Undigested triglycerides cannot be absorbed by the body, thus reducing calorie intake and controlling weight.

3. L-carnitine

L-carnitine (also known as Kangliting) is an amino acid that is widely present in the human body. It can transport long-chain fats into the mitochondria for oxidation and decomposition. If there is a lack of L-carnitine in the body, it can affect fat metabolism and lead to obesity. Therefore, by supplementing L-carnitine, fat can be utilized and converted into energy for consumption, thereby achieving the goal of weight loss.

4. Leptin

Leptin is a polypeptide hormone expressed by obesity genes. It inhibits appetite by acting on the appetite center and increases the body's energy metabolism rate to achieve weight loss. It is known as a miraculous weight loss substance and has become a hot topic in the field of obesity and diabetes research in recent years. It is currently under investigation.

In the future, drugs with anti-lipogenic and anti-adipocyte effects may be used to treat obesity. With the development of gene technology, artificially altering genes may also be an effective method for treating obesity.

Most weight-loss products on the Chinese market are health supplements with varying degrees of lipid-lowering effects, unlike weight-loss drugs. The World Health Organization has clear regulations for weight-loss products, stating that they should not cause anorexia, diarrhea, or fatigue after use. Commercially available and effective weight-loss products often contain various effective weight-loss ingredients that promote blood and lymphatic circulation, regulate endocrine function, and increase fat breakdown to achieve weight loss and lipid-lowering effects. Weight-loss products should not be used blindly. They should only be used under the guidance of medical professionals if a certain level of obesity has been achieved and there are no other medical conditions. If your weight is within the normal range or slightly above normal, it is best not to use weight-loss products. Instead, you can achieve weight loss through adjusting your diet and lifestyle, and engaging in appropriate exercise.