New Obesity Drug, Maunjaro's Mechanism and Side EffectsDirector of the Department of Family Medicine at the Central Veterans Hospital

1. Maunjaro's Mechanism and Medicinal Effect, Injection Target

Maunjaro's basic mechanism is a decrease in appetite. Because it has an appetite-reducing effect, you'll eat less food, which will result in weight loss. When you think of drugs that have an "appetite-lowering effect", you probably think of psychotropic drugs a lot. Drugs in the same family as Maunjaro have a different appetite reduction mechanism than psychotropic drugs because they act on the sugar metabolism process and cause appetite-lowering effects.

For administration targets, it is basically based on people with severe obesity. In Korea, the body mass index (BMI) is set as a standard of 30 kg/m², so people with extreme obesity may be eligible, but I think that people who are slightly obese or who are not overweight but have severe abdominal obesity may also be eligible.

 

2. Side effects of Maunjaro

 

Studies have shown that digestive side effects such as nausea, vomiting, diarrhea and constipation are more common than mental side effects. So, in the case of nausea, it's a fairly common side effect, and it's estimated that at least one-third of people who take the maximum dose of Maunjaro of 15 mg will experience nausea. It is expected to improve little by little over time, but some people stop taking the drug because of this.

 

3. As long as the injections are good, do I not need to restrict my diet or exercise?

 

I am in the negative about this. This is true in the case of Maunjaro, as well as drugs such as Saxenda and Wegovy, which will be released in Korea in the future, and the weight loss effects are all the results of clinical trials.

However, clinical trials are a little different from actual data. In other words, it was done in a tightly controlled setting. The clinical trial consists of a drug group and a placebo group, and the group that received the dummy drug had a weight loss effect of about 3%. In other words, both of them had some dietary adjustments and exercise. Articles tout it as a pill that can help you lose 24 kilograms with just one injection, but it's not really that kind of medicine. Of course, it's a medicine that has to be given once a week, and if you eat the same meal while administering the medicine, it won't work.

 

So this could be a little bit of a different story. There are two mechanisms by which we eat. One is appetite and the other is gluttony. Appetite can be suppressed with medication, but food cravings cannot be suppressed with drugs. The desire to eat delicious food and the memories of having fun eating food are also factors that drive food cravings, and some people may have a stronger craving. For such people, these drugs are not very effective.

 

Therefore, it is not just medication, but of course diet and exercise are necessary, and it is important to have counseling and things like that so that you can adjust your diet.

 

4. Is it a drug that works on appetite, not gluttony?

 

In fact, not much has been discovered yet, but in the case of Saxenda, which is a drug of a similar class to this drug, there are studies that show that it has the effect of reducing food cravings to a certain extent, but the effect is still a little unclear. So, even in the case of Maunjaro, it will take some experience to know, but I think appetite control will be the main mechanism.

 

5. Can Maunjaro, Saxenda, and Wegovy be seen as having a similar mechanism?

 

Basically, they all have similar mechanisms. However, in the case of Maunjaro, you can think of it as a synergistic effect by acting on one receptor more.

 

Side effects are similar across the board. However, there is a concern that compared to Saxenda, Wegovy and Maunjaro will have a slightly more nauseating side effect. I think we'll find out after it's released.

 

6. In the case of severe obesity, can drug treatment such as Maunjaro be sufficiently effective rather than bariatric metabolic surgery?

 

Bariatric surgery and drug therapy are two different things. Recent reports have shown that Maunjaro has a weight loss of more than 22%. Therefore, it is correct that it has a weight loss effect that is almost equivalent to bariatric surgery for one year. Does this make bariatric surgery meaningless? It's not. In the case of Maunjaro, as I said before, once you get a shot, you lose weight, and it's not a magic pill that lasts a lifetime. In order to maintain that weight, you have to take the drug continuously, and if you stop taking the drug after about a year, you will definitely get a yo-yo effect.

On the other hand, in the case of bariatric surgery, the procedure can be difficult, but it has a great advantage in that it can reduce weight continuously, so I don't think it will be a substitute for surgery even if drug treatment advances.

 

However, if the body mass index exceeds 30 kg/m² or if the abdominal obesity is so severe that it is difficult for the patient to carry out daily activities, I recommend surgery for obesity first. However, some patients find it difficult to accept such things, so in such cases, medication may be used. Also, I don't have long-term data on drugs like Maunjaro yet, so it's hard for me to say, but as dramatic as the weight loss effect is, there is a concern that the yo-yo effect when you stop taking it will be quite large.

 

7. If I am not very obese, can I still receive medication such as Maunjaro?

 

I think I should speak from a medical point of view. In fact, so far, Saxenda and Wegovy have been shown to reduce the risk of developing cardiovascular disease in mild obesity or overweight patients. That's why I'm in favor of giving such drugs to people with mild obesity or overweight to a certain degree.

And in the case of Maunjaro, there is not yet long-term data, so there is a lack of data on whether the drug reduces the risk of cardiovascular complications and death, as well as weight loss. So I can't tell you that, but if the data shows that this drug can also reduce the risk of cardiovascular complications and death, I would probably recommend it to people with mild obesity. However, for those who are looking to lose weight due to weddings or other events, the short-term use of these drugs is not recommended because it can cause a serious yo-yo effect.