Today, I had this friendly comment/question from a patient. Doctor, are you going to take phentermine if you are obese?

Right! Diet pills carry the "bad" name. Especially Phentermine, a stimulant like amphetamine, works in central nervous system to suppress your appetite and increase metabolism.

Does it help reduce the weight?

Yes, it does help with weight loss. But it tends to lose its effectiveness for weight loss if we use over longer period of time. As per my experience and in the literature, phentermine helps reduce weight maximally in first six months. After that the weight loss effect is less pronounced.

How much weight loss can phentermine achieve?

It actually varies. I do see larger reduction in the larger patients at the initial six months. With diet and exercise, it results even more weight loss.

For example, Mary tried an exercise program for a month and she lost a pound at the end of it. Then she tried the diet program for a month and lost about two pounds. In the third month she went to a doctor, got herself a prescription of phentermine, and lost one pound only. So she lost about 4 pounds overall.

But if she had been on diet, exercise and diet pill at the same time,  she would have lost way more than the four pounds (sometimes even upto 20-40 pounds) at the end of the first month. Diet, excercise and diet pills altogether work in synergy.

Does phentermine cause tolerance, dependence, addiction?

Be warned, phentermine is a scheduled substance and can cause all the above. It's efficacy can go down as it is used for longer time (tolerance). As it does cause euphoria and people sometimes can get hooked on to higher energy level feeling, it can lead to addiction. But I have not seen patients getting addicted on these medications unlike benzodiazepine (xanax, ativan etc.). Part of reason may be that I always stop using it when efficacy for weight loss drops, after several months of use.

What other side effects are related to phentermine?

Constipation, feeling jittery, insomnia are common. 

In the literature, it can raise the blood pressure, valvular disease, pulmonary hypertension, death if they are used together with dexfenfluramine (as phen-fen) which has been withdrawn from the market. 

In a study, two female patients were reported to have heart attacks (acute myocardial infarction) possibly caused by phentermine in Malaysia. A study reports that there is a heart valve damage ( aortic valve tear) possibly related with phentermine use in a man in US. At the same time, there is a study in Korea which patients who used phentermine were followed closely with echocardiogram or ultrasound of the heart. It did not show any heart valve or cardiovascular related abnormality .

But, there is a warning regarding the cardiovascular (heart related) side effects by using phentermine.

How do I know if I am damaging my heart (cardiovascular system) while I am on phentermine?

These are symptoms which may indicate to ask your doctor if you are damaging your heart or not. Difficulty breathing, chest pain, abnormal heart sound, blood pressure,easily tired, palpitation. If you develop any unusual symptoms while being on phemtermine, inform your doctor.  

Can the damage be reversible?

There were extensive research done on the Phentermine and fenfluramine (phen-fen) after effects. The studies report that when you stop taking the fenfluramine (which is no longer in US market), the valvular abnormalities (regurgitation) return to near normal for the tricuspid and mitral valve. But it does not apply the same for the aortic and pulmonary valve.

So what is the verdict?

I will not be afraid to take this medication for weight loss, if followings are met.

BMI >30                                                           

Waist line of >35 for ladies and >40 for men

Short term use

No underlying heart disease

Monitored by a physician closely

Together with diet and exercise

Awareness of warning symptoms that I should report to my physician

 By practicing medicine as a doctor, we do help in making difficult decisions for all of our patients. The basic principles on making decision is the same, either for obesity and weightloss or treatment of other medical diseases. Obesity is a disease like hypertension or diabetes or anything else.

I believe obesity is not a cosmetic issue, nor a personality issue. It is simply a medical disease. And  like other  medical diseases, it needs to be treated - with weight loss.

I teach my patients everyday
     

1. Not taking an appropriate medication despite needing it is wrong. Because you are walking on thin ice by not     taking the medication, it could crack anytime and drown you in ice cold water. 
2. Understanding the side effects, makes you prepared to take an early and watchful action if needed. Just like walking on the wet surface with caution when you see the sign of "slippery when wet".  
3. Natural, herbal substances are not necessarily safe compared to the prescription drugs. We just do not know what can they do to you. It has not been analysed / studied systematically like the prescription drugs.