Limitations of Current Knowledge
| This section does not cite any references or sources. |
The limitation of drugs for obesity is that we do not fully understand the neural basis of appetite and how to modulate it. Appetite is clearly a very important instinct to promote survival. Arguably any drug that would abolish appetite may carry a high mortality risk and may be unsuitable for clinical use.
Because the human body uses various chemicals and hormones to protect its stores of fat (a reaction probably useful to our ancestors when food was scarce in the past,) there has not yet been found a 'silver bullet', or a way to completely circumvent this natural habit of protecting excess food stores. Because of this, anti-obesity drugs are not a practical long-term solution for people who are overweight.
In order to circumvent the number of feedback mechanisms that prevent most monotherapies from producing sustained large amounts of weight loss, it has been hypothesized that combinations of drugs may be more effective by targeting multiple pathways and possibly inhibiting feedback pathways that work to cause a plateau in weight loss. This was evidenced by the success of the combination of phentermine and fenfluramine or dexfenfluramine, popularly referred to phen-fen, in producing significant weight loss but fenfluramine and dexfenfluramine were pulled from the market due to safety fears regarding a potential link to heart valve damage. The damage was found to be a result of activity of fenfluramine and dexfenfluramine at the 5-HT2B serotonin receptor in heart valves. Newer combinations of SSRIs and phentermine, known as phenpro, have been used with equal efficiency as fenphen with no known heart valve damage due to lack of activity at this particular serotonin receptor due to SSRIs. There has been a recent resurgence in combination therapy clinical development with the development of 3 combinations: Qnexa (topiramate + phentermine), Empatic (bupropion + zonisamide) and Contrave (bupropion + naltrexone).
Read more about this topic: Anti-obesity Medication
Famous quotes containing the words limitations of, limitations, current and/or knowledge:
“The limitations of pleasure cannot be overcome by more pleasure.”
—Mason Cooley (b. 1927)
“No man could bring himself to reveal his true character, and, above all, his true limitations as a citizen and a Christian, his true meannesses, his true imbecilities, to his friends, or even to his wife. Honest autobiography is therefore a contradiction in terms: the moment a man considers himself, even in petto, he tries to gild and fresco himself.”
—H.L. (Henry Lewis)
“You are the current of the frozen stream,
Shadow invisible, ambushed and vigilant flame.”
—Allen Tate (1899–1979)
“I believe no satirist could breathe this air. If another Juvenal or Swift could rise up among us tomorrow, he would be hunted down. If you have any knowledge of our literature, and can give me the name of any man, American born and bred, who has anatomised our follies as a people, and not as this or that party; and who has escaped the foulest and most brutal slander, the most inveterate hatred and intolerant pursuit; it will be a strange name in my ears, believe me.”
—Charles Dickens (1812–1870)