Phentermine, technically known as ‘phenyl-teriary-butylamine’, is an appetite suppressor that is commonly used aid weight loss in obese patients along with exercise and diet. Unlike other more dangerous fat burning drugs it works simply by reducing cravings for food and as such is less dangerous. Still it should only be used in cases where exercise and diet modification alone proves unsuccessful and is only prescribed where obesity presents a serious health risk; and patients do report some negative side effects from phentermine.
The mechanism of the appetite-suppression works by affecting the hypothalamus which is responsible for releasing many of the brain’s hormones and chemicals. Here it triggers the release of norepinephrine which is an endorphin associated with the fight-or-flight response and that has the ability to suppress appetite. Obviously this has an evolutionary advantage
Some negative side effects from phentermine are obviously going to occur then that are similar to the fight or flight response that sees individuals experiencing increased heart rate (though this can sometimes be countered by compensatory action in the body) and which may also result in restlessness and insomnia. Norepinephrine can also increase blood pressure through its effect of increasing the vascular tone from a-adrenergic receptor activation. In high doses phentermine can also cause the hypothalamus to trigger other chemicals such as dopamine and serotonin, though clinical use does not involve such high doses. However it’s possible that this could create a problem if taken with other drugs.
In such cases the negative side effects from phentermine are exacerbated and there are many other conditions under which it should not be used. Including cases where the individual is allergic, are taking other drugs such as dexfenfluramine, furazolidone or monoamine oxidase inhibitors, is pregnant, have disorders of the brain or spinal chord, have hardening of the arteries, have diabetes or have already high blood pressure or cholesterol.
Even where it does not interact with other conditions or medications however, phenermine can still cause unpleasant side effects though these are fairly rare including. These include blurred vision, dry mouth, confusion, affected libido, diarrhoea, dizziness, headache, arrhythmia, heart burn, nausea and vomiting. In very rare cases patients have reported convulsions, hallucinations, hostility, mania and depression, panic, stomach cramps, tremors, seizures and fever.