Phentermine is a sympathomimetic amino, which means which is a stimulant very similar to amphetamine. This has a purpose: it is a short-term drug therapy (medication) for weight loss in obese patients. Although it is approved for only one indication, its effects are felt in multiple body systems. Phentermine should not be used with other medications because of possible dangerous interactions.
Phentermine causes vasoconstriction or hardening and thinning of blood vessels. This causes the elevation of blood pressure. The National Institutes of Health advises that this medication should be used with caution in patients with a history of hypertension, including mild hypertension. A patient who ingests phentermine should check his blood pressure daily to know of an elevation in it.
The effects of phentermine include cardiac stimulation. The heart muscle becomes increasingly excitable, which means that it is more easily stimulated to beat. Doctors Billie Ann Wilson, Margaret Shannon and Kelly Shields, authors of "Pearson Nurse's Drug Guide 2010," explain how this can lead to irregular heart rhythms or arrhythmias, for example, phentermine can cause a rapid heartbeat, called tachycardia. This is prolonged, can cause chest pain, shortness of breath and syncope or faintness Patients can also experience palpitations or strong heartbeats that can be felt in the chest or throat This drug also causes more serious arrhythmias such as contractions premature ventricular (extra ventricular beats) or ventricular tachycardia, where they only beat the ventricles (lower chambers of the heart) and beat very quickly Blood pressure can not keep up with this A patient who ingests phentermine must have a cardiac evaluation before ingest the medication, and should also be evaluated during therapy.
The effects of Phentermine stimulation also affect the central nervous system. Patients who ingest it may present extreme anxiety due to over stimulation. Nervousness, restlessness and insomnia are symptoms of anxiety that are often reported by patients who take phentermine.
The NIH reports that the effects of ferterine appetite suppression are greatest during the first two weeks of therapy. The reason, or even the way in which this happens, is not clear. The medication causes altered taste sensations, constipation and dry mouth. These symptoms, together with anxiety and a higher metabolic rate, can cause loss of appetite and weight loss.