Phentermine is a prescription medication classified as an anorexiant and used for weight loss in obese patients. Patients must be on a low-calorie diet and an exercise program. The medication is used in patients who have other risk factors, including diabetes and high blood pressure. Phentermine works by stimulating the hypothalamus, which is a gland found in the brain. This results in a decrease in appetite. The drug may produce many side effects; the patient should consult with a physician before starting therapy.
Use
Phentermine is intended to be used in the absence of other medications and for a short period of time. Patients should take the medication exactly as directly by a physician. Long-term therapy with phentermine may be used only when a physician deems it appropriate.
Dosage
The usual dose of phentermine is 8 mg administered three times a day. The medication should be given 30 minutes before meals or food. According to "Pharmacotherapy: A Pathophysiologic Approach," a patient may also take 30 mg once daily in the morning for effective appetite suppression.
Side Effects
Phentermine may raise the blood pressure and cause heart palpitations. The side effects on the brain are tremor or shaking, headache, dizziness and insomnia. The medication should not be taken close to bedtime, to avoid insomnia. Drugs.com reports that changes in behavior and mood include an enhanced sense of well-being, nervousness, hyperactivity and restlessness. Unpleasant taste, dry mouth and diarrhea are the gastrointestinal side effects seen with phentermine. Changes in sex drive and impotence, or inability to achieve an erection, may also occur.
Warnings
Phentermine should be used with caution in patients with mild to moderate high blood pressure, due to the increase in blood pressure and heart rate. Blood pressure may increase to a dangerous level if phentermine is administered with a monoamine oxidase inhibitor, such as isocarboxazid, selegiline or rasagiline. Patients on a monoamine oxidase inhibitor should wait 14 days after stopping the drug before starting therapy with phentermine. Patients with psychotic disorders, such as schizophrenia and bipolar disorder, should use the drug with caution because it may worsen the symptoms.
Contraindications
"Pharmacotherapy" explains that patients with glaucoma should avoid the use of phentermine because it dilates the pupils. Because phentermine has the potential for dependence, patients with a history of drug abuse should not be given the drug. According to the "Drug Information Handbook," patients with advanced hardening of the arteries, heart disease and severe hypertension cannot use phentermine. The medication is also contraindicated in patients less than 16 years of age.
References
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph T. Dipiro, Robert L. Talbert, et al.; 2008
- Drugs.com: Phentermine Side Effects
- "Drug Information Handbook"; Charles F. Lacy, Lora L. Armstrong, et al.; 2009
Member Comments