Phentermine

Phentermine hydrochloride tablets are indicated as a short-term (a few weeks) adjunct in a regimen of weight reduction based on exercise, behavioral modification and caloric restriction in the management of exogenous obesity for patients with an initial body mass index greater than or equal to 30 kg/m 2, or greater than or equal to 27 kg/m 2 in the presence of other risk factors (e.g., controlled hypertension, diabetes, hyperlipidemia). Below is a chart of body mass index (BMI) based on various heights and weights. BMI is calculated by taking the patient’s weight, in kilograms (kg), divided by the patient’s height, in meters (m), squared. Metric conversions are as follows: pounds ÷ 2.2 = kg, inches x 0.0254 = meters.

Phentermine is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, amphetamine (d- and d/l-amphetamine). Drugs of this class used in obesity are commonly known as “anorectics” or “anorexigenics.” It has not been established that the primary action of such drugs in treating obesity is one of appetite suppression since other central nervous system actions, or metabolic effects, may also be involved.

Dosage should be individualized to obtain an adequate response with the lowest effective dose. Late evening administration should be avoided (risk of insomnia). Phentermine hydrochloride tablets can be taken with or without food. Limit the dosage to 15 mg daily for patients with severe renal impairment (eGFR 15 to 29 mL/min/1.73 m 2 )

History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) During or within 14 days following the administration of monoamine oxidase inhibitors Hyperthyroidism Glaucoma Agitated states History of drug abuse Pregnancy Nursing Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension). During or within 14 days following the administration of monoamine oxidase inhibitors. Hyperthyroidism. Glaucoma. Agitated states. History of drug abuse. Pregnancy. Nursing.

Coadministration with other drugs for weight loss is not recommended (safety and efficacy of combination not established). Rare cases of primary pulmonary hypertension have been reported. Phentermine should be discontinued in case of new, unexplained symptoms of dyspnea, angina pectoris, syncope or lower extremity edema. Rare cases of serious regurgitant cardiac valvular disease have been reported. Tolerance to the anorectic effect usually develops within a few weeks. If this occurs, phentermine should be discontinued. The recommended dose should not be exceeded. Phentermine may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle. Risk of abuse and dependence. The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.

The following adverse reactions are described, or described in greater detail, in other sections: - Primary pulmonary hypertension - Valvular heart disease - Effect on the ability to engage in potentially hazardous tasks - Withdrawal effects following prolonged high dosage administration The following adverse reactions to phentermine have been identified: Cardiovascular Primary pulmonary hypertension and/or regurgitant cardiac valvular disease, palpitation, tachycardia, elevation of blood pressure, ischemic events. Central Nervous System Overstimulation, restlessness, dizziness, insomnia, euphoria, dysphoria, tremor, headache, psychosis. Gastrointestinal Dryness of the mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances. Allergic Urticaria. Endocrine Impotence, changes in libido.

Monoamine oxidase inhibitors: Risk of hypertensive crisis. Alcohol: Consider potential interaction. Insulin and oral hypoglycemics: Requirements may be altered. Adrenergic neuron blocking drugs: Hypotensive effect may be decreased by phentermine.

Store at 20 o to 25 o C (68 o to 77 o F).