PHENTERMINE HYDROCHLORIDE- phentermine hydrochloride tablet
Blenheim Pharmacal, Inc.
Phentermine hydrochloride is 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 ≥ 30 kg/m2 , or ≥ 27 kg/m2 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 × 0.0254 = meters.
|BODY MASS INDEX (BMI), kg/m2|
The limited usefulness of agents of this class, including phentermine hydrochloride tablets, [see Clinical Pharmacology (12.1, 12.2)] should be measured against possible risk factors inherent in their use such as those described below.
Dosage should be individualized to obtain an adequate response with the lowest effective dose.
The usual adult dose is one tablet (37.5 mg) daily, as prescribed by the physician, administered before breakfast or 1 to 2 hours after breakfast. The dosage may be adjusted to the patient’s need. For some patients, half tablet (18.75 mg) daily may be adequate, while in some cases it may be desirable to give half tablets (18.75 mg) two times a day.
Phentermine hydrochloride is not recommended for use in pediatric patients ≤ 16 years of age.
Late evening medication should be avoided because of the possibility of resulting insomnia.
Tablets containing 37.5 mg phentermine hydrochloride (equivalent to 30 mg phentermine base).
- 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
- Agitated states
- History of drug abuse
- Pregnancy [see Use in Specific Populations (8.1) ]
- Nursing [see Use in Specific Populations (8.3) ]
- Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines
Phentermine hydrochloride tablets are indicated only as short-term (a few weeks) monotherapy for the management of exogenous obesity. The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. Therefore, coadministration of phentermine and these drug products is not recommended.
Primary Pulmonary Hypertension (PPH) – a rare, frequently fatal disease of the lungs – has been reported to occur in patients receiving a combination of phentermine with fenfluramine or dexfenfluramine. The possibility of an association between PPH and the use of phentermine alone cannot be ruled out; there have been rare cases of PPH in patients who reportedly have taken phentermine alone. The initial symptom of PPH is usually dyspnea. Other initial symptoms include angina pectoris, syncope or lower extremity edema. Patients should be advised to report immediately any deterioration in exercise tolerance. Treatment should be discontinued in patients who develop new, unexplained symptoms of dyspnea, angina pectoris, syncope or lower extremity edema, and patients should be evaluated for the possible presence of pulmonary hypertension.
Serious regurgitant cardiac valvular disease, primarily affecting the mitral, aortic and/or tricuspid valves, has been reported in otherwise healthy persons who had taken a combination of phentermine with fenfluramine or dexfenfluramine for weight loss. The possible role of phentermine in the etiology of these valvulopathies has not been established and their course in individuals after the drugs are stopped is not known. The possibility of an association between valvular heart disease and the use of phentermine alone cannot be ruled out; there have been rare cases of valvular heart disease in patients who reportedly have taken phentermine alone.
When tolerance to the anorectant effect develops, the recommended dose should not be exceeded in an attempt to increase the effect; rather, the drug should be discontinued.
Phentermine may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; the patient should therefore be cautioned accordingly.
Phentermine is related chemically and pharmacologically to amphetamine (d- and d/l-amphetamine) and other related stimulant drugs have been extensively abused. The possibility of abuse of phentermine should be kept in mind when evaluating the desirability of including a drug as part of a weight reduction program. See Drug Abuse and Dependence (9) and Overdosage (10).
The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.
Concomitant use of alcohol with phentermine may result in an adverse drug reaction.
Use caution in prescribing phentermine for patients with even mild hypertension (risk of increase in blood pressure).
A reduction in insulin or oral hypoglycemic medications in patients with diabetes mellitus may be required.
The following adverse reactions are described, or described in greater detail, in other sections:
- Primary pulmonary hypertension [see Warnings and Precautions (5.2) ]
- Valvular heart disease [see Warnings and Precautions (5.3) ]
- Effect on the ability to engage in potentially hazardous tasks [see Warnings and Precautions (5.5) ]
- Withdrawal effects following prolonged high dosage administration [see Drug Abuse and Dependence (9.3) ]
The following adverse reactions to phentermine have been identified:
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.
Dryness of the mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances.
Impotence, changes in libido.
Use of phentermine is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hypertensive crisis.
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