Phentermine Hydrochloride

Phentermine hydrochloride capsules 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 ≥ 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 x 0.0254 = meters.

The limited usefulness of agents of this class, including phentermine, [se

Capsules containing 15 mg or 30 mg phentermine hydrochloride (equivalent to 12 mg or 24 mg phentermine base, respectively).

15 mg capsules: gray opaque cap, yellow opaque body with black imprint “N1” on both the cap and body, filled with powder.

30 mg capsules: blue cap, natural body with black imprint “N16” on both the cap and body, filled with powder.

• Nursing mothers: Discontinue drug or nursing taking into consideration importance of drug to mother. (
  4  CONTRAINDICATIONS

  • 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 [see

  USE IN SPECIFIC POPULATIONS

  ]
  
  • Nursing [see

  USE IN SPECIFIC POPULATIONS

  ]
  
  • 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
  • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines
  , 
  8.3  Nursing Mothers

  It is not known if phentermine is excreted in human milk; however, other amphetamines are present in human milk. Because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
  )
• Pediatric use: Safety and effectiveness not established. (
  8.4 Pediatric Use

  Safety and effectiveness in pediatric patients have not been established. Because pediatric obesity is a chronic condition requiring long-term treatment, the use of this product, approved for short-term therapy, is not recommended.
  )
• Geriatric use: Due to substantial renal excretion, use with caution. (
  8.5 Geriatric  Use

  In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

  This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.
  )
• Renal Impairment: Avoid use in patients with eGFR less than 15 mL/min/m² or end-stage renal disease requiring dialysis.

• Co-administration with other drugs for weight loss is not recommended (safety and efficacy of combination not established). (
  5.1 Co-administration with Other Drug Products for Weight Loss

  Phentermine hydrochloride capsules 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, co-administration of phentermine and these drug products is not recommended.
  )
• 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. (
  5.2 Primary Pulmonary Hypertension

  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 may 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.
  )
• Rare cases of serious regurgitant cardiac valvular disease have been reported. (
  5.3 Valvular Heart Disease

  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.
  )
• 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. (
  5.4 Development of Tolerance, Discontinuation in Case of Tolerance

  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. (
  5.5 Effect on the Ability to Engage in Potentially Hazardous Tasks

  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.
  )
• 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. (
  5.6 Risk of Abuse and Dependence

  Phentermine is related chemically and pharmacologically to amphetamine (d- and d

  l

  lamphetamine) 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

  and

  OVERDOSAGE

  .

  The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.
  )
• Concomitant alcohol use may result in an adverse drug reaction. (
  5.7 Usage with Alcohol

  Concomitant use of alcohol with phentermine may result in an adverse drug reaction.
  )
• Use caution in patients with even mild hypertension (risk of increase in blood pressure). (
  5.8 Use in Patients with Hypertension

  Use caution in prescribing phentermine for patients with even mild hypertension (risk of increase in blood pressure).
  )
• A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients. (
  5.9 Use in Patients on Insulin or Oral Hypoglycemic Medications for Diabetes Mellitus

  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

• Valvular heart disease [see

• Effect on the ability to engage in potentially hazardous tasks [see

• Withdrawal effects following prolonged high dosage administration [see