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.
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
Phentermine is related chemically and pharmacologically to amphetamine (d- and dll-amphetamine) and other related stimulant drugs have been extensively abused. The possibility of abuse of phentermine should be kept in mind when eva luating the desirability of including a drug as part of a weight reduction program. See ADVERSE REACTIONS/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.
Usage with Alcohol
Concomitant use of alcohol with phentermine may result in an adverse drug reaction.
Use in Patients with Hypertension
Use caution in prescribing phentermine for patients with even mild hypertension (risk of increase in blood pressure).
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.
PRECAUTIONS
Information for Patients
Patients must be informed that phentermine hydrochloride is 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, and that coadministration of phentermine with other drugs for weight loss is not recommended (see INDICATIONS AND USAGE and WARNINGS).
Patients must be instructed on how much phentermine to take, and when and how to take it (see DOSAGE AND ADMINISTRATION).
Advise pregnant women and nursing mothers not to use phentermine (see PRECAUTIONS).
Patients must be informed about the risks of use of phentermine (including the risks discussed in WARNINGS and PRECAUTIONS), about the symptoms of potential adverse reactions and when to contact a physician and/or take other action. The risks include, but are not limited to:
• Development of primary pulmonary hypertension (see WARNINGS)
• Development of serious valvular heart disease (see WARNINGS)
• Effects on the ability to engage in potentially hazardous tasks (see WARNINGS)
• The risk of an increase in blood pressure (see WARNINGS and ADVERSE REACTIONS)
• The risk of interactions (see CONTRAINDICATIONS, WARNINGS, and PRECAUTIONS/DRUG INTERACTIONS)
The patients must also be informed about
• the potential for developing tolerance and actions if they suspect development of tolerance (see WARNINGS) and
• the risk of dependence and the potential consequences of abuse (see WARNINGS, DRUG ABUSE AND DEPENDENCE, and OVERDOSAGE).
Tell patients to keep phentermine in a safe place to prevent theft, accidental overdose, misuse or abuse. Selling or giving away phentermine may harm others and is against the law.
Drug Interactions
Monoamine Oxidase Inhibitors
Use of phentermine is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hyper |
