DIETHYLPROPION Drug Interactions: What You Need to Know

Drug Interactions Because diethylpropion hydrochloride extended release tablets, 75 mg are monoamines, hypertension may result when either agent is used with monoamine oxidase (MAO) inhibitors (See CONTRAINDICATIONS ). Efficacy of diethylpropion with other anorectic agents has not been studied and the combined use may have the potential for serious cardiac problems; therefore, the concomitant use with other anorectic agents is contraindicated. Antidiabetic drug requirements (i.e., insulin) may be altered. Concurrent use with general anesthetics may result in arrhythmias. The pressor effects of diethylpropion and those of other drugs may be additive when the drugs are used concomitantly; conversely, diethylpropion may interfere with antihypertensive drugs (i.e., guanethidine, a-methyldopa). Concurrent use of phenothiazines may antagonize the anorectic effect of diethylpropion.

CONTRAINDICATIONS Pulmonary hypertension, advanced arteriosclerosis, hyperthyroidism, known hypersensitivity or idiosyncrasy to the sympathomimetic amines, glaucoma, severe hypertension. (See PRECAUTIONS .) Agitated states. Patients with a history of drug abuse. Use in combination with other anorectic agents is contraindicated. During or within 14 days following the administration of monoamine oxidase inhibitors, hypertensive crises may result.

WARNINGS Diethylpropion hydrochloride extended release tablets, 75 mg should not be used in combination with other anorectic agents, including prescribed drugs, over-the-counter preparations, and herbal products. In a case-control epidemiological study, the use of anorectic agents, including diethylpropion, was associated with an increased risk of developing pulmonary hypertension, a rare, but often fatal disorder. The use of anorectic agents for longer than 3 months was associated with a 23-fold increase in the risk of developing pulmonary hypertension. Increased risk of pulmonary hypertension with repeated courses of therapy cannot be excluded. The onset or aggravation of exertional dyspnea, or unexplained symptoms of angina pectoris, syncope, or lower extremity edema suggest the possibility of occurrence of pulmonary hypertension. Under these circumstances, diethylpropion hydrochloride extended release tablets, 75 mg should be immediately discontinued, and the patient should be evaluated for the possible presence of pulmonary hypertension. Valvular heart disease associated with the use of some anorectic agents such as fenfluramine and dexfenfluramine has been reported. Possible contributing factors include use for extended periods of time, higher than recommended dose, and/or use in combination with other anorectic drugs. Valvulopathy has been very rarely reported with diethylpropion hydrochloride extended release tablets, 75 mg monotherapy, but the causal relationship remains uncertain. The potential risk of possible serious adverse effects such as valvular heart disease and pulmonary hypertension should be assessed carefully against the potential benefit of weight loss. Baseline cardiac evaluation should be considered to detect preexisting valvular heart diseases or pulmonary hypertension prior to initiation of diethylpropion hydrochloride extended release tablets, 75 mg treatment. Diethylpropion hydrochloride extended release tablets, 75 mg are not recommended in patients with known heart murmur or valvular heart disease. Echocardiogram during and after treatment could be useful for detecting any valvular disorders which may occur. To limit unwarranted exposure and risks, treatment with diethylpropion hydrochloride extended release tablets, 75 mg should be continued only if the patient has satisfactory weight loss within the first 4 weeks of treatment (e.g., weight loss of at least 4 pounds, or as determined by the physician and patient). Diethylpropion hydrochloride extended release tablets, 75 mg are not recommended for patients who used any anorectic agents within the prior year. If tolerance develops, the recommended dose should not be exceeded in an attempt to increase the effect; rather, the drug should be discontinued. Diethylpropion hydrochloride extended release tablets, 75 mg 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. Prolonged use of diethylpropion hydrochloride may induce dependence with withdrawal syndrome on cessation of therapy. Hallucinations have occurred rarely following high doses of the drug. Several cases of toxic psychosis have been reported following the excessive use of the drug and some have been reported in which the recommended dose appears not to have been exceeded. Psychosis abated after the drug was discontinued. When central nervous system active agents are used, consideration must always be given to the possibility of adverse interactions with alcohol.