Home Drug Guide Phenmetrazine Hydrochloride

Drug Guide

Generic Name

Phenmetrazine Hydrochloride

Brand Names Preludin

Classification

Therapeutic: Appetite Suppressant / Stimulant

Pharmacological: Amphetamine-like Stimulant

FDA Approved Indications

Short-term treatment of obesity as an appetite suppressant

Mechanism of Action

Phenmetrazine is a central nervous system stimulant that releases catecholamines (dopamine and norepinephrine) and inhibits their reuptake, leading to increased sympathetic activity which suppresses appetite.

Dosage and Administration

Adult: Typically 25-50 mg orally two to three times daily before meals. Dose may be adjusted based on response and tolerability.

Pediatric: Not approved for pediatric use.

Geriatric: Use with caution, start at lower end of dosage range due to increased sensitivity and comorbidities.

Renal Impairment: Use cautiously; dose adjustment may be necessary.

Hepatic Impairment: Use cautiously; monitor closely. Specific dosage adjustments are not well established.

Pharmacokinetics

Absorption: Rapidly absorbed from gastrointestinal tract.

Distribution: Widely distributed, crosses the blood-brain barrier.

Metabolism: Metabolized minimally; primarily excreted unchanged in urine.

Excretion: Mostly via renal excretion, with a half-life of approximately 4-7 hours.

Half Life: Approximately 4-7 hours.

Contraindications

History of cardiovascular disease, hypertension, hyperthyroidism, glaucoma, drug abuse or dependence, MAOI use within 14 days.
Known hypersensitivity to phenmetrazine.

Precautions

Use cautiously in patients with psychiatric disorders, history of substance abuse, or underlying medical conditions affecting cardiovascular status. Risk of dependence and abuse is significant.

Adverse Reactions - Common

Insomnia (Frequent)
Dry mouth (Frequent)
Restlessness (Frequent)
Elevated blood pressure (Frequent)

Adverse Reactions - Serious

Hypertensive crisis (Rare)
Psychosis or hallucinations (Rare)
Dependence or addiction (Serious risk)

Drug-Drug Interactions

MAOIs: risk of hypertensive crisis
Other stimulants: additive effects
Antihypertensives: may diminish effect

Drug-Food Interactions

Avoid caffeine and other stimulants

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, heart rate, mental status, signs of abuse or dependence.

Diagnoses:

Risk for hypertension
Impaired sleep pattern
Risk for substance dependence

Implementation: Administer as prescribed, monitor vital signs and mental status regularly.

Evaluation: Assess effectiveness in appetite suppression, monitor for adverse reactions or signs of misuse.

Patient/Family Teaching

Take medication exactly as prescribed.
Avoid caffeine and other stimulants.
Report any chest pain, palpitations, or mental changes.
Do not abruptly discontinue medication to avoid withdrawal symptoms.

Special Considerations

Black Box Warnings:

Potential for abuse and dependence.
Risk of serious cardiovascular events, including sudden death, stroke, and heart attack, especially in patients with underlying cardiovascular disease.

Genetic Factors: None established.

Lab Test Interference: May affect measurements of certain laboratory tests related to catecholamine levels.

Overdose Management

Signs/Symptoms: Severe hypertension, hyperthermia, agitation, confusion, hallucinations, seizures, cardiac arrhythmias.

Treatment: Supportive care, control of blood pressure, cooling measures for hyperthermia, benzodiazepines for agitation or seizures, activated charcoal if ingestion is recent.

Storage and Handling

Storage: Store at room temperature away from light and moisture.

Stability: Stable when stored properly, expiry date should be checked.