phentermine

REMS

Short-term treatment of obesity in conjunction with other interventions (dietary restriction, exercise); used to produce and maintain weight loss in patients with a BMI ≥30 kg/m² or ≥27 kg/m² in the presence of other risk factors (diabetes, hypertension, hyperlipidemia).

Action ⬆ ⬇

Decreases hunger by altering the chemical control of nerve impulse transmission in the appetite control center of the hypothalamus.

Therapeutic effects:

Appetite suppression with resultant weight loss.

Pharmacokinetics ⬆ ⬇

Absorption: Unknown.

Distribution: Unknown.

Metabolism/Excretion: Metabolized by the liver.

Half-Life: 19–24 hr.

Time/Action Profile ⬆ ⬇

( appetite suppression)

ROUTE		ONSET		PEAK		DURATION
PO		unknown		unknown		4 hr‡

‡For 8-mg tablets; ↑ to 12–14 hr for 30-mg capsules.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity or known intolerance to sympathomimetic amines or tartrazine;
Cardiovascular disease;
Hyperthyroidism;
Uncontrolled hypertension;
History of drug abuse;
Agitation;
Glaucoma;
Concurrent or recent (within 14 days) MAO inhibitor therapy;
Concurrent use of SSRI antidepressants;
OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

Diabetes mellitus;
Pedi: Children ≤16 yr (safety and effectiveness not established).

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypertension, palpitations, tachycardia, VALVULAR ABNORMALITIES

EENT: blurred vision

GI: constipation, diarrhea, dry mouth, nausea, unpleasant taste, vomiting

GU: changes in libido, erectile dysfunction

Neuro: CNS stimulation, confusion, dizziness, dysphoria, euphoria, headache, insomnia, mental depression, restlessness

Resp: PULMONARY HYPERTENSION

Interactions ⬆ ⬇

Drug-drug:

MAO inhibitors may result in hypertensive crisis; concurrent use contraindicated; do not use within 14 days of MAO inhibitors.
↑risk of adverse CNS events with alcohol.
Concurrent use with SSRI antidepressants is not recommended.
May ↓ insulin or oral hypoglycemic requirements in patients with diabetes.
Topiramate may ↑ levels and risk of toxicity.

Route/Dosage ⬆ ⬇

PO (Adults and Children >16 yr): Capsules or orally disintegrating tablets: 15–37.5 mg once daily; Lomaira: 8 mg 3 times daily.

Availability ⬆ ⬇

(Generic available)

Tablets (Lomaira): 8 mg
Orally disintegrating tablets: 15 mg; 30 mg; 37.5 mg
Capsules: 15 mg; 30 mg; 37.5 mg
In combination with:
topiramate (Qsymia). See Combination Drugs

Assessment ⬆ ⬇

Monitor weight and waist circumference every month for 1st 3 mo and then every 3 mo. Adjust concurrent medications (antihypertensives, antidiabetics, lipid-lowering agents) as needed.
Monitor for CNS effects (delirium, mania, psychosis).
Monitor BP and for pulmonary hypertension and valvular abnormalities (new-onset dyspnea, chest pain, syncope, lower extremity edema).
Monitor for development of tolerance (no longer effective in suppressing appetite).

Implementation ⬆ ⬇

PO: Avoid administering at nighttime. Cut scored tablets for half dose if needed. Administer before or 1–2 hr after breakfast. Administer Lomaira 30 min before meals.
Orally disintegrating tablets: Administer in morning with or without food. Gently remove tablet with dry hands from bottle and immediately place on top of tongue; then swallow with or without water.

Patient/Family Teaching ⬆ ⬇

Explain purpose and side effects of medication to patient. Advise patient to read Patient Information before starting therapy. Instruct patient to take medication as directed. Take missed dose as soon as remembered. Do not take two doses at the same time. Tolerance to anorectic effect usually develops within a few weeks. If this occurs, discontinue therapy. The recommended dose should not be exceeded. Medication may need to be discontinued gradually.
Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care provider before taking other medications.
Advise patient to adhere to a low-calorie diet and behavior modification counseling.
May cause drowsiness. Advise patient to avoid driving or other activities requiring alertness until response to medication is known.
Caution patient to avoid using alcohol or other CNS depressants with this medication.
Advise patient to notify health care provider immediately if chest pain, ↓ exercise tolerance, fainting, or swelling of the feet or lower legs occurs.
Caution patient not to use other weight loss products while taking phentermine.
Rep: May cause fetal harm. Advise women of reproductive potential to use effective contraception and avoid breastfeeding during therapy. Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇