Phentermine HCl
A to Z Drug Facts
(FEN-ter-meen) |
Phentermine HCl |
Tablets: 8 mg (equiv. to 6.4 mg base), 30 mg (equiv. to 24 mg base), 37.5 mg (equiv. to 30 mg base) |
Capsules: 15 mg (equiv. to 12 mg base), 18.75 mg (equiv. to 15 mg base), 37.5 mg (equiv. to 30 mg base) |
Ionamin |
Capsules: 15 mg phentermine resin, 15 mg (as resin complex), 30 mg (as resin complex) |
Adipex-P |
Tablets: 37.5 mg (equiv. to 30 mg base) |
Capsules: 37.5 mg (equiv. to 30 mg base) |
Obe-Nix 30 |
Capsules: 37.5 mg (equiv. to 30 mg base) |
Phentermine Resin |
Capsules: 15 mg (as resin complex), 30 mg (as resin complex) |
Class: CNS stimulant/Anorexiant |
Actions May stimulate satiety center in brain, causing appetite suppression.
Indications Short-term (few weeks) adjunct to diet plan to reduce weight.
Contraindications Hypersensitivity to sympathomimetic amines; advanced arteriosclerosis; symptomatic cardiovascular disease; moderate to severe hypertension; hyperthyroidism; glaucoma; agitated states; history of drug abuse; during or within 14 days following the administration of an MAOI.
Route/Dosage
8 mg Dose
ADULTS and CHILDREN (³ 12 yr): PO 8 mg up to 3 times daily ½ hour before meals.
15 to 37.5 mg Dose
ADULTS and CHILDREN (> 16 yr): PO 15 to 37.5 mg as a single dose before breakfast or 2 hr after breakfast.
Interactions
Guanethidine: May decrease hypotensive effect of guanethidine. MAOIs (eg, phenelzine); furazolidone: May cause hypertensive crisis and intracranial hemorrhage. Selective serotonin reuptake inhibitors (eg, fluoxetine): Sympathomimetic effects of phentermine and risk of “serotonin syndrome” may be increased.
Lab Test Interferences None well documented.
Adverse Reactions
CARDIOVASCULAR: Regurgitant cardiac valvular disease; palpitation; tachycardia; hypertension. CNS: Overstimulation; restlessness; dizziness; insomnia; euphoria; dysphoria; tremor; headache; psychotic episodes. DERMATOLOGIC: Allergic urticaria. GI: Dry mouth; unpleasant taste; diarrhea; constipation. GU: Impotence; changes in libido. RESPIRATORY: Primary pulmonary hypertension.
Precautions
Pregnancy: Category C. Lactation: Undetermined. Children: 8 mg dose-Safety and efficacy not established in children < 12 yr. 16 mg dose-Safety and efficacy not established in children £ 16 yr. Special risk patients: Use with caution in patients with glaucoma, hypertension, and diabetes mellitus. Drug dependence: Psychological and physical dependence may occur with continued use; this class of drugs has been extensively abused. Tolerance: Tolerance to the anorectic effect usually develops within a few weeks. Primary pulmonary hypertension: Has been reported with concurrent use of phentermine and fenfluramine or dexfenfluramine. Valvular heart disease: Serious regurgitant cardiac valvular disease has been reported with concurrent use of phentermine and fenfluramine or dexfenfluramine.
PATIENT CARE CONSIDERATIONS |
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Administration/Storage
- Discontinue MAOIs ³ 14 days before initiating therapy.
- Administer 8 mg dose up to 3 times daily as prescribed, ½ hour before meals. Administer last dose several hours before bedtime.
- Administer 15 to 37.5 mg doses as a single daily dose before, or 2 hr after breakfast. Medication is slowly released over 10 to 14 hr. Swallow whole. Do not crush or chew 15 to 37.5 mg strength tablets or capsules.
- Store at controlled room temperature (59° to 86°F).
Assessment/Interventions
- Obtain patient history, including drug history and any known allergies. Note history of advanced coronary artery disease, moderate to severe hypertension, hyperthyroidism, sensitivity to sympathomimetic amines, glaucoma, agitation, history of drug abuse or concurrent or recent MAOI therapy.
- Ensure that patient receives dietary instructions regarding caloric restriction.
- Determine baseline weight. Weigh periodically to monitor response to therapy.
- Monitor blood sugar in patients with diabetes more frequently when drug is started or dose is changed.
- Monitor patient for CNS, RESP, CV, GI, and general body side effects.
OVERDOSAGE: SIGNS & SYMPTOMS |
| Restlessness, tremor, hyperreflexia, rapid respiration, confusion, assaultiveness, hallucinations, panic states, fatigue, depression, arrhythmias, hypertension, hypotension, circulatory collapse, nausea, vomiting, diarrhea, abdominal cramps, convulsions, coma, death |
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Patient/Family Education
- Explain name, dose, action, and potential side effects of drug.
- Advise patient using 8 mg dose to take up to 3 times daily as prescribed, ½ hour before meals, and to take last dose several hours before bedtime.
- Advise patient using 15 to 37.5 mg dose as a single daily dose before, or 2 hr after, breakfast. Advise patient to swallow tablet or capsule whole and to not crush or chew the tablet or capsule.
- Encourage patient to follow medically supervised weight reduction program. Emphasize that this medication will only work in conjunction with a caloric-restricted diet and exercise program.
- Advise patient that medication should be taken as prescribed and to not stop taking or change the dose unless advised to do so by health care provider.
- Explain that appetite suppressant effects are temporary and tolerance to medication and dependence can occur. Caution patient to not increase the dose in an effort to overcome the tolerance when it occurs.
- Remind patients with diabetes to monitor blood sugar more frequently while implementing dietary restrictions and to notify health care provider if significant changes in blood sugar occur.
- Caution patient that drug may impair the ability to drive or perform other tasks requiring mental alertness.
- Advise patient to notify health care provider immediately if the following symptoms occur: decreased exercise tolerance, dyspnea, swelling of the feet or ankles, fainting, chest pain, palpitations, nervousness, or dizziness.
- Advise patient to notify health care provider if experiencing any unusual or unexplained symptoms.
- Advise women to inform health care provider if they become pregnant, plan on becoming pregnant, or are breastfeeding.
- Warn patient not to take any prescription or otc drugs or dietary supplements without consulting health care provider.
- Advise patient that follow-up visits may be necessary to monitor therapy and to be sure to keep appointments.
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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts
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