Phentermine Hydrochloride


This page covers: categories, drug classes, brand names & cost of therapy, clinical pharmacology, indications and usage, contraindications, warnings, precautions, drug interactions, adverse reactions, drug abuse and dependence and more.


CATEGORIES, DRUG CLASSES, BRAND NAMES & COST OF THERAPY


CATEGORIES: Obesity, exogenous; DEA Class CIV; Pregnancy Category B; FDA Approved 1973 Aug

Drug Classes: Anorexiants; Stimulants, central nervous system

BRAND NAMES: Adipex-P; Dapex-37.5; Fastin; Obe-Nix; Oby-Cap; Oby-Trim; Ona-Mast; Panbesyl; Phentercot; Phentride; T-Diet; Teramin; Tora; Umi-Pex 30; Zantryl

FOREIGN BRAND AVAILABILITY:
Minobese-Forte (South Africa)
Panbesy (Hong Kong; Malaysia; Thailand)
Panbesyl Nyscaps (Belgium)
Redusa (Hong Kong)
Umine (New Zealand)


COST OF THERAPY:
$1.73 (Weight Loss; Generic Tablets; 30 mg; 1 capsule/day; 30 day supply)



DESCRIPTION


Each Fastin capsule contains phentermine hydrochloride, 30 mg (equivalent to 24 mg phentermine).

Phentermine hydrochloride is a white crystalline powder, very soluble in water and alcohol. Chemically, the product is phenyl-tertiary-butylamine hydrochloride. Fastin Inactive Ingredients: FD&C blue no. 1, invert sugar, methylcellulose, polyethylene glycol, starch, sucrose and titanium dioxide. The branding ink used on the gelatin capsules contains: aluminum lake, ethyl alcohol, FD&C blue no. 1 , isopropyl alcohol, n-butyl alcohol, pharmaceutical shellac (modified) or refined shellac (food grade) and propylene glycol.



CLINICAL PHARMACOLOGY


Phentermine HCl is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, the amphetamines. Actions include central nervous system stimulation and elevation of blood pressure. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Drugs of this class used in obesity are commonly known as "anorectics" or "anorexigenics." It has not been established that the action of such drugs in treating obesity is primarily one of appetite suppression. Other central nervous system actions, or metabolic effects, may be involved, for example.

Adult obese subjects instructed in dietary management and treated with "anorectic" drugs lose more weight on the average than those treated with placebo and diet, as determined in relatively short-term clinical trials.

The magnitude of increased weight loss of drug-treated patients over placebo-treated patients is only a fraction of a pound a week. The rate of weight loss is greatest in the first weeks of therapy for both drug and placebo subjects and tends to decrease in succeeding weeks. The possible origins of the increased weight loss due to the various drug effects are not established. The amount of weight loss associated with the use of an "anorectic" drug varies from trial to trial, and the increased weight loss appears to be related in part to variables other than the drugs prescribed, such as the physician-investigator, the population treated, and the diet prescribed. Studies do not permit conclusions as to the relative importance of the drug and non-drug factors on weight loss.

The natural history of obesity is measured in years, whereas the studies cited are restricted to a few weeks' duration; thus, the total impact of drug-induced weight loss over that of diet alone must be considered clinically limited.



INDICATIONS AND USAGE


Phentermine HCl is indicated as a short-term (a few weeks) adjunct in a regimen of weight reduction based on exercise, behavorial modification and caloric restriction in the management of exogenous obesity for patients with an initial body mass index ³30 kg/m2, or ³27 kg/m2 in the presence of other risk factors (e.g., hypertension, diabetes, hyperlipidemia).

The limited usefulness of agents of this class (see CLINICAL PHARMACOLOGY) should be measured against possible risk factors inherent in their use as described in WARNINGS.



CONTRAINDICATIONS



Advanced arteriosclerosis, cardiovascular disease, moderate to severe hypertension, hyperthyroidism, known hypersensitivity or idiosyncrasy to the sympathomimetic amines, glaucoma.
Agitated states.
Patients with a history of drug abuse.
During or within 14 days following the administration of monoamine oxidase inhibitors (hypertensive crises may result).



WARNINGS


Phentermine HCl capsules are indicated only as short-term monotherapy for the management of exogenous obesity. The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss, including selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. Therefore, coadministration of these drug products for weight loss is not recommended.

Primary Pulmonary Hypertension (PPH) — a rare, frequently fatal disease of the lungs — has been reported to occur in patients receiving a combination of phentermine with fenfluramine or dexfenfluramine. The possibility of an association between PPH and the use of phentermine alone cannot be ruled out; there have been rare cases of PPH in patients who reportedly have taken phentermine alone. The initial symptom of PPH is usually dyspnea. Other initial symptoms include: angina pectoris, syncope or lower extremity edema. Patients should be advised to report immediately any deterioration in exercise tolerance. Treatment should be discontinued in patients who develop new, unexplained symptoms of dyspnea, angina pectoris, syncope or lower extremity edema.


Valvular Heart Disease

Serious, regurgitant cardiac valvular disease, primarily affecting the mitral, aortic and/or tricuspid valves, has been reported in otherwise healthy persons who had taken a combination of phentermine with fenfluramine or dexfenfluramine for weight loss. The etiology of these valvulopathies has not been established and their course in individuals after the drugs are stopped is not known. The possibility of an association between valvular heart disease and the use of phentermine alone cannot be ruled out; there have been rare cases of valvular heart disease in patients who reportedly have taken phentermine alone.


Tolerance to the anorectic effect usually develops within a few weeks. When this occurs, the recommended dose should not be exceeded in an attempt to increase the effect; rather, the drug should be discontinued.

Phentermine HCl 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.

Usage With Alcohol: Concomitant use of alcohol with phentermine HCl may result in an adverse drug interaction.



PRECAUTIONS



General

Caution is to be exercised in prescribing phentermine HCl for patients with even mild hypertension.

Insulin requirements in diabetes mellitus may be altered in association with the use of phentermine HCl and the concomitant dietary regimen.

Phentermine HCl may decrease the hypotensive effect of guanethidine.

The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.



Carcinogenesis, Mutagenesis, and Impairment of Fertility

Studies have not been performed with phentermine HCl to determine the potential for carcinogenesis, mutagenesis, or impairment of fertility.



Pregnancy, Teratogenic Effects, Pregnancy Category C

Animal reproduction studies have not been conducted with phentermine HCl. It is also not known whether phentermine HCl can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Phentermine HCl should be given to a pregnant woman only if clearly needed.



Nursing Mothers

Because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.



Pediatric Use

Safety and effectiveness in pediatric patients have not been established.




DRUG INTERACTIONS


Concomitant use of alcohol with phentermine HCl may result in an adverse drug interaction.



ADVERSE REACTIONS



Cardiovascular: Primary pulmonary hypertension and/or regurgitant cardiac valvular disease (see WARNINGS), palpitation, tachycardia, elevation of blood pressure.
Central Nervous System: Overstimulation, restlessness, dizziness, insomnia, euphoria, dysphoria, tremor, headache; rarely psychotic episodes at recommended doses.
Gastrointestinal: Dryness of the mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances.
Allergic: Urticaria.
Endocrine: Impotence, changes in libido.



DRUG ABUSE AND DEPENDENCE


Phentermine HCl is related chemically and pharmacologically to the amphetamines. Amphetamines and related stimulant drugs have been extensively abused, and the possibility of abuse of phentermine HCl should be kept in mind when evaluating the desirability of including a drug as part of a weight reduction program. Abuse of amphetamines and related drugs may be associated with intense psychological dependence and severe social dysfunction. There are reports of patients who have increased the dosage to many times that recommended. Abrupt cessation following prolonged high dosage administration results in extreme fatigue and mental depression; changes are also noted on the sleep EEG. Manifestations of chronic intoxication with anorectic drugs include severe dermatoses, marked insomnia, irritability, hyperactivity, and personality changes. The most severe manifestation of chronic intoxications is psychosis, often clinically indistinguishable from schizophrenia.



OVERDOSAGE


Manifestations of acute overdosage with phentermine include restlessness, tremor, hyperreflexia, rapid respiration, confusion, assaultiveness, hallucinations, panic states. Fatigue and depression usually follow the central stimulation. Cardiovascular effects include arrhythmias, hypertension or hypotension, and circulatory collapse. Gastrointestinal symptoms include nausea, vomiting, diarrhea, and abdominal cramps. Fatal poisoning usually terminates in convulsions and coma.

Management of acute phentermine intoxication is largely symptomatic and includes lavage and sedation with a barbiturate. Experience with hemodialysis or peritoneal dialysis is inadequate to permit recommendations in this regard. Acidification of the urine increases phentermine excretion. Intravenous phentolamine has been suggested for possible acute, severe hypertension, if this complicates phentermine overdosage.



DOSAGE AND ADMINISTRATION


Exogenous Obesity: One capsule at approximately 2 hours after breakfast for appetite control. Late evening medication should be avoided because of the possibility of resulting insomnia.

Administration of 1 capsule (30 mg) daily has been found to be adequate in depression of the appetite for 12-14 hours.

Phentermine HCl is not recommended for use in patients 16 years of age and under.



HOW SUPPLIED


Blue and clear capsules with blue and white beads containing 30 mg phentermine HCl (equivalent to 24 mg phentermine) imprinted with "BEECHAM" on cap and product name "FASTIN" on body.

Storage: Store at room temperature.



PRODUCT LISTING

PRODUCT LISTING - RATED THERAPEUTICALLY EQUIVALENT Capsule, Extended Release - Oral - 15 mg
100's $125.37 Generic, Eon Labs Manufacturing Inc 00185-0644-01
1000's $1191.09 Generic, Eon Labs Manufacturing Inc 00185-0644-10
Capsule, Extended Release - Oral - 30 mg
100's $5.78 Generic, Interstate Drug Exchange Inc 00814-6077-14
100's $5.93 Generic, Interstate Drug Exchange Inc 00814-6078-14
100's $7.35 Generic, Rexar Pharmacal 00478-5469-01
100's $10.05 Generic, Aligen Independent Laboratories Inc 00405-4796-01
100's $11.96 Generic, Mutual/United Research Laboratories 00677-0460-01
100's $18.00 Generic, Watson/Rugby Laboratories Inc 00536-4236-01
100's $25.02 Generic, King Pharmaceuticals Inc 60793-0009-01
100's $31.95 Generic, Camall Company 00147-0198-10
100's $31.95 Generic, Camall Company 00147-0201-10
100's $31.95 Generic, Camall Company 00147-0202-10
100's $73.50 T-Diet, Jones Pharma Inc 52604-0010-01
100's $93.00 Zantryl, Ion Laboratories Inc 11808-0555-01
100's $96.64 Generic, Major Pharmaceuticals Inc 00904-3921-60
100's $101.00 Generic, Able Laboratories Inc 53265-0259-10
100's $103.35 Generic, Eon Labs Manufacturing Inc 00185-0647-01
100's $103.35 Generic, Mutual/United Research Laboratories 00677-1823-01
100's $130.65 Generic, Major Pharmaceuticals Inc 00904-0614-60
100's $131.98 Generic, Eon Labs Manufacturing Inc 00185-5000-01
500's $36.00 Generic, Shire Richwood Pharmaceutical Company Inc 58521-0333-05
1000's $22.00 Generic, Eon Labs Manufacturing Inc 00185-0635-10
1000's $22.00 Generic, Eon Labs Manufacturing Inc 00185-0640-10
1000's $25.90 Generic, Roberts/Hauck Pharmaceutical Corporation 43797-0378-06
1000's $40.30 Generic, Interstate Drug Exchange Inc 00814-6078-30
1000's $40.50 Generic, Rexar Pharmacal 00478-5465-10
1000's $40.50 Generic, Rexar Pharmacal 00478-5469-10
1000's $40.50 Generic, Rexar Pharmacal 00478-5474-10
1000's $42.50 Generic, Hyrex Pharmaceuticals 00314-0206-10
1000's $42.50 Generic, Rexar Pharmacal 00478-5468-10
1000's $43.80 Generic, Aligen Independent Laboratories Inc 00405-4796-03
1000's $53.90 Generic, Moore, H.L. Drug Exchange Inc 00839-5099-16
1000's $53.90 Generic, Moore, H.L. Drug Exchange Inc 00839-6298-16
1000's $124.45 Generic, Camall Company 00147-0201-20
1000's $161.95 Generic, Camall Company 00147-0198-20
1000's $161.95 Generic, Camall Company 00147-0202-20
1000's $972.00 Generic, Major Pharmaceuticals Inc 00904-3921-80
1000's $981.83 Generic, Eon Labs Manufacturing Inc 00185-0647-10
1000's $981.83 Generic, Mutual/United Research Laboratories 00677-1823-10
1000's $1240.00 Generic, Major Pharmaceuticals Inc 00904-0614-80
1000's $1253.77 Generic, Eon Labs Manufacturing Inc 00185-5000-10
Capsule, Extended Release - Oral - 37.5 mg
100's $38.95 Generic, Camall Company 00147-0234-10
100's $38.95 Generic, Camall Company 00147-0235-10
100's $38.95 Generic, Camall Company 00147-0251-10
100's $38.95 Generic, Camall Company 00147-0253-10
100's $38.95 Generic, Camall Company 00147-0254-10
100's $70.95 Generic, Camall Company 00147-0231-10
100's $85.91 Generic, Abana Pharmaceuticals 12463-0217-01
100's $157.00 Generic, Amide Pharmaceutical Inc 52152-0167-02
100's $174.76 Adipex-P, Gate Pharmaceuticals 57844-0019-01
1000's $221.95 Generic, Camall Company 00147-0234-20
1000's $221.95 Generic, Camall Company 00147-0235-20
1000's $221.95 Generic, Camall Company 00147-0251-20
1000's $221.95 Generic, Camall Company 00147-0253-20
1000's $221.95 Generic, Camall Company 00147-0254-20
1000's $584.95 Generic, Camall Company 00147-0231-20
1000's $1392.61 Generic, Amide Pharmaceutical Inc 52152-0167-05
1008's $65.02 Generic, Jones Pharma Inc 52604-9155-08
Tablet - Oral - 8 mg
100's $15.65 Generic, Camall Company 00147-0136-10
1000's $113.95 Generic, Camall Company 00147-0102-20
1000's $113.95 Generic, Camall Company 00147-0136-20
Tablet, Extended Release - Oral - 37.5 mg
100's $23.00 Generic, Ivax Corporation 00182-0205-01
100's $35.81 Generic, Pan American Laboratories 00525-0509-01
100's $39.80 Generic, Camall Company 00147-0232-10
100's $70.95 Generic, Camall Company 00147-0248-10
100's $150.00 Generic, Able Laboratories Inc 53265-0257-10
100's $152.25 Generic, Purepac Pharmaceutical Company 00228-3016-11
100's $152.25 Generic, Mutual/United Research Laboratories 00677-1824-01
100's $154.25 Generic, Amide Pharmaceutical Inc 52152-0159-02
100's $171.68 Adipex-P, Gate Pharmaceuticals 57844-0009-01
400's $532.00 Generic, Amide Pharmaceutical Inc 53265-0257-40
1000's $223.25 Generic, Ivax Corporation 00182-0205-10
1000's $525.95 Generic, Camall Company 00147-0232-20
1000's $584.95 Generic, Camall Company 00147-0248-20
1000's $1180.32 Generic, Mutual/United Research Laboratories 00677-1824-10
1000's $1311.48 Adipex-P, Gate Pharmaceuticals 57844-0009-10
1000's $1369.00 Generic, Amide Pharmaceutical Inc 52152-0159-05
1000's $1450.00 Generic, Able Laboratories Inc 53265-0257-11
1000's $1492.05 Generic, Purepac Pharmaceutical Company 00228-3016-96
1008's $67.54 Generic, Jones Pharma Inc 52604-9156-08

PRODUCT LISTING - EQUIVALENTS NOT AVAILABLE Capsule, Extended Release - Oral - Resin 15 mg
100's $106.25 Ionamin, Celltech Pharmacueticals Inc 00585-0903-71
100's $232.80 Ionamin, Celltech Pharmacueticals Inc 53014-0903-71
400's $888.38 Ionamin, Celltech Pharmacueticals Inc 53014-0903-84
Capsule, Extended Release - Oral - Resin 30 mg
100's $266.68 Ionamin, Celltech Pharmacueticals Inc 53014-0904-71
400's $446.36 Ionamin, Celltech Pharmacueticals Inc 00585-0904-84
400's $1018.09 Ionamin, Celltech Pharmacueticals Inc 53014-0904-84
Capsule, Extended Release - Oral - 15 mg
6's $17.10 Generic, Pharma Pac 52959-0426-06
7's $19.51 Generic, Pharma Pac 52959-0426-07
14's $24.91 Generic, Pharma Pac 52959-0426-14
15's $26.11 Generic, Pharma Pac 52959-0426-15
24's $30.31 Generic, Pharma Pac 52959-0426-24
28's $35.35 Generic, Pharma Pac 52959-0426-28
30's $38.11 Generic, Pharma Pac 52959-0426-30
Capsule, Extended Release - Oral - 18.75 mg
7's $3.35 Generic, Allscripts Pharmaceutical Company 54569-2669-00
15's $7.18 Generic, Allscripts Pharmaceutical Company 54569-2669-01
21's $10.05 Generic, Allscripts Pharmaceutical Company 54569-2669-03
30's $14.35 Generic, Allscripts Pharmaceutical Company 54569-2669-02
100's $30.95 Generic, Camall Company 00147-0249-10
100's $66.84 Generic, Mcr/American Pharmaceuticals Inc 58605-0508-01
1000's $30.00 Generic, C.O. Truxton Inc 00463-3036-10
1000's $131.95 Generic, Camall Company 00147-0249-20
Capsule, Extended Release - Oral - 30 mg
7's $8.47 Generic, Pharma Pac 52959-0440-07
14's $4.45 Generic, Southwood Pharmaceuticals Inc 58016-0861-14
15's $18.15 Generic, Pharma Pac 52959-0440-15
30's $5.81 Generic, Southwood Pharmaceuticals Inc 58016-0861-30
30's $36.30 Generic, Pharma Pac 52959-0440-30
60's $10.28 Generic, Southwood Pharmaceuticals Inc 58016-0861-60
1008's $51.75 Generic, Jones Pharma Inc 52604-9153-08
1008's $60.58 Generic, Jones Pharma Inc 52604-9151-08
1008's $60.58 Generic, Jones Pharma Inc 52604-9152-08
Capsule, Extended Release - Oral - 37.5 mg
100's $52.89 Generic, Mcr/American Pharmaceuticals Inc 58605-0503-01
Tablet - Oral - 8 mg
100's $54.07 Generic, Mcr/American Pharmaceuticals Inc 58605-0504-01
1000's $59.95 Generic, Legere Pharmaceuticals 25332-1113-01
Tablet, Extended Release - Oral - 37.5 mg
100's $152.25 Generic, Qualitest Products Inc 00603-5192-21
1000's $1446.38 Generic, Qualitest Products Inc 00603-5192-32

The information on this page is from a drug guide that can be found at us.elsevierhealth.com and be bought directly from them. Search "drug guide" when you arrive at their site.