Propoxyphene
Pronunciation
(proe POKS i feen)
U.S. Brand Names
Darvon®; Darvon-N®
Synonyms
Dextropropoxyphene; Propoxyphene Hydrochloride; Propoxyphene Napsylate
Generic Available
Yes: Capsule
Canadian Brand Names
Darvon-N®; 642® Tablet
Use
Management of mild to moderate pain
Restrictions
C-IV
Pregnancy Risk Factor
C/D (prolonged use)
Pregnancy Implications
Withdrawal symptoms have been reported in the neonate following propoxyphene use during pregnancy. Teratogenic effects have also been noted in case reports. Opioid analgesics are considered pregnancy risk factor D if used for prolonged periods or in large doses near term.
Lactation
Enters breast milk/use caution (AAP rates "compatible")
Contraindications
Hypersensitivity to propoxyphene or any component of the formulation
Warnings/Precautions
When given in excessive doses, either alone or in combination with other CNS depressants, propoxyphene is a major cause of drug-related deaths; do not exceed recommended dosage; give with caution in patients dependent on opiates, substitution may result in acute opiate withdrawal symptoms. Avoid use in severely depressed or suicidal patients. Tolerance or drug dependence may result from extended use. Propoxyphene should be used with caution in patients with renal or hepatic dysfunction or in the elderly; consider dosing adjustment.
Adverse Reactions
Frequency not defined.
Cardiovascular: Hypotension, bundle branch block
Central nervous system: Dizziness, lightheadedness, sedation, paradoxical excitement and insomnia, fatigue, drowsiness, mental depression, hallucinations, paradoxical CNS stimulation, increased intracranial pressure, nervousness, headache, restlessness, malaise, confusion, dysphoria, vertigo
Dermatologic: Rash, urticaria
Endocrine & metabolic: Hypoglycemia, urinary 17-OHCS decreased
Gastrointestinal: Anorexia, stomach cramps, xerostomia, biliary spasm, nausea, vomiting, constipation, paralytic ileus, abdominal pain
Genitourinary: Urination decreased, ureteral spasms
Hepatic: LFTs increased, jaundice
Neuromuscular & skeletal: Weakness
Ocular: Visual disturbances
Respiratory: Dyspnea
Miscellaneous: Psychologic and physical dependence with prolonged use, histamine release, hypersensitivity reaction
Overdosage/Toxicology
Symptoms of overdose include CNS disturbances, respiratory depression, hypotension, pulmonary edema, and seizures. Naloxone, 2 mg I.V. with repeat administration as necessary up to a total of 10 mg, can also be used to reverse toxic effects of the opiate. Charcoal is very effective (>95%) at binding propoxyphene.
Drug Interactions
Inhibits
CYP2C8/9 (weak), 2D6 (weak), 3A4 (weak)
Decreased effect with charcoal, cigarette smoking
Increased toxicity: CNS depressants may potentiate pharmacologic effects; propoxyphene may inhibit the metabolism and increase the serum concentrations of carbamazepine, phenobarbital, MAO inhibitors, tricyclic antidepressants, and warfarin
Ethanol/Nutrition/Herb Interactions
Ethanol: Avoid or limit ethanol (may increase CNS depression). Watch for sedation.
Food: May decrease rate of absorption, but may slightly increase bioavailability.
Stability
Store at controlled room temperature of 15°C to 30°C (59°F to 86°F).
Mechanism of Action
Propoxyphene is a weak narcotic analgesic which acts through binding to opiate receptors to inhibit ascending pain pathways. Propoxyphene, as with other narcotic (opiate) analgesics, blocks pain perception in the cerebral cortex by binding to specific receptor molecules (opiate receptors) within the neuronal membranes of synapses. This binding results in a decreased synaptic chemical transmission throughout the CNS thus inhibiting the flow of pain sensations into the higher centers. Mu and kappa are the two subtypes of the opiate receptor which propoxyphene binds to to cause analgesia.
Pharmacodynamics/Kinetics
Onset of action: 0.5-1 hour
Duration: 4-6 hours
Metabolism: Hepatic to active metabolite (norpropoxyphene) and inactive metabolites; first-pass effect
Half-life elimination: Adults: Parent drug: 6-12 hours; Norpropoxyphene: 30-36 hours
Excretion: Urine (primarily as metabolites)
Dosage
Oral:
Children: Doses for children are not well established; doses of the hydrochloride of 2-3 mg/kg/d divided every 6 hours have been used
Adults:
Hydrochloride: 65 mg every 3-4 hours as needed for pain; maximum: 390 mg/day
Napsylate: 100 mg every 4 hours as needed for pain; maximum: 600 mg/day
Elderly:
Hydrochloride: 65 mg every 4-6 hours as needed for pain
Napsylate: 100 mg every 4-6 hours as needed for pain
Dosing adjustment in renal impairment:
Serum concentrations of propoxyphene may be increased or elimination may be delayed. Avoid use in Clcr<10 mL/minute. Specific dosing recommendations not available for less severe impairment.
Not dialyzable (0% to 5%)
Dosing adjustment in hepatic impairment:
Serum concentrations of propoxyphene may be increased or elimination may be delayed; specific dosing recommendations not available.
Administration
Should be administered with glass of water on an empty stomach. Food may decrease rate of absorption, but may slightly increase bioavailability.
Monitoring Parameters
Pain relief, respiratory and mental status, blood pressure
Reference Range
Therapeutic: Ranges published vary between laboratories and may not correlate with clinical effect
Therapeutic concentration: 0.1-0.4 mcg/mL (SI: 0.3-1.2
mol/L)
Toxic: >0.5 mcg/mL (SI: >1.5
mol/L)
Test Interactions
False-positive methadone test
Dietary Considerations
May administer with food if gastrointestinal distress occurs.
Patient Education
Take as directed; do not take a larger dose or more often than prescribed. Do not use alcohol, other prescription or OTC sedatives, tranquilizers, antihistamines, or pain medications without consulting prescriber. May cause dizziness, drowsiness, or impaired judgment; avoid driving or engaging in tasks requiring alertness until response to drug is known. If you experience vomiting or loss of appetite, frequent mouth care, small, frequent meals, chewing gum, or sucking lozenges may help. Increased fluid intake, exercise, fiber in diet may help with constipation (if unresolved consult prescriber). Report unresolved nausea or vomiting, respiratory difficulty or shortness of breath, or unusual weakness.
Pregnancy/breast-feeding precautions:
Inform prescriber if you are or intend to become pregnant.
Nursing Implications
Monitor pain relief, respiratory and mental status, blood pressure, excessive sedation
Additional Information
100 mg of napsylate = 65 mg of hydrochloride
Propoxyphene hydrochloride: Darvon®
Propoxyphene napsylate: Darvon-N®
Anesthesia and Critical Care Concerns/Other Considerations
Equivalent dosing: 100 mg of napsylate = 65 mg of hydrochloride
Dental Health: Effects on Dental Treatment
Key adverse event(s) related to dental treatment: Xerostomia (normal salivary flow resumes upon discontinuation).
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
Dizziness, drowsiness, insomnia, and paradoxical excitement are common; may cause nervousness, restlessness, confusion; may rarely cause depression or hallucinations
Mental Health: Effects on Psychiatric Treatment
Concurrent use with psychotropics may produce additive sedation as well as increase their serum levels; monitor for altered clinical response or preferably, use a different analgesic
Dosage Forms
Capsule, as hydrochloride (Darvon®): 65 mg
Tablet, as napsylate (Darvon-N®): 100 mg
References
"American Academy of Pediatrics Committee on Drugs. The Transfer of Drugs and Other Chemicals Into Human Milk,"
Pediatrics
, 2001, 108(3):776-89.
"Drugs for Pain,"
Med Lett Drugs Ther
, 2000, 42(1085):73-8.
Ferrell BA, "Pain Management in Elderly People,"
J Am Geriatr Soc
, 1991, 39(1):64-73.
Finkle BS, "Self-Poisoning With Dextropropoxyphene and Dextropropoxyphene Compounds: The USA Experience,"
Hum Toxicol
, 1984, 3(Suppl):115-34.
Hasday JD and Weintraub M, "Propoxyphene in Children With Iatrogenic Morphine Dependence,"
Am J Dis Child
, 1983, 137(8):745-8.
Lawson AA and Northridge DB, "Dextropropoxyphene Overdose. Epidemiology, Clinical Presentation, and Management,"
Med Toxicol Adverse Drug Exp
, 1987, 2(6):430-44.
Miller RR, "Propoxyphene: A Review,"
Am J Hosp Pharm
, 1977, 34(4):413-23.
Mokhlesi B, Leikin JB, Murray P, et al, "Adult Toxicology in Critical Care: Part II: Specific Poisonings,"
Chest
, 2003, 123(3):897-922.
Proudfoot AT, "Clinical Features and Management of Distalgesic Overdose,"
Hum Toxicol
, 1984, 3(Suppl):85-94.
Rathmell JP, Viscomi CM, and Ashburn MA, "Management of Nonobstetric Pain During Pregnancy and Lactation,"
Anesth Analg
, 1997, 85(5):1074-87.
Stork CM, Redd JT, Fine K, et al, "Propoxyphene-Induced Wide QRS Complex Dysrhythmia Responsive to Sodium Bicarbonate - A Case Report,"
J Toxicol Clin Toxicol
, 1995, 33(2):179-83.
Tennant FS Jr, "Complications of Propoxyphene Abuse,"
Arch Intern Med
, 1973, 132(2):191-4.
Wetli CV and Bednarczyk LR, "Deaths Related to Propoxyphene Overdose: A Ten Year Assessment,"
South Med J
, 1980, 73(9):1205-9.
International Brand Names
Abalgin® (DK, FI); Acrogesico® (EC); Darvon® (ES); Darvon-N® (CA); Darvon N® (RO); Deprancol® (ES); Depronal® (BE, LU, NL); Dexofen® (SE); Dextropropoxifen "Dak"® (DK); Dextropropoxifeno Bouzen® (AR); Distalgesic® (IE, SE); Doloxene® (AU, DK, GB, IE, NZ, SE, ZA); Lentadol® (AR); Liberen® (IT); Parvodex® (IN); Proxifen® (EC); Romidon® (GR); 642® Tablet (CA); Zideron® (GR)
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