Nefazodone Hydrochloride

Pronunciation

Pronunciation: neff-AZE-oh-dohn HIGH-droe-KLOR-ide
Class: Antidepressant

Trade Names

Nefazodone Hydrochloride
- Tablets 50 mg
- Tablets 100 mg
- Tablets 150 mg
- Tablets 200 mg
- Tablets 250 mg

Pharmacology

Undetermined; inhibits neuronal uptake of serotonin and norepinephrine; antagonizes alpha-1 adrenergic receptors.

Slideshow: How to Manage Antidepressant Side Effects

Pharmacokinetics

Absorption

Absorption is rapid and complete. Absolute bioavailability is approximately 20%, T max is about 1 h, and steady state is 4 to 5 days (parent and metabolite). Food delays absorption and decreases bioavailability.

Distribution

Nefazodone is widely distributed in body tissues, including CNS, and exhibits nonlinear kinetics for dose and time. Nefazodone Vd is 0.22 to 0.87 L/kg and plasma protein binding is more than 99%.

Metabolism

Nefazodone is extensively metabolized in the liver by n-dealkylation and aliphatic and aromatic hydroxylation. Three active metabolites are hydroxynefazodone (HO-NEF), meta-chlorophenylpiperazine (mCPP), and triazole-dione.

Elimination

Nefazodone is eliminated in urine (less than 1% excreted as unchanged) and feces. The t ½ is 2 to 4 h (parent compound), 1.5 to 4 h (HO-NEF), 4 to 8 h (mCPP), and 18 h (triazole-dione).

Special Populations

Elderly

C max and AUC for nefazodone and HO-NEF were twice as high. Initiate at half the dose, especially in elderly women.

Gender

Nefazodone has a higher C max and AUC in women in single dose, but no difference after multiple doses.

Liver Cirrhosis

AUC for nefazodone and HO-NEF at steady state were approximately 25% greater.

Indications and Usage

Treatment of depression.

Contraindications

Coadministration with carbamazepine, cisapride, or pimozide; hypersensitivity to nefazodone or other phenylpiperazine antidepressants (eg, trazodone).

Dosage and Administration

Adults

PO 100 mg twice daily initially; increase by 100 to 200 mg increments every wk (max, 600 mg/day).

Elderly and Debilitated Patients

PO 50 mg twice daily initially; increase by 100 mg increments every wk (max, 600 mg/day).

General Advice

  • Administer without regard to meals. Administer with food if GI upset occurs.

Storage/Stability

Store tablets at controlled room temperature (59° to 86°F).

Drug Interactions

Benzodiazepines

Increased plasma concentrations and effects of alprazolam and triazolam.

Buspirone

Elevated buspirone concentrations and decreased buspirone metabolite plasma concentrations.

Carbamazepine

Elevated serum carbamazepine concentrations with possible increase in adverse reactions may occur.

Cisapride

Increased cisapride plasma concentrations with cardiotoxicity may occur.

Digoxin

Increased plasma levels of digoxin.

Haloperidol

Decreased haloperidol Cl; may need to adjust haloperidol dose.

HMG-CoA reductase inhibitors (eg, simvastatin)

The risk of rhabdomyolysis occurrence may be increased.

MAOIs

Do not use nefazodone concurrently or within 14 days of discontinuing an MAOI; do not start MAOIs within 1 wk of stopping nefazodone.

Pimozide

Increased plasma concentrations of pimozide may occur associated with QT prolongation and rare cases of serious CV adverse reactions, including death, principally caused by ventricular tachycardia of the torsades de pointes type.

Propranolol

Nefazodone may decrease propranolol serum concentration; propranolol may interfere with nefazodone metabolism.

St. John's wort

Increased sedative-hypnotic effects may occur.

Sibutramine, sumatriptan, trazodone

Serotonin syndrome, including irritability, increased muscle tone, shivering, myoclonus, and altered consciousness may occur.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Postural hypotension, vasodilation (4%); hypotension (2%); sinus bradycardia (1.5%).

CNS

Headache (36%); somnolence (28%); dizziness (22%); asthenia, insomnia (11%); lightheadedness (10%); confusion (8%); memory impairment, paresthesia (4%); abnormal dreams, decreased concentration (3%); ataxia, incoordination, psychomotor retardation, tremor (2%); hypertonia, decreased libido (1%); convulsions (postmarketing).

Dermatologic

Pruritus, rash (2%); Stevens-Johnson syndrome (postmarketing).

EENT

Abnormal vision (10%); blurred vision (9%); pharyngitis (6%); tinnitus (3%); taste perversion, visual field defect (2%).

GI

Dry mouth (25%); nausea (23%); constipation (17%); dyspepsia (9%); diarrhea (8%); increased appetite (5%); nausea and vomiting (2%); gastroenteritis (at least 1%).

Genitourinary

Urinary frequency, UTI, urinary retention, vaginitis (2%); breast pain (1%); impotence (at least 1%); gynecomastia (male), priapism (postmarketing).

Hematologic

Thrombocytopenia (postmarketing).

Hepatic

Liver necrosis, liver failure (postmarketing).

Lab Tests

Decreased hematocrit (3%).

Metabolic

Peripheral edema (3%); thirst (1%); galactorrhea, hyponatremia, increased prolactin (postmarketing).

Musculoskeletal

Arthralgia (1%).

Respiratory

Increased cough (3%); dyspnea, bronchitis (at least 1%).

Miscellaneous

Infection (8%); flu-like syndrome (3%); chills, fever (2%); neck rigidity (1%); anaphylactic reactions, angioedema, serotonin syndrome (postmarketing).

Precautions

Warnings

Life-threatening cases of hepatic failure have been reported. Counsel patient about and immediately report signs of liver dysfunction. Do not initiate therapy in patients with active liver disease or elevated baseline serum transaminases. There is no evidence that preexisting liver disease increases risk of liver failure, but it can complicate patient monitoring. Withdraw therapy and do not consider retreatment if serum AST or ALT is 3 times ULN or more.


Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Elderly

Initiate treatment at half the usual dose. Dosage range same as younger patients.

Bradycardia

Sinus bradycardia reported in 1.5% of patients; use with caution in patients with recent MI or unstable heart disease.

Mania/Hypomania

May activate mania/hypomania; use with caution in patients with history of mania.

Postural hypotension

Use with caution in patients with known CV or cerebrovascular disease that could be exacerbated by hypotension (eg, history of MI, angina, ischemic stroke) and conditions that would predispose to hypotension (eg, dehydration, hypovolemia, treatment with antihypertensive medications).

Priapism

Priapism (eg, prolonged, painful, inappropriate penile erection) has been reported with closely related antidepressants. Discontinuation of therapy is necessary.

Seizures

Rare cases of petit mal and grand mal seizures reported.

Suicide

Closely monitor patients at risk, and do not give them access to excessive quantities.

Visual disturbances

Visual disturbances, including blurred vision, scotoma, and visual trails reported.

Overdosage

Symptoms

Nausea, vomiting, somnolence.

Patient Information

  • Advise patient to read the patient information leaflet before starting therapy and with each refill.
  • Advise patient that medication will be started at a low dose and then gradually increased as tolerated until max benefit is obtained.
  • Advise patient to take prescribed dose twice daily without regard to meals but to take with food if stomach upset occurs.
  • Advise patient that if a dose is missed to skip that dose and take the next dose at the regularly scheduled time. Caution patient to never take 2 doses at the same time.
  • Advise patient not to change the dose or stop taking unless advised by health care provider.
  • Inform patient that it may take 1 to 4 wk to note improvement in symptoms and to continue with the prescribed therapy once improvement has been noted.
  • Advise patient to take frequent sips of water, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
  • Advise patient to avoid alcoholic beverages.
  • Advise patient that drug may cause drowsiness or impair judgment, thinking, or reflexes and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Advise patient to immediately report any of the following to health care provider: nausea, vomiting, abdominal pain, fatigue, anorexia, dark urine, yellowing of the skin or eyes, seizure, or fainting.
  • Advise patient to contact health care provider if rash, hives, or other symptoms of an allergic reaction develop, if a painful or prolonged erection occurs, or if experiencing bothersome adverse reactions such as visual disturbances, headache, insomnia, or drowsiness.

Copyright © 2009 Wolters Kluwer Health.

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