Names and pronunciation
(dox′e-pin) Sineguan , Silenor
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Drug reference
(dox′e-pin) Sineguan , Silenor
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Func. class.: Antidepressant, tricyclic, antihistamine (topical)
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Chem. class.: Dibenzoxepine, tertiary amine
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Do not confuse: Sinequan/Seroquel/Saquinavir/Singulair/ Zonegran
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ACTION: Blocks reuptake of norepi- nephrine, serotonin into nerve endings, increasing action of norepinephrine, serotonin in nerve cells
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USES: Major depression, anxiety; topical: lichen simplex, atopic dermati- tis, eczema, insomnia, migraine prophylaxis
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Unlabeled uses: Topical pruritus C O N T R A I N D I C AT I O N S : Hypersensitivity to tricyclics, urinary retention, closed-angle glaucoma, pros- tatic hypertrophy, acute recovery from MI Precautions: Pregnancy, breastfeeding, geriatric patients, seizures
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Black Box Warning: Children, suicidal patients
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SIDE EFFECTS CNS: Dizziness, drowsiness, confusion, headache, anxiety, tremors, stimulation, weakness, insomnia, nightmares, EPS (geriatric patients), increased psychiatric symptoms, paresthesia, suicidal ideation CV: Orthostatic hypotension, ECG changes, tachycardia, hypertension, palpitations, dysrhythmias EENT: Blurred vision, tinnitus, mydria- sis, ophthalmoplegia, glossitis GI: Diarrhea, dry mouth, nausea, vom- iting, paralytic ileus, increased appetite, cramps, epigastric distress, jaundice, hepatitis, stomatitis, constipation GU: Urinary retention, acute renal failure HEMA: Agranulocytosis, thrombocytope- nia, eosinophilia, leukopenia, pancytope- nia, purpuric disorder INTEG: Rash, urticaria, sweating, pruri- tus, photosensitivity
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INTERACTIONS Increase: hyperpyretic crisis, seizures, hypertensive episode—MAOIs Increase: hypertensive action—EPI- NEPHrine, norepinephrine Increase: hypertensive crisis—cloNI- Dine; do not use together Increase: doxepin effect—cimetidine, FLUoxetine, fluvoxaMINE, PARoxetine, sertraline Increase: CNS depression—barbiturates, benzodiazepines, sedative/hypnotics, alco hol, other CNS depressants Increase: QT interval—class IC/III antiar- rhythmics (propafenone, flecainide), qui nolones Increase: serotonin syndrome, toxicity— SSRIs, SNRIs, serotonin-receptor agonists, triptans Increase: anticholinergic effects— anticholinergics Drug/Herb • Serotonin syndrome: St. John’s wort; avoid using together Drug/Lab Test Increase: serum bilirubin, blood glu- cose, alkaline phosphatase, LFTs
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TREATMENT OF OVERDOSE: ECG monitoring; lavage, administer anti- convulsant, sodium bicarbonate HIGH ALERT
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DOSAGE AND ROUTES Depression/anxiety • Adult: PO 50-75 mg/day, may increase to 300 mg/day for severely ill; give in di- vided doses if >150 mg/day • Geriatric: PO 25-50 mg at bedtime, increase weekly by 25-50 mg to desired dose, max 150 mg/day Pruritus • Adult: PO 10 mg at bedtime, may in- crease to 25 mg at bedtime; TOPICAL apply thin film qid at least 3 hr apart Insomnia (Silenor) • Adult: PO 6 mg 30 min prior to bedtime, 3 mg may be sufficient, max 6 mg/night
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Available forms: Capsules 10, 25, 50, 75, 100, 150 mg; oral concentrations 10 mg/mL; tablets (Silenor) 3, 6 mg
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Administer: • Oral concentrations: should be di- luted with 120 mL water, milk, or orange, grapefruit, tomato, prune, or pineapple juice; do not mix with grape juice • Increased fluids, bulk in diet for con- stipation • With food, milk for GI symptoms; do not give with carbonated beverages • Dosage at bedtime to avoid overseda- tion during day; may take entire dose at bedtime; geriatric patients may not toler- ate daily dosing • Gum, hard candy, or frequent sips of water for dry mouth • Store in tight container protected from direct sunlight
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Assess: • B/P (lying, standing), pulse q4hr; if systolic B/P drops 20 mm Hg, hold product, notify prescriber; VS q4hr in patients with CV disease • Blood studies: CBC, leukocytes, dif- ferential, cardiac enzymes if patient is receiving long-term therapy • Hepatic studies: AST, ALT, bilirubin • Weight weekly; appetite may increase with product • ECG for flattening of T wave, bundle branch block, AV block, dysrhythmias in car- diac patients; product should be discontin- ued gradually several days prior to surgery • EPS primarily in geriatric patients: ri- gidity, dystonia, akathisia • Depression: mood, sensorium, affect, suicidal tendencies, increase in psychiat- ric symptoms; assess often during initial treatment; restrict the amount of the product given to the patient • Chronic pain: location, severity, type prior to and during treatment, alleviat- ing/aggravating factors • Sexual dysfunction: decreased libido and erectile dysfunction may occur • Urinary retention, constipation; con- stipation most likely in children, geriatric patients • Withdrawal symptoms: headache, nausea, vomiting, muscle pain, weak- ness; not usual unless product is discon- tinued abruptly D • Alcohol consumption; if alcohol is consumed, hold dose until morning • Assistance with ambulation during be- ginning therapy because drowsiness/diz- ziness occurs; safety measures primarily for geriatric patients • Serotonin syndrome: nausea, vomiting, diarrhea, agitation, halluci- nations, hyperthermia, incoordination; may occur when used with other prod- ucts known to cause serotonin syn- drome • Beers: avoid use in older adults; highly anticholinergic, sedating; causes orthostatic hypotension, may cause delirium • Pregnancy/breastfeeding: no well- controlled studies; use only if benefit outweighs fetal risk; use caution in breastfeeding, excreted in breast milk
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Evaluate: • Therapeutic response: decreased anxiety, depression
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • That therapeutic effect (depression) may take 2-3 wk, antianxiety effects sooner • To use caution when driving, during other activities requiring alertness because of drowsiness, dizziness, blurred vision • To avoid alcohol, other CNS depressants; may potentiate effects; not to take other products unless approved by prescriber • Not to discontinue medication abruptly after long-term use; may cause nausea, headache, malaise • To wear sunscreen or large hat; pho- tosensitivity occurs • That clinical worsening and suicide may occur, usually in children, young adults ≤24 yr • To immediately report urinary retention
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PHARMACOKINETICS PO: Peak 2 hr, metabolized in liver by CYP2C19/CYP2D6, which exert genetic polymorphism; Asians, Black patients may be poor metabolizers; excreted by kidneys, crosses placenta, excreted in breast milk, half-life 8-24 hr
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• Adult: PO 50-75 mg/day, may increase to 300 mg/day for severely ill; give in di- vided doses if >150 mg/day
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• Adult: PO 10 mg at bedtime, may in- crease to 25 mg at bedtime; TOPICAL apply thin film qid at least 3 hr apart Insomnia (Silenor)
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• Adult: PO 6 mg 30 min prior to bedtime, 3 mg may be sufficient, max 6 mg/night
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