Mosby's 2014 Nursing Drug Reference (379 page)

BOOK: Mosby's 2014 Nursing Drug Reference
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Canada only   Side effects:
italics
= common;
bold
= life-threatening   
Nurse Alert

tadalafil (Rx)

(tah-dal′a-fil)

Adcirca, Cialis

Func. class.:
Impotence agent

Chem. class.:
Phosphodiesterase type 5 inhibitor

ACTION:

Inhibits phosphodiesterase type 5 (PDE5); enhances erectile function by increasing the amount of cGMP, which causes smooth muscle relaxation and increased blood flow into the corpus cavernosum; improves erectile function for up to 36 hr

USES:

Treatment of erectile dysfunction, benign prostatic hyperplasia (BPH) with or without erectile dysfunction pulmonary arterial hypertension (PAH) (Adcirca only)

Unlabeled uses:
Sexual dysfunction in males receiving antidepressants

CONTRAINDICATIONS:

Newborns, children, women, hypersensitivity, patients taking organic nitrates either regularly and/or intermittently, patients taking any α-adrenergic antagonist other than 0.4 mg once-daily tamsulosin

Precautions:
Pregnancy (B) although not indicated for females, anatomic penile deformities, sickle cell anemia, leukemia, multiple myeloma, CV/renal/hepatic disease, bleeding disorders, active peptic ulcer, prolonged erection

DOSAGE AND ROUTES
Calculator
Erectile dysfunction

• Adult:
PO
(Cialis) 10 mg taken before sexual activity, dose may be reduced to 5 mg or increased to max 20 mg; usual max dosing frequency is 1×/day; once-daily dosing 2.5 mg/day at same time each day

BPH

• Adult:
PO
5 mg bid at the same time every day

Renal dose

• Adult:
PO
CCr 51-80 ml/min: no adjustment for erectile dysfunction, 20 mg/day initially for pulmonary hypertension; CCr 31-50 ml/min, 5 mg/day, max 10 mg q48hr; CCr <30 ml/min, max 5 mg q72hr

Hepatic dose

• Adult:
PO
(Child-Pugh A, B) max 10 mg/day or 20 mg/day, (pulmonary hypertension) max 40 mg/day; (Child-Pugh C) not recommended

Concomitant medications

• 
Ketoconazole, itraconazole, ritonavir, max 10 mg q72hr

Pulmonary hypertension

• Adult:
PO (Adcirca only)
40 mg daily

• Adult taking ritonavir:
PO
20 mg daily initially then increase to 40 mg daily as tolerated

Male sexual dysfunction (from antidepressants) (unlabeled)

• Adult:
PO
(Cialis) 10-20 mg before sexual activity

Available forms:
Tabs 2.5, 5, 10, 20 mg; PO tab (Adcirca) 20 mg

Administer:

• 
Product should not be used with nitrates in any form

• 
Sexual dysfunction:
give before sexual activity; do not use more than 1×/day

• 
Pulmonary hypertension:
give Adcirca with/without meals

SIDE EFFECTS

CNS:
Headache, flushing, dizziness
,
seizures,
transient global amnesia

CV:
Hypotension,
QT prolongation

INTEG:
Stevens-Johnson syndrome, exfoliative dermatitis,
urticaria

MISC:
Back pain/myalgia,
dyspepsia, nasal congestion, UTI
, blurred vision, changes in color vision,
diarrhea
, pruritus, priapism,
nonarteritic ischemic optic neuropathy (NAION),
hearing loss

PHARMACOKINETICS

Rapidly absorbed; metabolized by liver by CYP3A4; terminal half-life 17.5 hr; peak 1/2-6 hr; excreted primarily as metabolites in feces, urine; excreted 61% in feces, 36% in urine; 94% protein bound; rate and extent of absorption not influenced by food

INTERACTIONS

 
Do not use with nitrates because of unsafe drop in B/P, which could result in MI or stroke

Increase:
tadalafil levels—itraconazole, ketoconazole, ritonavir (although not studied, may also include other HIV protease inhibitors)

Decrease:
B/P—alcohol, α-blockers, amLODIPine, angiotensin II receptor blockers, enalapril

Decrease:
effects of tadalafil—bosentan, antacids

Drug/Food

Increase:
tadalafil effect—grapefruit

NURSING CONSIDERATIONS
Assess:

• 
Cialis:
underlying cause of erectile dysfunction before treatment; use of organic nitrates that should not be used with this product; any severe loss of vision while taking this or any similar products

• 
Adcirca:
hemodynamic parameters at baseline and periodically

Evaluate:

• 
Therapeutic response: ability to engage in sexual intercourse, improvement in exercise ability in pulmonary hypertension

Teach patient/family:

• 
To take 1 hr before sexual activity

• 
Not to drink large amounts of alcohol

• 
That product does not protect against sexually transmitted diseases, including HIV

• 
That product has no effect in the absence of sexual stimulation; to seek medical help if erection lasts >4 hr

• 
To tell physician about all medicines, vitamins, herbs being taken, especially ritonavir, indinavir, ketoconozole, itraconazole, erythromycin, nitrates, α-blockers; that tadalafil is contraindicated for use with α-blockers except 0.4 mg/day tamsulosin

 
To notify prescriber immediately and to stop taking product if vision, hearing loss occur or if erection lasts >4 hr or if chest pain occurs

Canada only   Side effects:
italics
= common;
bold
= life-threatening   
Nurse Alert

tamoxifen (Rx)

(ta-mox′i-fen)

Apo-Tamox
, Nolvadex
, Tamofen

Func. class.:
Antineoplastic

Chem. class.:
Antiestrogen hormone

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