Mosby's 2014 Nursing Drug Reference (352 page)

BOOK: Mosby's 2014 Nursing Drug Reference
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rifapentine (Rx)

(riff′ah-pen-teen)

Priftin

Func. class.:
Antitubercular

Chem. class.:
Rifamycin derivative

ACTION:

Inhibits DNA-dependent polymerase, decreases tubercle bacilli replication

USES:

Pulmonary TB; must be used with at least one other antitubercular agent

CONTRAINDICATIONS:

Hypersensitivity to rifamycins, porphyria

Precautions:
Pregnancy (C), breastfeeding, children <12 yr, geriatric patients, hepatic disease, blood dyscrasias, HIV

DOSAGE AND ROUTES
Calculator
Intensive phase

• Adult:
PO
600 mg (four 150-mg tabs) 2×/wk with an interval of 72 hr between doses × 2 mo; must be given with at least 1 other antitubercular agent

Continuation phase

• Adult:
PO
600 mg q wk × 4 mo in combination with isoniazid or other appropriate antitubercular product

Available forms:
Tabs 150 mg

Administer:

• 
May give with food for GI upset, use other products for TB

• 
Antiemetic if vomiting occurs

• 
After C&S completed; monthly to detect resistance

SIDE EFFECTS

CNS:
Headache, fatigue, anxiety, dizziness

EENT:
Visual disturbances

GI:
Nausea, vomiting, anorexia, diarrhea
, bilirubinemia, hepatitis, increased ALT, AST,
heartburn
,
pancreatitis, pseudomembranous colitis

GU:
Hematuria,
pyuria, proteinuria, urinary casts, urine discoloration

HEMA:
Thrombocytopenia, leukopenia, neutropenia, lymphopenia,
anemia,
leukocytosis,
purpura, hematoma

INTEG:
Rash, pruritus, urticaria, acne

MISC:
Increased B/P

MS:
Gout, arthrosis

PHARMACOKINETICS

Peak 5-6 hr; half-life 13 hr; metabolized in liver (active/inactive metabolites); excreted in urine, feces, breast milk; protein binding 97%; steady state 10 days; CYP450 3A4, 2C8/9 inducer

INTERACTIONS

 
Do not use with protease inhibitors

Decrease:
action of amitriptyline, anticoagulants, antidiabetics, barbiturates, β-blockers, chloramphenicol, clarithromycin, clofibrate, corticosteroids, cycloSPORINE, dapsone, delavirdine, diazepam, digoxin, diltiazem, disopyramide, doxycycline, fentaNYL, fluconazole, haloperidol, indinavir, itraconazole, ketoconazole, methadone, mexiletine, nelfinavir, NIFEdipine, nortriptyline, oral contraceptives, phenothiazines, phenytoin, progestins, quiNIDine, quiNINE, ritonavir, saquinavir, sildenafil, tacrolimus, theophylline, thyroid preparations, tocainide, verapamil, warfarin, zidovudine

Drug/Food

Increase:
absorption with food

Drug/Lab Test

Increase:
LFTs, platelets

Decrease:
Hgb, WBC

Interference:
folate level, vit B
12

NURSING CONSIDERATIONS
Assess:

• 
Baselines of CBC, AST, ALT, bilirubin, platelets

• 
Infection:
sputum culture, lung sounds

• 
Signs of anemia: Hct, Hgb, fatigue

• 
Hepatic studies monthly: ALT, AST, bilirubin; decreased appetite, jaundice, dark urine, fatigue

• 
Renal status monthly: BUN, creatinine, output, specific gravity, urinalysis

 
Pseudomembranous colitis:
diarrhea, fever, abdominal pain/cramping, bloody diarrhea; discontinue if present, notify prescriber

Evaluate:

• 
Therapeutic response: decreased symptoms of TB, culture negative

Teach patient/family:

• 
That compliance with dosage schedule, duration necessary

• 
That scheduled appointments must be kept because relapse may occur

• 
That urine, feces, saliva, sputum, sweat, tears may be colored red-orange; that soft contact lenses, dentures may be permanently stained

 
To use alternative method of contraception; that oral contraceptive action may be decreased; to notify prescriber if pregnancy planned, suspected; to avoid breastfeeding

 
To report flulike symptoms: excessive fatigue, anorexia, vomiting, sore throat; unusual bleeding, yellowish discoloration of skin, eyes; diarrhea with pus, mucous, blood

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

rifaximin (Rx)

(rif-ax′i-min)

Xifaxan

Func. class.:
Antiinfective—miscellaneous

Chem. class.:
Analog of rifampin

Do not confuse:
rifaximin
/rifampin

ACTION:

Binds to bacterial-DNA–dependent RNA polymerase, thereby inhibiting bacterial RNA synthesis

USES:

Traveler’s diarrhea in those ≥12 yr caused by
E. coli
, hepatic encephalopathy

Unlabeled uses:
Crohn’s disease, diverticulitis

CONTRAINDICATIONS:

Hypersensitivity to product, rifamycins; diarrhea with fever, blood in stool

Precautions:
Pregnancy (C), breastfeeding, children, geriatric patients

DOSAGE AND ROUTES
Calculator
Traveler’s diarrhea

• Adult and child ≥12 yr:
PO
200 mg tid × 3 days without regard to meals

Hepatic encephalopathy

• Adult:
PO
550 mg bid

Crohn’s disease (unlabeled)

• Adult:
PO
200 mg tid × 16 wk

Diverticulitis (unlabeled)

• Adult:
PO
400 mg bid with mesalamine 800 mg tid × 7 days then 7 days/mo

Irritable bowel syndrome (unlabeled)

• Adult:
PO
550 mg tid × 14 day

Available forms:
Tabs 200, 550 mg

Administer:

• 
Without regard to food

SIDE EFFECTS

CNS:
Abnormal dreams, dizziness, insomnia

CV:
Hypotension, chest pain, peripheral edema

GI:
Abdominal pain, constipation, defecation urgency, flatulence, nausea, rectal tenesmus
, vomiting, ascites,
pseudomembranous colitis

MISC:
Headache, pyrexia
, motion sickness, tinnitus, rash, photosensitivity,
exfoliative dermatitis

MS:
Arthralgia

RESP:
Dyspnea, cough, pharyngitis

PHARMACOKINETICS

Half-life 1.8-4.5 hr, excreted in feces, peak 1-4 hr

NURSING CONSIDERATIONS
Assess:

• 
GI symptoms: amount, character of diarrhea; abdominal pain, nausea, vomiting, blood in stool, do not use in those with blood in stool, increased temperature with diarrhea

 
Overgrowth of infection, pseudomembranous colitis

Evaluate:

• 
Therapeutic response: absence of infection

Teach patient/family:

 
To discontinue rifaximin, notify prescriber if diarrhea persists >24-48 hr, if diarrhea worsens, or if blood in stools and fever present

• 
To avoid hazardous activities if dizziness occurs

• 
To notify prescriber if pregnancy planned, suspected

• 
That headache, rash, insomnia, abnormal dreams, tinnitus may occur

• 
To take without regard to food

• 
To take as directed, consume all of the product prescribed

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