Mosby's 2014 Nursing Drug Reference (262 page)

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

methylergonovine (Rx)

(meth-ill-er-goe-noe′veen)

Func. class.:
Oxytocic

Chem. class.:
Ergot alkaloid

ACTION:

Stimulates uterine, vascular, and smooth muscle, thereby causing contractions; decreases bleeding; arterial vasoconstriction

USES:

Treatment of hemorrhage postpartum or postabortion, uterine contractions

CONTRAINDICATIONS:

Pregnancy (other than obstetric delivery/abortion), hypertension, preeclampsia, eclampsia, elective induction of labor, hypersensitivity to ergot preparations

Precautions:
Severe renal/hepatic disease, jaundice, diabetes mellitus, seizure disorders, sepsis, CAD, last stage of labor

DOSAGE AND ROUTES
Calculator

• Adult:
PO
200 mcg tid-qid × ≤7 days;
IM/IV
200 mcg q2-4hr × 1-5 doses

Available forms:
Inj 200 mcg/ml; tabs 200 mcg

Administer:
PO route

• 
Do not exceed dosage limits

• 
Store tabs at room temperature

• 
Give with water

• 
Only during 4th stage of labor; not to be used to augment labor

IM route

• 
Protect from light

• 
IM in deep muscle mass; rotate inj sites for additional doses, aspirate

Direct IV route

• 
Undiluted through
Y
-tube or 3-way stopcock; give ≤0.2 mg/min or diluted in 5 ml 0.9% NaCl given through
Y
-site

• 
With crash cart available on unit; IV route used only in emergencies

• 
Refrigerated storage of ampules; protect from light; give only if solution is clear; colorless

Y-site compatibilities:
Heparin, hydrocortisone sodium succinate, potassium chloride, vit B/C

SIDE EFFECTS

CNS:
Headache, dizziness
,
seizures, hallucinations; stroke (IV)

CV:
Hypotension,
chest pain, palpitation,
hypertension, dysrhythmias, CVA (IV)

EENT:
Tinnitus

GI:
Nausea, vomiting

GU:
Cramping

INTEG:
Sweating, rash, allergic reactions

MS:
Leg cramps

RESP:
Dyspnea

PHARMACOKINETICS

Metabolized in liver, excreted in urine

PO:
Onset 5-25 min, duration 3 hr

IM:
Onset 2-5 min, duration 3 hr

IV:
Onset immediate, duration 45 min

INTERACTIONS

Increase:
vasoconstriction—DOPamine, ergots, anesthetics (regional), vasopressors, nicotine

Increase:
ergot toxicity—CYP3A4 inhibitors, do not use together

NURSING CONSIDERATIONS
Assess:

• 
B/P, pulse, character and amount of vaginal bleeding; watch for indications of hemorrhage

• 
Uterine relaxation; observe for severe cramping

 
Ergot toxicity:
tinnitus, hypertension, palpitations, chest pain, nausea, vomiting, weakness; cold, numb extremities

Evaluate:

• 
Therapeutic response: absence of hemorrhage

Teach patient/family:

• 
To report increased blood loss, severe abdominal cramps, fever or foul-smelling lochia

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

methylnaltrexone (Rx)

(meth-il-nal-trex′one)

Relistor

Func. class.:
Opioid antagonist

ACTION:

Peripheral μ-opioid receptor antagonist that reduces constipation associated with opiate agonists

USES:

Treatment of opioid-induced constipation in patients with advanced illness who are receiving palliative care when response to laxative therapy has been insufficient

Unlabeled uses:
Pruritus; nausea, vomiting related to morphine; urinary retention from opioids

CONTRAINDICATIONS:

Hypersensitivity, GI obstruction, IV route

Precautions:
Pregnancy (B), breastfeeding, children, geriatric patients, renal disease, diarrhea, driving, operating machinery, neoplastic disease, Crohn’s disease, peptic ulcer, ulcerative colitis

DOSAGE AND ROUTES
Calculator
Opiate-agonist–induced constipation

• Adult >114 kg:
SUBCUT
0.15 mg/kg every other day prn

• Adult 62-114 kg:
SUBCUT
12 mg every other day prn

• Adult 38-<62 kg:
SUBCUT
8 mg every other day prn

• Adult <38 kg:
SUBCUT
0.15 mg/kg every other day prn

Renal dose

• Adult:
SUBCUT
CCr <30 ml/min, reduce normal adult dose by 50%

Pruritus, nausea, and vomiting related to morphine (unlabeled) (oral dose investigational)

• Adult:
PO
19.2 mg/kg 20 min prior to morphine

Available forms:
Sol for inj 12 mg/0.6 ml

Administer:

• 
SUBCUT only; oral dose investigational, not currently available

• 
Do not give IV; IV dosing for urinary retention investigational

SUBCUT route

• 
Inspect sol before use; should be clear, colorless to pale yellow aqueous sol; do not use if particulate matter or discoloration are present

• 
Withdraw needed amount of sol into sterile syringe; if immediate administration is impossible, syringe may be kept at room temp for ≤24 hr; syringe does not need to be kept away from light during the 24-hr period; immediately discard any unused portion in vial; no preservatives are present

• 
Administer into upper arm, abdomen, or thigh ≤1×/24 hr; rotate inj sites; do not inject same spot each time; do not inject into areas where skin is tender,
bruised, red, or hard; avoid areas with scars or stretch marks

• 
If using with retractable needle, slowly push down on plunger past resistance point until the syringe is empty and click is heard

SIDE EFFECTS

CNS:
Dizziness

GI:
Nausea, vomiting, diarrhea, flatulence, abdominal pain

INTEG:
Hyperhidrosis

PHARMACOKINETICS

Terminal half-life 8 hr, protein binding 11%-15.3%; renal impairment has marked effect on renal excretion of methylnaltrexone; dose adjustment is required for patients with CCr <30 ml/min; renal clearance decreased and total systemic exposure increased in patients with severe renal impairment who receive single SUBCUT dose of 0.3 mg/kg

SUBCUT:
Peak 30 min

NURSING CONSIDERATIONS
Assess:

• 
Serum creatinine

• 
Opioid-induced constipation:
stool characteristics, bowel sounds during treatment

Perform/provide:

• 
Storage at 59° F-86° F (15° C-30° C); do not freeze

• 
Storage away from light

Evaluate:

• 
Therapeutic response: decreasing constipation

Teach patient/family:

• 
That, after 30 min, to remain near toilet facilities because bowel relaxation occurs, not to use more than 1 dose in 24 hr

• 
To notify prescriber of abdominal pain, continuous or severe diarrhea, nausea, vomiting

• 
Avoid use in pregnancy unless absolutely necessary; avoid in breastfeeding

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

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