Mosby's 2014 Nursing Drug Reference (251 page)

mafenide topical

 

MAGNESIUM SALTS
magnesium chloride (Rx)

Mag-64

magnesium citrate (
OTC
)
magnesium gluconate (
OTC
)

Mag-G, Magtrate

magnesium oxide (
OTC
)

Mag-Ox 400, Uro-Mag

magnesium hydroxide (
OTC
)

Freelax, MOM, Phillips’ Milk of Magnesia

magnesium sulfate (
OTC
, Rx)

epsom salts; magnesium sulfate (IV)—HIGH ALERT

Func. class.:
Electrolyte; anticonvulsant; saline laxative, antacid

ACTION:

Increases osmotic pressure, draws fluid into colon, neutralizes HCl

USES:

Constipation; bowel preparation before surgery or exam; anticonvulsant for preeclampsia, eclampsia (magnesium sulfate); electrolyte

Unlabeled uses:
Magnesium sulfate:
persistent pulmonary hypertension of the
newborn (PPHN), cardiac arrest, CPR, digitoxin/digoxin toxicity, premature labor, seizure prophylaxis, status asthmaticus, torsades de pointes, ventricular fibrillation/tachycardia

CONTRAINDICATIONS:

Hypersensitivity, abdominal pain, nausea/vomiting, obstruction, acute surgical abdomen, rectal bleeding, heart block, myocardial damage

Precautions:
Pregnancy (A); (B) (magnesium sulfate), renal/cardiac disease

DOSAGE AND ROUTES
Calculator
Laxative

• Adult:
PO
(Milk of Magnesia) 15-60 ml at bedtime

• Adult and child >12 yr:
PO
(magnesium sulfate) 15 g in 8 oz water;
PO
(Concentrated Milk of Magnesia) 5-30 ml;
PO
(magnesium citrate) 5-10 oz at bedtime

• Child 2-6 yr:
PO
(Milk of Magnesia) 5-15 ml/day

Prevention of magnesium deficiency

• Adult and child ≥10 yr:
PO
(male) 350-400 mg/day; (female) 280-300 mg/day; (breastfeeding) 335-350 mg/day; (pregnancy) 320 mg/day

• Child 8-10 yr:
PO
170 mg/day

• Child 4-7 yr:
PO
120 mg/day

Magnesium sulfate deficiency

• Adult:
PO
200-400 mg in divided doses tid-qid;
IM
1 g q6hr × 4 doses;
IV
5 g (severe)

• Child 6-12 yr:
PO
3-6 mg/kg/day in divided doses tid-qid

Pre-eclampsia/eclampsia (magnesium sulfate)

• Adult:
IM/IV
4-5 g IV inf; with 5 g
IM
in each gluteus, then 5 g q4hr or 4 g
IV INF,
then 1-2 g/hr
CONT INF,
max 40 g/day or 20 g/48 hr in severe renal disease

Persistent pulmonary hypertension of the newborn (PPHN) in mechanically ventilated neonates (unlabeled)

• Premature infants >33 wk and term neonates:
IV
(magnesium sulfate) 200 mg/kg over 20-30 min then
CONT IV INF
20-150 mg/kg/hr to maintain blood magnesium levels at 3.5-5.5 mmol/L

Status asthmaticus (unlabeled)

• Adult:
IV
(magnesium sulfate) 2 g

• Child:
IV INF
(PALS) (magnesium sulfate) 25-50 mg/kg diluted in D
5
W, given over 10-20 min, max 2 g/dose

Premature labor (unlabeled)

• Adult:
IV INF
(magnesium sulfate) 4-6 g given as a loading dose over 20-30 min then 2-4 g/hr
CONT INF;
use infusion pump until contractions cease; continue inf at lowest dose over 12-24 hr;
PO
(magnesium chloride/gluconate/oxide) 648-1200 mg/day elemental magnesium in divided doses

Torsades de pointes/cardiac dysrhythmias with hypomagnesemia (unlabeled)

• Adult:
IV
(magnesium sulfate) use ACLS guidelines or 1-2 g in 50-100 ml D
5
W given over 5-20 min in emergent cases or over 5-60 min

Available forms:
Chloride:
sus rel tabs 535 mg (64 mg Mg); enteric tabs 833 mg (100 mg Mg);
citrate:
oral sol 240-, 296-, 300-ml bottles (77 mEq/100 ml);
oxide:
tabs 400 mg; caps 140 mg;
hydroxide:
liq 400 mg/5 ml; conc liq 800 mg/5 ml; chew tabs 300, 600 mg;
sulfate:
powder for oral, bulk packages; epsom salts, bulk packages; inj 10%, 12.5%, 25%, 50%

Administer:
PO route

• 
With 8 oz water

• 
Refrigerate magnesium citrate before giving

• 
Shake susp before using as antacid at least 2 hr after meals

• 
Tablets should be chewed thoroughly before patient swallows; give 4 oz of water afterwards

• 
Laxative:
give on empty stomach

IM route (magnesium sulfate)

• 
Give deeply in gluteal site

IV route (magnesium sulfate)

• 
Only when calcium gluconate available for magnesium toxicity

Direct IV route

• 
Dilute 50% sol to ≤20%, give at ≤150 mg/min

Continuous IV INF route

• 
May dilute to 20% sol, infuse over 3 hr

• 
IV at less than 125 mg/kg/hr; circulatory collapse may occur; use inf pump

Y-site compatibilities:
Acyclovir, aldesleukin, amifostine, amikacin, ampicillin, aztreonam, ceFAZolin, cefoperazone, cefotaxime, cefOXitin, cephalothin, cepha-pirin, chloramphenicol, cisatracurium, DOBUTamine, doxycycline, DOXOrubicin liposome, enalaprilat, erythromycin, esmolol, famotidine, fludarabine, gallium, gentamicin, granisetron, heparin, HYDROmorphone, IDArubicin, insulin, kanamycin, labetalol, meperidine, metroNIDAZOLE, minocycline, morphine, moxalactam, nafcillin, ondansetron, oxacillin, PACLitaxel, penicillin G potassium, piperacillin, piperacillin/tazobactam, potassium chloride, propofol, remifentanil, sargramostim, thiotepa, ticarcillin, tobramycin, trimethoprim-sulfamethoxazole, vancomycin, vit B complex/C

SIDE EFFECTS

CNS:
Muscle weakness, flushing, sweating, confusion, sedation, depressed reflexes,
flaccid paralysis,
hypothermia

CV:
Hypotension, heart block,
circulatory collapse,
vasodilation

GI:
Nausea, vomiting, anorexia, cramps
, diarrhea

HEMA:
Prolonged bleeding time

META:
Electrolyte, fluid imbalances

RESP:
Respiratory depression/paralysis

PHARMACOKINETICS

PO:
Onset 1-2 hr

IM:
Onset 1 hr, duration 4 hr

IV:
Duration 1/2 hr

Excreted by kidney, effective anticonvulsant serum levels 2.5-7.5 mEq/L

INTERACTIONS

Increase:
effect of neuromuscular blockers

Increase:
hypotension—antihypertensives

Decrease:
absorption of tetracyclines, fluoroquinolones, nitrofurantoin

Decrease:
effect of digoxin

NURSING CONSIDERATIONS
Assess:

• 
Laxative:
cause of constipation; lack of fluids, bulk, exercise; cramping, rectal bleeding, nausea, vomiting; product should be discontinued

 
Eclampsia:
seizure precautions, B/P, ECG (magnesium sulfate);
magnesium toxicity:
thirst, confusion, decrease in reflexes; I&O ratio; check for decrease in urinary output

Evaluate:

• 
Therapeutic response: decreased constipation; absence of seizures (eclampsia), normal serum calcium levels

Teach patient/family:

• 
Not to use laxatives for long-term therapy because bowel tone will be lost

• 
That chilling improves taste of magnesium citrate

• 
To shake suspension well

• 
Not to give at bedtime as a laxative; may interfere with sleep; MOM is usually given at bedtime

• 
To give citrus fruit after administering to counteract unpleasant taste

• 
About reason for product, expected results

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

mannitol (Rx)

(man′i-tole)

Osmitrol, Resectisol

Func. class.:
Diuretic, osmotic

Chem. class.:
Hexahydric alcohol

ACTION:

Acts by increasing osmolarity of glomerular filtrate, which inhibits reabsorption of water and electrolytes and increases urinary output

USES:

Edema; promotion of systemic diuresis in cerebral edema; decrease in intraocular/intracranial pressure; im
proved renal function in acute renal failure, chemical poisoning

CONTRAINDICATIONS:

Active intracranial bleeding, hypersensitivity, anuria, severe pulmonary congestion, edema, severe dehydration, progressive heart, renal failure

Precautions:
Pregnancy (C), breastfeeding, geriatric patients, dehydration, severe renal disease, CHF, electrolyte imbalances

 

Black Box Warning:

Acute bronchospasm asthma

DOSAGE AND ROUTES
Calculator
Oliguria, prevention

• Adult:
IV
after initial test dose; if urine output is 30-50 ml/hr × 2 hr, give 20-100 g over a 24-hr period of 15% or 20% sol

Oliguria, treatment

• Adult:
IV
after initial test dose; give balance of 50 g of a 20% sol over 1 hr then 5% via
CONT IV INF
to maintain output at 50 ml/hr

• Child (unlabeled):
IV
0.5-2 g/kg as 15%-20% sol, run over 30-60 min; maintenance 0.25-0.5 g/kg q4-6hr

Intraocular pressure

• Adult:
IV
1.5-2 g/kg of 15%-25% sol over 30-60 min

ICP

• Adult:
IV
1-2 g/kg then 0.25-1 g/kg q4hr

Diuresis with drug intoxication

• Adult and child >12 yr:
5%-10% sol continuously up to 200 g
IV
while maintaining 100-500 ml urine output/hr

Available forms:
Inj 5%, 10%, 15%, 20%, 25%; GU irrigation: 5%

Administer:
Intermittent/Continuous IV route

• 
Change IV q24hr

• 
In 15%-25% sol with filter; rapid inf may worsen CHF; warm in hot water, shake to dissolve if crystals are present, use in-line filter, do not give as direct injection

• 
Test dose
with severe oliguria, 0.2 g/kg over 3-5 min; if continued oliguria, give 2nd test dose; if no response, reassess patient

Y-site compatibilities:
Acyclovir, aldesleukin, alemtuzumab, amifostine, amikacin, ampicillin, atropine, aztreonam, bivalirudin, bumetanide, calcium gluconate, caspofungin, ceFAZolin, cefotaxime, cefOXitin, cefTAZidime, ceftizoxime, chloramphenicol, cimetidine, cisatracurium, clindamycin, DAPTOmycin, dexmedetomidine, digoxin, diltiazem, diphenhydrAMINE, DOBUTamine, DOCEtaxel, DOPamine, DOXOrubicin liposome, doxycycline, enalaprilat, EPINEPHrine, ertapenem, esmolol, famotidine, fenoldopam, fentaNYL, fluconazole, fludarabine, gentamicin, granisetron, heparin, HYDROmorphone, hydrOXYzine, IDArubicin, imipenem/cilastatin, insulin, isoproterenol, ketorolac, labetalol, levofloxacin, lidocaine, linezolid, LORazepam, meperidine, metoclopramide, metoprolol, metroNIDAZOLE, micafungin, midazolam, milrinone, morphine, nafcillin, niCARdipine, nitroglycerin, nitroprusside, norepinephrine, ondansetron, oxaliplatin, PACLitaxel, palonosetron, pantoprazole, penicillin G potassium, phenylephrine, piperacillin/tazobactam, potassium chloride, procainamide, prochlorperazine, promethazine, propofol, propranolol, protamine, quinupristin/dalfopristin, ranitidine, remifentanil, sargramostim, sodium bicarbonate, tacrolimus, thiotepa, ticarcillin/clavulanate, tirofiban, tobramycin, trimethoprim/sulfamethoxazole, vancomycin, vasopressin, verapamil, vit B complex with C, voriconazole

SIDE EFFECTS

CNS:
Dizziness, headache,
seizures, rebound increased ICP,
confusion

CV:
Edema, thrombophlebitis, hypo/hypertension,
tachycardia,
angina-like chest pains, fever, chills,
CHF, circulatory overload

EENT:
Loss of hearing, blurred vision, nasal congestion, decreased intraocular pressure

ELECT:
Fluid, electrolyte imbalances,
acidosis
, electrolyte loss, dehydration, hypo/hyperkalemia

GI:
Nausea, vomiting
, dry mouth, diarrhea

GU:
Marked diuresis, urinary retention, thirst

RESP:
Pulmonary congestion

PHARMACOKINETICS

IV:
Onset 1-3 hr for diuresis, 1/2-1 hr for intraocular pressure, 15 min for cerebrospinal fluid; duration 4-6 hr for intraocular pressure, 3-8 hr for cerebrospinal fluid; excreted in urine; half-life 100 min

INTERACTIONS

Increase:
elimination of mannitol—lithium

Increase:
excretion of salicylates, barbiturates, imipramine, bromides

Increase:
hypokalemia—arsenic trioxide, cardiac glycosides, levomethadyl

Drug/Lab Test

Interference:
inorganic phosphorus, ethylene glycol

NURSING CONSIDERATIONS
Assess:

• 
Weight, I&O daily to determine fluid loss; effect of product may be decreased if used daily; output every hr prn

• 
B/P lying, standing; postural hypotension may occur

• 
Electrolytes: potassium, sodium, chloride; include BUN, CBC, serum creatinine, blood pH, ABGs, CVP, PAP

• 
Metabolic acidosis:
drowsiness, restlessness

• 
Hypokalemia:
postural hypotension, malaise, fatigue, tachycardia, leg cramps, weakness, or hyperkalemia

• 
Rashes, temp daily

• 
Confusion, especially in geriatric patients; take safety precautions if needed

• 
Hydration including skin turgor, thirst, dry mucous membranes, provide adequate fluids

• 
Blurred vision, pain in eyes before, during treatment
(increased intraocular pressure);
neurologic checks, intracranial pressure during treatment
(increased intracranial pressure)

Evaluate:

• 
Therapeutic response: improvement in edema of feet, legs, sacral area daily if medication being used with CHF; decreased intraocular pressure, prevention of hypokalemia, increased excretion of toxic substances; decreased ICP

Teach patient/family:

• 
To rise slowly from lying or sitting position

• 
About the reason for, method of treatment

• 
To report signs of electrolyte imbalance, confusion

TREATMENT OF OVERDOSE:

Discontinue inf; correct fluid, electrolyte imbalances; hemodialysis; monitor hydration, CV status, renal function

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