activated charcoal

Brand Name

Acta-Char Liquid-A, Actidose-Aqua, Aqueous Charcodote [Canada], Charac-50 [Canada], CharcoAid 2000, Charcodote [Canada], Insta-Char, Insta-Char Aqueous Suspension, Liqui-Char, SuperChar Aqueous

Class and Category

Chemical class: Adsorbents

Therapeutic class: Antidotes

Pregnancy category: C

Indications and Dosages

Acute management of many oral poisonings following emesis/lavage.

Antidote

• PO (Adults): 25–100 g (may be repeated q 4–6 hr)..

• PO (Children 1–12 yr): 25–50 g (may be repeated q 4–6 hr)..

• PO (Children <1 yr): 1 g/kg (may be repeated q 4–6 hr)..

Availability

• Powder: 15-, 25- 30-[canada], 40-, 120-, 125-g 240-gOTC containers

• Oral suspension: 12.5 g/60 mLOTC, 15 g/72 mLOTC, 15 g/120 mLOTC, 25 g/120 mLOTC, 30 g/120 mLOTC, 50 g/240 mLOTC, 15 g/120 mLOTC, 25 g/125 mLOTC, 50 g/225 mLOTC, 50 g/250 mLOTC

• In combination with: sorbitol (Actidose with Sorbitol), Charcoaid, Pediatric Charcodote[canada], Charac-tol[canada], (Charcodote TFS)OTC[canada] 

Route     Onset                     Peak                       Duration

PO           within min                Unknown                 4–12 hr

Pharmacokinetics

Absorption: None.

Distribution: None.

Metabolism and Excretion: Excreted unchanged in the feces.

Half-life: Unknown.

Mechanism of Action

Binds drugs and chemicals in the GI tract.

Therapeutic Effect(s):

Decreased intestinal absorption of drugs or chemicals in the overdose situation.

Contraindication

No known contraindications.

Use Cautiously in:

• Poisonings due to cyanide, corrosives, ethanol, methanol, petroleum distillates, organic solvents, mineral acids, or iron;

• Endoscopic examination (observation will be obscured).

Drug Interactions

DRUG

Other drugs including ipecac syrup and laxatives will be adsorbed by charcoal and as a result will not be systemically absorbed from the GI tract.

FOOD

Milk, ice cream, or sherbet will decrease the ability of charcoal to absorb other agents.

Adverse Reactions

GI: black stools, constipation, diarrhea, vomiting.

Nursing Consideration

Assessment

• Assess neurologic status; administer only if patient is alert (unless airway is protected).

• Inquire as to the type of drug or poison and time of ingestion.

• Consult reference, poison control center, or physician for symptoms of toxicity of ingested agent(s).

• Monitor BP, pulse, respiratory and neurologic status, and urine output as indicated by toxicity of agent(s). Notify physician if symptoms persist or worsen.

Lab Test Considerations

• Chronic use may impair absorption of essential nutrients. This may result in decreased mineral or electrolyte levels.

 Potential Nursing Diagnoses

• Risk for self-directed violence (Indications)

• Risk for injury (Indications)

Implementation

• Treatment of Poisoning: Activated charcoal is most effective if administered within 30 min of ingestion of drug or poison. Dosage may be repeated for drugs subjected to enterohepatic elimination to minimize further absorption.

» If syrup of ipecac is used, administer ipecac first and wait until emesis occurs before administering activated charcoal.

• PO: Mix dose in 6–8 oz water; administer as a slurry (unless using suspension with or without sorbitol). Do not administer with milk products (milk, ice cream, or sherbet). May need to be diluted with additional water to be thin enough to administer through a nasogastric tube.

» Shake oral suspension well before administration.

» Rapid ingestion may cause vomiting. If vomiting occurs shortly after administering dose, confer with physician about repeating dose.

» Do not administer other oral drugs for 2 hr before or after administering activated charcoal.

» Slurry is constipating; physician may order a laxative to speed removal of the drug. May not be required with products containing sorbitol.

Patient/Family Teaching

• Inform patient that stools will turn black.

• Poisoning: When counseling, discuss methods of prevention, need to confer with poison control center, physician, or emergency department before administering, and need to bring ingested substance to emergency department for identification.

Evaluation/Desired Outcomes

Prevention or resolution of toxic effects of ingested agent.

diphenhydramine hydrochloride

Brand Name

Allerdryl (CAN), Banophen, Benadryl, Benadryl Allergy, Diphenhist CapTabs, Genahist, Hyrexin, Nytol QuickCaps, Siladryl, Sleep-Eze D Extra Strength, Unisom SleepGels Maximum Strength

Class and Category

Chemical class: Ethanolamine derivative

Therapeutic class: Antianaphylactic adjunct, antidyskinetic, antiemetic, antihistamine, antitussive (syrup), antivertigo, sedativehypnotic

Pregnancy category: B

Indications and Dosages

 To treat hypersensitivity reactions, such as perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, uncomplicated allergic skin eruptions, and transfusion reactions

CAPSULES, TABLETS

Adults and adolescents. 25 to 50 mg every 4 to 6 hr, p.r.n. Maximum: 300 mg daily.

Children ages 6 to 12. 12.5 to 25 mg every 4 to 6 hr. Maximum: 150 mg daily.

Children up to age 6. 6.25 to 12.5 mg every 4 to 6 hr.

ELIXIR

Adults and adolescents. 25 to 50 mg every 4 to 6 hr, p.r.n. Maximum: 300 mg daily.

Children. 1.25 mg/kg every 4 to 6 hr. Maximum: 300 mg daily.

I.V. OR I.M. INJECTION

Adults and adolescents. 10 to 50 mg every 4 to 6 hr up to 100 mg/dose, if needed. Maximum: 400 mg daily.

Children. 1.25 mg/kg every 4 to 6 hr. Maximum: 300 mg daily.

 To treat sleep disorders

CAPSULES, TABLETS

Adults and adolescents. 50 mg 20 to 30 min before bedtime.

 To provide antitussive effects

ELIXIR

Adults and adolescents. 25 mg every 4 hr. Maximum: 100 mg/24 hr.

Children ages 6 to 12. 12.5 mg every 4 to 6 hr. Maximum: 75 mg daily.

Children ages 2 to 6. 6.25 mg every 4 to 6 hr. Maximum: 25 mg daily.

 To prevent motion sickness or treat vertigo

CAPSULES, ELIXIR, TABLETS

Adults and adolescents. 25 to 50 mg every 4 to 6 hr, p.r.n. Maximum: 300 mg daily.

Children. 1 to 1.5 mg/kg every 4 to 6 hr, p.r.n. Maximum: 300 mg daily.

I.V. OR I.M. INJECTION

Adults and adolescents. Initial: 10 mg. Increased to 20 to 50 mg every 2 to 3 hr, if needed. Maximum: 100 mg/dose, 400 mg daily.

Children. 1 to 1.5 mg/kg I.M. every 4 to 6 hr, p.r.n. Maximum: 300 mg daily.

 To treat symptoms of Parkinson’s disease and drug-induced extrapyramidal reactions in elderly patients who can’t tolerate more potent antidyskinetic drugs

CAPSULES, ELIXIR, TABLETS

Adults. 25 mg t.i.d. increased gradually to 50 mg q.i.d., if needed. Maximum: 300 mg daily.

I.V. OR I.M. INJECTION

Adults and adolescents. 10 to 50 mg q.i.d., as needed. Maximum: 100 mg/dose, 400 mg daily.

Route     Onset                     Peak       Duration

P.O.         15–60 min                1–3 hr      6–8 hr

I.V.           Immediate                1–3 hr      6–8 hr

I.M.           30 min                      1–3 hr     6–8 hr

Mechanism of Action

Binds to central and peripheral H1 receptors, competing with histamine for these sites and preventing it from reaching its site of action. By blocking histamine, diphenhydramine produces antihistamine effects, inhibiting respiratory, vascular, and GI smooth-muscle contraction; decreasing capillary permeability, which reduces wheals, flares, and itching; and decreasing salivary and lacrimal gland secretions. Diphenhydramine produces antidyskinetic effects, possibly by inhibiting acetylcholine in the CNS. It also produces antitussive effects by directly suppressing the cough center in the medulla oblongata in the brain. Diphenhydramine’s antiemetic and antivertigo effects may be related to its ability to bind to CNS muscarinic receptors and depress vestibular stimulation and labyrinthine function. Its sedative effects are related to its CNS depressant action.

Contraindications

Bladder neck obstruction, hypersensitivity to diphenhydramine or its components, lower respiratory tract symptoms (including asthma), MAO inhibitor therapy, narrow- angle glaucoma, pyloroduodenal obstruction, stenosing peptic ulcer, symptomatic benign prostatic hyperplasia

Interactions

DRUGS

apomorphine: Possibly decreased emetic response in treatment of poisoning

barbiturates, other CNS depressants: Possibly\ increased CNS depression

MAO inhibitors: Increased anticholinergic and CNS depressant effects of diphenhydramine

ACTIVITIES

alcohol use: Possibly increased CNS depression

Adverse Reactions

CNS: Confusion, dizziness, drowsiness

CV: Arrhythmias, palpitations, tachycardia

EENT: Blurred vision, diplopia

GI: Epigastric distress, nausea

HEME: Agranulocytosis, hemolytic anemia, thrombocytopenia

RESP: Thickened bronchial secretions

SKIN: Photosensitivity

Nursing Considerations

• Expect to give parenteral form of diphenhydramine only when oral ingestion isn’t possible.

• Keep elixir container tightly closed. Protect elixir and parenteral forms from light.

• Expect to discontinue drug at least 72 hours before skin tests for allergies because drug may inhibit cutaneous histamine response, thus producing false-negative results.

PATIENT TEACHING

• Instruct patient to take diphenhydramine at least 30 minutes before exposure to situations that may cause motion sickness.

• Advise her to take drug with food to minimize GI distress.

• Urge patient to avoid alcohol while taking diphenhydramine.

• Instruct her to use sunscreen to prevent photosensitivity reactions.

• Advise patient to avoid taking other OTC drugs that contain diphenhydramine to prevent additive effects.

albuterol (salbutamol)

Brand Name

Proventil

albuterol sulfate (salbutamol sulphate)

AccuNeb, Airet, Gen-Salbutamol (CAN), Novo-Salmol (CAN), Proair HFA, Proventil, Proventil HFA, Proventil Repetabs, Proventil Syrup, Ventolin HFA, Ventolin Syrup, Volmax

Class and Category

Chemical class: Selective beta2-adrenergic agonist, sympathomimetic

Therapeutic class: Bronchodilator

Pregnancy category: C

Indications and Dosages

To prevent exercise-induced asthma

INHALATION AEROSOL

Adults and children over age 4. 2 inhalations 15 to 30 min before exercise.

To treat bronchospasm in patients with reversible obstructive airway disease or acute bronchospastic attack

E.R. TABLETS

Adults and children over age 12. Initial: 4 or 8 mg every 12 hr. Maximum: 32 mg daily in divided doses every 12 hr.

Children ages 6 to 12. Initial: 4 mg every 12 hr. Maximum: 24 mg daily in divided doses every 12 hr.

REPETABS

Adults and children over age 12. Initial: 4 to 8 mg every 12 hr. Maximum: 32 mg daily in divided doses every 12 hr.

Children ages 6 to 11. Initial: 4 mg every 12 hr. Maximum: 24 mg daily in divided doses every 12 hr.

SYRUP

Adults and children over age 14. Initial: 2 to 4 mg (1 to 2 tsp) t.i.d. or q.i.d. Maximum: 32 mg daily in divided doses.

Children ages 6 to 14. Initial: 2 mg (1 tsp) t.i.d. or q.i.d. Maximum: 24 mg daily in divided doses.

Children ages 2 to 6. Initial: 0.1 mg/kg t.i.d. (not to exceed 2 mg t.i.d.), increased to 0.2 mg/kg t.i.d. (not to exceed 4 mg t.i.d.).

TABLETS

Adults and children over age 12. Initial: 2 or 4 mg t.i.d. or q.i.d. Maximum: 32 mg daily in divided doses.

Children ages 6 to 12. Initial: 2 mg t.i.d. or q.i.d. Maximum: 24 mg daily in divided doses.

DOSAGE ADJUSTMENT

For elderly patients, initial dosage reduced to 2 mg (1 tsp) of syrup t.i.d. or q.i.d. or 2 mg of tablets t.i.d. or q.i.d. (up to 32 mg daily).

INHALATION AEROSOL

Adults and children age 4 and over. 1 inhalation every 4 hr to 2 inhalations every 4 to 6 hr.

INHALATION CAPSULES (ROTOCAPS) Adults and children age 4 and over. 200 mcg inhaled every 4 to 6 hr using inhalation device. Maximum: 400 mcg every 4 to 6 hr.

INHALATION SOLUTION

Adults and children age 12 and over. 2.5 mg t.i.d. or q.i.d. by nebulization over 5 to 15 min.

Children ages 2 to 12. Initial: 0.1 to 0.15 mg/kg t.i.d. or q.i.d. Maximum: 2.5 mg t.i.d. or q.i.d.

Mechanism of Action

Albuterol attaches to beta2 receptors on membrane bronchial cell membranes, which stimulates the intracellular enzyme adenylate cyclase to convert adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP). This reaction decreases intracellular calcium levels. It also increases intracellular levels of cAMP, as shown. Together, these effects relax bronchial smooth-muscle cells and inhibit histamine release.

Route                        Onset                     Peak                       Duration

P.O. (E.R. tab)            30 min                      2–3 hr                      12 hr

P.O. (syrup)               Rapid                       2 hr                          Unknown

P.O. (tab)                   30 min                      2–3 hr                      4–8 hr

Inhalation (aerosol)    5–15 min                  50–55 min                3–6 hr

Inhalation (rotocap)    5–15 min                  0.5–3 hr                   2–6 hr

Inhalation (sol’n)         5–15 min                  1–2 hr                      3–6 hr

Contraindications

Hypersensitivity to albuterol or its components

Interactions

DRUGS

beta blockers: Inhibited effects of albuterol

bronchodilators (sympathomimetics), such as

theophylline: Possibly adverse CV effects

digoxin: Decreased serum digoxin level

MAO inhibitors, tricyclic antidepressants: Increased vascular effects of albuterol

methyldopa: Increased vasopressor effect of methyldopa

potassium-lowering drugs: Possibly hypokalemia

potassium-wasting diuretics: Possibly increased hypokalemia

Adverse Reactions

CNS: Anxiety, dizziness, drowsiness, headache, hyperkinesia, insomnia, irritability, nervousness, tremor, vertigo, weakness

CV: Angina; arrhythmias, including atrial fibrillation, extrasystoles, supraventricular tachycardia, and tachycardia; chest pain; hypertension; hypotension; palpitations

EENT: Altered taste, dry mouth and throat, ear pain, glossitis, hoarseness, oropharyngeal edema, pharyngitis, rhinitis, taste perversion

ENDO: Hyperglycemia

GI: Anorexia, diarrhea, dysphagia, heartburn, nausea, vomiting

GU: UTI

MS: Muscle cramps

RESP: Bronchospasm, cough, dyspnea, paradoxical bronchospasm, pulmonary edema

SKIN: Diaphoresis, flushing, pallor, pruritus, rash, urticaria

Other: Angioedema, hypokalemia, infection, metabolic acidosis

Nursing Considerations

• Administer pressurized inhalations of albuterol during second half of inspiration, when airways are open wider and aerosol distribution is more effective.

WARNING Use cautiously in patients with cardiac disorders, diabetes mellitus, digitalis intoxication, hypertension, hyperthyroidism, or history of seizures. Albuterol can worsen these conditions.

•Monitor serum potassium level because albuterol may cause transient hypokalemia.

• Be aware that drug tolerance can develop with prolonged use.

PATIENT TEACHING

• Teach patient to use inhaler. Tell him to shake canister before use and to check that a new canister is working by spraying it the appropriate number of times (once to four times based on manufacturer instructions) into the air while looking for a fine mist.

• Instruct patient to wash mouthpiece with water once a week and let it air-dry.

• Advise patient to wait at least 1 minute between inhalations.

• Tell patient to check with his prescriber before using other inhaled drugs.

•Warn patient not to exceed prescribed dose or frequency. If doses become less effective, tell patient to contact his prescriber.

• Tell patient to immediately report signs and symptoms of allergic reaction, such as difficulty swallowing, itching, and rash.

glucagon

Brand Name

GlucaGen, Glucagon Diagnostic Kit, Glucagon Emergency Kit

Class and Category

Chemical class: Synthetic hormone

Therapeutic class: Antihypoglycemic, diagnostic aid adjunct

Pregnancy category: B

Indications and Dosages

To provide emergency treatment of severe hypoglycemia

I.V., I.M., OR SUBCUTANEOUS INJECTION

Adults and children weighing more than 20 kg (44 lb) or, with GlucaGen, more than 25 kg (55 lb). 1 mg, repeated in 15 min if needed.

Children weighing 20 kg or less or, with GlucaGen, 25 kg or less. 0.5 mg, or 0.02 to 0.03 mg/kg, repeated in 15 min, if needed.

To provide diagnostic assistance by inhibiting bowel peristalsis in radiologic examination of GI tract

I.V. INJECTION

Adults. 0.25 to 2 mg before procedure. Dose, route, and timing vary with segment of GI tract examined and length of procedure.

Route                     Onset                     Peak                       Duration

I.V.                           5–20                        Unknown                90 min

I.M.                           15–26                      Unknown                90 min

SubQ                       30–45                      Unknown                90 min

Mechanism of Action

Increases production of adenylate cyclase, which catalyzes conversion of adenosine triphosphate to cAMP, a process that in turn activates phosphorylase. Phosphorylase promotes breakdown of glycogen to glucose (glycogenolysis) in the liver. As a result, blood glucose level increases and GI smooth muscles relax.

Incompatibilities

Don’t mix glucagon with sodium chloride or solutions that have a pH of 3.0 to 9.5; use with dextrose solutions instead.

Contraindications

Hypersensitivity to glucagon or its components, pheochromocytoma

Interactions

DRUGS

oral anticoagulants: Possibly increased anticoagulant effects

Adverse Reactions

CV: Hypertension, hypotension (with hypersensitivity reaction), tachycardia

GI: Nausea, vomiting

RESP: Bronchospasm, respiratory distress

SKIN: Urticaria

Nursing Considerations

• Rouse patient as quickly as possible because prolonged hypoglycemia can cause cerebral damage.

• For I.V. use, reconstitute 1-mg vial of glucagon with 1 ml of diluent or 10-mg vial with 10 ml of diluent. Don’t give more than 1 mg/ml. For large doses, dilute with sterile water for injection.

• Before injecting glucagon, place unconscious patient on his side to prevent aspiration of vomitus when he regains consciousness.

• Administer by slow I.V. injection to decrease risk of adverse reactions, such as tachycardia and vomiting.

• If patient doesn’t respond to glucagon, expect to give I.V. dextrose.

•When patient is conscious or diagnostic procedure is completed, give oral carbohydrates to restore hepatic glycogen stores and prevent secondary hypoglycemia.

• Keep in mind that glucagon isn’t effective in patients with depleted hepatic glycogen stores caused by such conditions as adrenal insufficiency, chronic hypoglycemia, and starvation.

PATIENT TEACHING

• Instruct patient to monitor blood glucose level, especially with signs of hypoglycemia.

• Teach patient and family members how to recognize signs of hypoglycemia and when to notify prescriber.

• Advise patient to carry candy or other simple sugars to treat early hypoglycemia.

• Emphasize importance of a consistent diet, regular exercise, and proper use of insulin or oral antidiabetic drug.

•Make sure unstable diabetic patients and family members know how to give glucagon subcutaneously in case of hypoglycemia. Instruct family members to keep patient on his side and give him a carbohydrate when he awakens. Advise against giving fluids by mouth until patient is fully conscious.

• Instruct patient and family members to call for emergency medical assistance after glucagon treatment, especially if patient can’t ingest oral glucose or if he’s taking the sulfonylurea chlorpropamide, in case secondary hypoglycemia occurs.

dobutamine hydrochloride

Brand Name

Dobutrex

Class and Category

Chemical class: Synthetic catecholamine

Therapeutic class: Cardiac stimulant

Pregnancy category: Not rated

Indications and Dosages

To treat low cardiac output and heart failure

I.V. INFUSION

Adults. 2.5 to 10 mcg/kg/min as continuous infusion adjusted according to hemodynamic response.

Children. 5 to 20 mcg/kg/min as continuous infusion adjusted according to hemodynamic response.

Route                     Onset                     Peak                       Duration

I.V.                           1–2 min                    Unknown               Under 5 min

Mechanism of Action

Mainly stimulates beta1-adrenergic receptors, and mildly stimulates beta2- and alpha1-adrenergic receptors. Beta1-receptor stimulation produces a positive inotropic effect on the myocardium, increasing cardiac output by boosting myocardial contractility and stroke volume. Increased myocardial contractility raises coronary blood flow and myocardial oxygen consumption. Systolic blood pressure typically rises as a result of increased stroke volume. Other hemodynamic effects include decreased systemic vascular resistance, which reduces afterload, and decreased ventricular filling pressure, which reduces preload.

Incompatibilities

Don’t combine dobutamine with cefamandole, cefazolin, hydrocortisone sodium succinate, cephalothin, penicillin, sodium ethycrynate, and sodium heparin because of incompatibility. Don’t mix dobutamine with alkaline solutions, such as sodium bicarbonate, because of possible physical incompatibility. Don’t use diluents that contain sodium bisulfite or ethanol.

Contraindications

Hypersensitivity to dobutamine or its components, idiopathic hypertrophic subaortic stenosis

Interactions

DRUGS

beta blockers: Possibly increased alphaadrenergic activity and peripheral resistance

bretylium: Potentiated vasopressor activity, possibly arrhythmias cyclopropane, halothane: Possibly serious arrhythmias

guanethidine: Decreased hypotensive effect of guanethidine, possibly resulting in severe hypertension

thyroid hormones: Increased cardiovascular effects of thyroid hormones or dobutamine

tricyclic antidepressants: Possibly potentiated cardiovascular and vasopressor effects of dobutamine, resulting in arrhythmias, hyperpyrexia, or severe hypertension

Adverse Reactions

CNS: Fever, headache, nervousness, restlessness

CV: Angina, bradycardia, hypertension, hypotension, palpitations, PVCs, tachycardia

GI: Nausea, vomiting

RESP: Dyspnea

SKIN: Extravasation with tissue necrosis and sloughing, rash

Other: Hypokalemia

Nursing Considerations

• Avoid giving dobutamine to patients with uncorrected hypovolemia. Expect prescriber to order whole blood or plasma volume expanders to correct hypovolemia. Also avoid giving dobutamine to patients with acute MI because it can intensify or extend myocardial ischemia.

• Use drug cautiously in patients allergic to sulfites because drug may cause anaphylactic- like signs and symptoms; commercially available dobutamine injections contain sodium bisulfite. Also use drug cautiously in patients with atrial fibrillation because drug increases AV conduction. Keep in mind that patient should be adequately digitalized before administration.

• Dilute concentrate with at least 50 ml compatible I.V. solution. A common dilution is 500 mg (40 ml from 250-ml bag) in 210 ml D5W or normal saline solution to yield 2,000 mcg/ml. Or dilute 1,000 mg (80 ml from 250-ml bag) in 170 ml D5W or normal saline solution to yield 4,000 mcg/ml. Adjust maximum concentration according to patient’s fluid requirements as prescribed. Don’t exceed 5,000 mcg/ml. Discard solution after 24 hours.

• Inspect parenteral solution for particles and discoloration before administering it.

• Give I.V. drug using an infusion pump.

•Monitor blood pressure often during therapy, preferably by continuous intraarterial monitoring; systolic increase of 10 to 20 mm Hg may indicate dobutamineinduced increase in cardiac output.

• If hypotension develops, expect to reduce dosage or discontinue drug.

•Monitor heart rate and rhythm continuously for PVCs, which may result from drug’s stimulatory effect on heart’s conduction system, and sinus tachycardia, which results from positive chronotropic effect of beta stimulation and may increase heart rate by 5 to 15 beats/ minute.

•Monitor hemodynamic parameters, such as central venous pressure, pulmonary artery wedge pressure, and cardiac output, as indicated, to assess drug’s effectiveness.

WARNING Monitor serum potassium level to check for hypokalemia, a rare result of beta2 stimulation that causes electrolyte imbalance.

•Monitor urine output hourly, as appropriate, to check for improved renal blood flow.

• Dobutamine isn’t indicated for long-term treatment of heart failure because it may not be effective and may increase the risk of hospitalization and death.

PATIENT TEACHING

•Explain the need for frequent hemodynamic monitoring.

dopamine hydrochloride

Brand Name

Intropin, Revimine (CAN)

Class and Category

Chemical class: Catecholamine

Therapeutic class: Cardiac stimulant, vasopressor

Pregnancy category: C

Indications and Dosages

To correct hypotension that’s unresponsive to adequate fluid volume replacement or occurs as part of shock syndrome\ caused by bacteremia, chronic cardiac decompensation, drug overdose, MI, open-heart surgery, renal failure, trauma, or other major systemic illnesses; to improve low cardiac output

I.V. INFUSION

Adults. 0.5 to 3 mcg/kg/min for vasodilation of renal arteries; 2 to 10 mcg/kg/min for positive inotropic effects and increased cardiac output; 10 mcg/kg/min, increased gradually according to patient’s response, for increased systolic and diastolic blood pressures.

DOSAGE ADJUSTMENT

Initial dosage reduced to 10% of usual amount if patient has taken MAO inhibitor in previous 2 to 3 wk.

Children. 1 to 5 mcg/kg/min increased gradually in increments of 2.5 to 5 mcg/kg/min to achieve desired results. Maximum: 20 mcg/kg/min.

Route                     Onset                     Peak                       Duration

I.V.                           In 5 min                    Unknown                Up to 10min

Mechanism of Action

Stimulates dopamine1 (D1) and dopamine2 (D2) postsynaptic receptors. D1 receptors mediate vasodilation in renal, mesenteric, coronary, and cerebral blood vessels. D2 receptors inhibit norepinephrine release. In higher doses, dopamine also stimulates alpha1 and alpha2 receptors, causing vascular smooth-muscle contraction. At doses of 0.5 to 3 mcg/kg/min, this naturally occurring catecholamine mainly affects dopaminergic receptors in renal, mesenteric, coronary, and cerebral vessels, resulting in vasodilation, increased renal blood flow, improved GFR, and increased urine output. At doses of 2 to 10 mcg/kg/ min, dopamine stimulates beta1-adrenergic receptors, increasing cardiac output while maintaining dopaminergic-induced vasodilation. At doses of 10 mcg/kg/min or more, alpha-adrenergic agonism takes over, causing increased peripheral vascular resistance and renal vasoconstriction.

Incompatibilities

Don’t add dopamine to 5% sodium bicarbonate, alkaline I.V. solutions, oxidizing agents, or iron salts.

Contraindications

Pheochromocytoma, uncorrected ventricular fibrillation, ventricular tachycardia, and other tachyarrhythmias

Interactions

DRUGS

alpha blockers, haloperidol, loxapine, phenothiazines, thioxanthenes: Antagonized peripheral vasoconstriction with high doses of dopamine

anesthetics, such as chloroform, enflurane, halothane, isoflurane, and methoxyflurane: Increased risk of severe atrial and ventricular arrhythmias

antihypertensives, diuretics used as antihypertensives: Possibly decreased antihypertensive effects of these drugs

beta blockers: Antagonized beta receptor– mediated inotropic effects of dopamine

digitalis glycosides: Possibly increased risk of arrhythmias and additive inotropic effects

diuretics: Possibly increased diuretic effects of dopamine or diuretic

doxapram: Possibly increased vasopressor effects of dopamine or doxapram

ergot alkaloids: Enhanced peripheral vasoconstriction

guanadrel, guanethidine: Possibly decreased hypotensive effects of these drugs and potentiated vasopressor response to dopamine, resulting in hypertension and arrhythmias

levodopa: Increased risk of arrhythmias

MAO inhibitors: Prolonged and intensified cardiac stimulation and vasopressor effect

maprotiline, tricyclic antidepressants: Possibly potentiated cardiovascular and vasopressor effects of dopamine, resulting in arrhythmias, hyperpyrexia, or severe hypertension

mecamylamine, methyldopa: Possibly decreased hypotensive effects of these drugs and enhanced vasopressor effect of dopamine

methylphenidate: Possibly potentiated vasopressor effect of dopamine

nitrates: Possibly decreased antianginal effects of nitrates; possibly decreased vasopressor effect of dopamine, resulting in hypotension

oxytocic drugs: Possibly severe hypertension

phenoxybenzamine: Possibly antagonized peripheral vasoconstriction of dopamine, causing hypotension and tachycardia

phenytoin: Possibly sudden bradycardia and hypotension

rauwolfia alkaloids: Possibly decreased hypotensive effects of these drugs

sympathomimetics: Possibly increased adverse cardiovascular and other effects

thyroid hormones: Increased risk of coronary insufficiency

Adverse Reactions

CNS: Headache

CV: Angina, bradycardia, hypertension, hypotension, palpitations, peripheral vasoconstriction, sinus tachycardia, ventricular arrhythmias

GI: Nausea, vomiting

RESP: Dyspnea

SKIN: Extravasation with tissue necrosis

Nursing Considerations

• If possible, avoid giving dopamine to patients with occlusive vascular disease, such as atherosclerosis, Buerger’s disease, diabetic endarteritis, or Raynaud’s disease, because of risk of decreased peripheral circulation.

• Use drug cautiously in patients with cardiac disease, particularly coronary artery disease, because dopamine increases myocardial oxygen demand. Also use drug cautiously in patients allergic to sulfites, which are contained in some forms of dopamine.

• Inspect parenteral solution for particles and discoloration before administration.

• Dilute dopamine concentrate with a compatible I.V. solution before administering. Typical dilution is 400 mg in 250 ml to yield 1.6 mg/ml. Don’t exceed 3.2 mg/ml.

• If patient has hypovolemia, ensure adequate fluid resuscitation before giving drug.

• Give drug by I.V. infusion using an infusion pump.

WARNING When infusion rate exceeds 20 mcg/kg/min, monitor patient for excessive vasoconstriction and loss of renal vasodilating effects. Avoid using an infusion rate above 50 mcg/kg/min.

• If you must infuse more than 20 mcg/kg/ min of dopamine to maintain blood pressure, expect to infuse norepinephrine as prescribed.

• To avoid extravasation and tissue necrosis, administer infusion through a central catheter. If you must give drug via peripheral line, inspect site often for signs of extravasation and necrosis. If you detect such signs, start a new I.V. line for dopamine infusion, discontinue previous I.V. line, and notify prescriber immediately.

• If drug extravasates, expect to give 5 to 10 mg phentolamine diluted in 10 to 15 ml normal saline solution, as prescribed. Phentolamine infiltrates directly into area to antagonize vasoconstriction and minimize sloughing and tissue necrosis.

•Titrate dopamine gradually to minimize hypotension, especially after a high infusion rate.

•Monitor blood pressure continuously with an intra-arterial line, as indicated.

• Place patient on continuous ECG monitoring, and assess heart rate and rhythm for arrhythmias.

•Monitor patient’s hemodynamic parameters, such as central venous pressure, pulmonary artery wedge pressure, and cardiac output, as indicated, to assess effectiveness of dopamine therapy.

•Monitor urine output hourly as appropriate to assess patient for improved renal blood flow.

PATIENT TEACHING

• Explain the need for frequent hemodynamic monitoring.