Phyllocontin


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aminophylline (theophylline, ethylenediamine)

Amnivent (UK), Phyllocontin (UK)

Pharmacologic class: Xanthine

Therapeutic class: Bronchodilator

Pregnancy risk category C

Action

Unclear. Thought to directly relax smooth muscle of bronchial airways and increase pulmonary blood flow by inhibiting phosphodiesterase.

Availability

Injection: 250 mg/10 ml

Oral liquid: 105 mg/5 ml

Tablets: 100 mg, 200 mg

Indications and dosages

Symptomatic relief of bronchospasm in patients with acute symptoms who require rapid theophyllinization

Adults (nonsmokers): 0.7 mg/kg/hour I.V. for first 12 hours. Maintenance dosage is 0.5 mg/kg/hour I.V.

Children ages 9 to 16: 1 mg/kg/hour I.V. for first 12 hours. Maintenance dosage is 0.8 mg/kg/hour I.V.

Children ages 6 months to 9 years: 1.2 mg/kg/hour I.V. for first 12 hours. Maintenance dosage is 1 mg/kg/hour I.V.

Chronic bronchial asthma

Adults and children: Dosage is highly individualized. Common initial dosage is 16 mg/kg/24 hours I.V. or 400 mg/24 hours I.V. in divided doses at 6- or 8hour intervals. If needed, dosage may be increased 25% at 3-day intervals.

Dosage adjustment

• Heart failure
• Hepatic disease
• Elderly patients
• Smokers

Off-label uses

• Dyspnea in patients with chronic obstructive pulmonary disease (COPD)

Contraindications

• Hypersensitivity to xanthine compounds or ethylenediamine
• Seizure disorders

Precautions

Use cautiously in:
• COPD, diabetes mellitus, glaucoma, renal or hepatic disease, heart failure or other cardiac or circulatory impairment, hypertension, hyperthyroidism, peptic ulcer, severe hypoxemia
• active peptic ulcer disease
• elderly patients
• neonates, infants, and young children.

Administration

• For I.V. use, dilute according to label directions and infuse at a rate no faster than 25 mg/minute.
• Don't give in I.V. solutions containing invert sugar, fructose, or fat emulsions.
• Give oral form at meals with 8 oz of water.

Adverse reactions

CNS: irritability, dizziness, nervousness, restlessness, headache, insomnia, stammering speech, abnormal behavior, mutism, unresponsiveness alternating with hyperactivity, seizures

CV: palpitations, sinus tachycardia, extrasystoles, marked hypotension, arrhythmias, circulatory failure

GI: nausea, vomiting, diarrhea, epigastric pain, hematemesis, gastroesophageal reflux, anorexia

GU: urine retention (in men with enlarged prostate), diuresis, increased excretion of renal tubular cells and red blood cells, proteinuria

Metabolic: hyperglycemia

Musculoskeletal: muscle twitching

Respiratory: tachypnea, respiratory arrest

Skin: flushing

Other: fever, hypersensitivity reactions (including exfoliative dermatitis and urticaria)

Interactions

Drug-drug.Adenosine: decreased antiarrhythmic effect of adenosine

Barbiturates, nicotine, phenytoin, rifampin: decreased aminophylline blood level

Beta-adrenergic blockers: antagonism of aminophylline effects

Calcium channel blockers, cimetidine, ciprofloxacin, disulfiram, erythromycin, hormonal contraceptives, influenza vaccine, interferon, methotrexate: elevated aminophylline blood level

Carbamazepine, isoniazid, loop diuretics (such as furosemide): increased or decreased aminophylline blood level

Ephedrine, other sympathomimetics: toxicity, arrhythmias

Lithium: increased lithium excretion

Drug-diagnostic tests.Aspartate aminotransferase, glucose: increased levels

Drug-herbs.Cayenne: increased risk of aminophylline toxicity

Drug-behaviors.Smoking: increased aminophylline elimination

Patient monitoring

Monitor aminophylline blood level. Adjust dosage if patient has signs or symptoms of toxicity (tachycardia, headache, anorexia, nausea, vomiting, diarrhea, restlessness, and irritability).
• Assess for arrhythmias, especially after giving loading dose.
• Check vital signs and fluid intake and output.
• Monitor patient's response to drug, and assess pulmonary function test results.

Patient teaching

• Advise patient to take oral doses at meals with 8 oz of water.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Tell patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.
• Advise patient to establish effective bedtime routine to minimize insomnia.
• Caution patient not to change aminophylline brands.
• If patient smokes, tell him to notify prescriber if he stops smoking; dosage may need to be adjusted.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.

aminophylline

(am-in-off-i-lin) ,

Phyllocontin

(trade name)

Classification

Therapeutic: bronchodilators
Pharmacologic: xanthines
Pregnancy Category: C

Indications

Long-term control of reversible airway obstruction caused by asthma or COPD.Increases diaphragmatic contractility.Respiratory and myocardial stimulant in premature infant apnea (apnea of prematurity).

Action

Inhibits phosphodiesterase, producing increased tissue concentrations of cyclic adenosine monophosphate (cAMP). Increased levels of cAMP result in:
  • Bronchodilation,
  • CNS stimulation,
  • Positive inotropic and chronotropic effects,
  • Diuresis,
  • Gastric acid secretion. Aminophylline is a salt of theophylline and releases free theophylline after administration.

Therapeutic effects

Bronchodilation.

Pharmacokinetics

Absorption: Aminophylline releases theophylline after administration.
Distribution: Widely distributed as theophylline; crosses the placenta; breast milk concentrations are 70% of plasma levels; not distributed into adipose tissue.
Metabolism and Excretion: Aminophylline is converted to theophylline; theophylline is metabolized by the liver (90%) to caffeine, which may accumulate in neonates; metabolites are renally excreted; 10% excreted unchanged by the kidneys.
Half-life: Theophylline—Premature infants: 20–30 hr; Term infants: 11–25 hr; Children 1–4 yr: 3.4 hr; Children 6–17 yr: 3.7 hr; Adults: 9–10 hr (↑ in patients >60 yr, patients with HF or liver disease; ↓ in cigarette smokers ).

Time/action profile (bronchodilation)

ROUTEONSET†PEAKDURATION
IVrapidend of infusion6–8 hr
†Provided that a loading dose has been given and steady-state blood levels exist

Contraindications/Precautions

Contraindicated in: Hypersensitivity to aminophylline or theophylline.
Use Cautiously in: Cardiac arrhythmias; Heart failure, liver disease, or hypothyroidism (dose ↓ required); Peptic ulcer disease; Seizure disorder; Obstetric / / Lactation: Safety not established; Pediatric: Dose ↓ required in children < 1 yr; Geriatric: Initial dose ↓ may be necessary in geriatric or debilitated patients.

Adverse Reactions/Side Effects

Central nervous system

  • seizures (life-threatening)
  • anxiety (most frequent)
  • headache
  • insomnia
  • irritability

Cardiovascular

  • arrhythmias (life-threatening)
  • tachycardia (most frequent)
  • angina
  • palpitations

Dermatologic

  • rash

Gastrointestinal

  • nausea (most frequent)
  • vomiting (most frequent)
  • anorexia

Neurologic

  • tremor

Interactions

Drug-Drug interaction

Additive CV and CNS side effects with adrenergics (sympathomimetic).May ↓ the therapeutic effect of lithium and phenytoin.Smoking, barbiturates, carbamazepine, phenytoin, nevirapine and rifampin may ↑ metabolism and may ↓ effectiveness.Erythromycin, beta blockers, clarithromycin, calcium channel blockerscimetidine,hormonal contraceptives, disulfiram, doxycycline, estrogens, fluvoxamine, isoniazid, ketoconazole, mexiletine, nefazodone, protease inhibitors, quinidine, some fluoroquinolones, and large doses of allopurinol ↓ metabolism and may lead to toxicity.Caffeine-containing herbs (cola nut, guarana, mate, tea, coffee) may ↑ serum levels and risk of CNS and CV side effects.↓ serum levels and effectiveness with St. John’s wort.Excessive regular intake of charcoal-broiled foods may ↓ effectiveness.

Route/Dosage

Dose should be determined by theophylline serum level monitoring. Loading dose should be decreased or eliminated if theophylline preparation has been used in preceding 24 hr. Aminophylline is 80% theophylline (100 mg aminophylline = 80 mg theophylline).
Intravenous (Adults) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 0.7 mg/kg/hr (0.56 mg/kg/hr of theophylline) via continuous infusion (non-smoking adults); an infusion rate of 0.9 mg/kg/hr (0.72 mg/kg/hr of theophylline) should be used for adults who smoke.
Intravenous (Geriatric Patients and Adult Patients with Cor Pulmonale) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 0.6 mg/kg/hr (0.47 mg/kg/hr of theophylline) via continuous infusion.
Intravenous (Adults with HF or Liver Failure) Loading dose—6 mg/kg (4.7 mg/kg/hr of theophylline) given over 20–30 min, followed by 0.5 mg/kg/hr (0.39 mg/kg/hr of theophyliine) via continuous infusion.
Intravenous (Children 12–16 yr) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 0.7 mg/kg/hr (0.56 mg/kg/hr of theophylline) via continuous infusion.
Intravenous (Children 9–12 yr) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 0.9 mg/kg/hr (0.72 mg/kg/hr of theophylline) via continuous infusion.
Intravenous (Children 1–9 yr) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 1–1.2 mg/kg/hr (0.8–0.96 mg/kg/hr of theophylline) via continuous infusion.
Intravenous (Children 6 mo–1 yr) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 0.6–0.7 mg/kg/hr (0.48–0.56 mg/kg/hr of theophylline) via continuous infusion.
Intravenous (Children 6 wk–6 mo) Loading dose—6 mg/kg (4.7 mg/kg of theophylline) given over 20–30 min, followed by 0.5 mg/kg/hr (0.4 mg/kg/hr of theophylline) via continuous infusion.

Availability (generic available)

Injection: 25 mg/mL

Nursing implications

Nursing assessment

  • Assess BP, pulse, respiratory status (rate, lung sounds, use of accessory muscles, number and severity of apnea spells in infants) before and throughout therapy. Ensure that oxygen therapy is correctly instituted during acute asthma attacks.
    • Monitor intake and output ratios for an increase in diuresis or fluid overload.
    • Monitor patients with a history of cardiovascular problems for chest pain and ECG changes (PACs, supraventricular tachycardia, PVCs, ventricular tachycardia). Resuscitative equipment should be readily available.
    • Monitor pulmonary function tests before and periodically during therapy to determine therapeutic efficacy in patients with chronic bronchitis or emphysema.
  • Lab Test Considerations: Monitor ABGs, acid-base, and fluid and electrolyte balance in patients receiving parenteral therapy or whenever required by patient’s condition.
  • Monitor drug levels routinely, especially in patients requiring high doses or during prolonged intensive therapy. Serum sample should be obtained at time of peak absorption. Peak levels should be evaluated 30 min after a 30 min IV loading dose, 12–24 hr after initiation of a continuous infusion and 1–2 hr after rapid-acting oral forms, and 4–12 hr after extended-release oral forms. Therapeutic plasma levels range from 10–15 mcg/mL for asthma and 6–14 mcg/mL for apnea of prematurity. Drug levels in excess of 20 mcg/mL are associated with toxicity. Caffeine ingestion may falsely elevate drug concentration levels.
    • Observe for symptoms of drug toxicity (anorexia, nausea, vomiting, stomach cramps, diarrhea, confusion, headache, restlessness, flushing, increased urination, insomnia, tachycardia, arrhythmias, seizures). Notify health care professional immediately if these occur. Tachycardia, ventricular arrhythmias, or seizures may be the first sign of toxicity.
    • Geriatric: Patients over 60 yr have ↑ risk of toxicity and sensitivity to toxic effects due to age-related pharmacodynamic and pharmacokinetic changes. Assess frequently.

Potential Nursing Diagnoses

Ineffective airway clearance (Indications)
Activity intolerance (Indications)

Implementation

  • Administer around the clock to maintain therapeutic plasma levels.
  • Intravenous Administration
  • pH: 8.6–9.0.
  • Intravenous: Diluent: May be diluted in D5W, D10W, D20W, 0.9% NaCl, 0.45% NaCl, D5/0.9% NaCl, D5/0.45% NaCl, D5/0.25% NaCl, or LR. Concentration: 1 mg/mL. Maximum concentrationis 25 mg/mL. Mixture is stable for 24 hr if refrigerated.
    • Do not administer discolored or precipitated solution. Flush main IV line before administration.
    • If extravasation occurs, local injection of 1% procaine and application of heat may relieve pain and promote vasodilation.
  • Loading Dose: Administer over 20–30 min.
  • Rate: Do not exceed 20–25 mg/min in adults or 0.36 mg/kg/min in children. Administer via infusion pump to ensure accurate dosage. Rapid administration may cause chest pain, dizziness, hypotension, tachypnea, flushing, arrhythmias, or a reaction to the solution or administration technique (chills; fever; redness, pain, or swelling at injection site).
  • Continuous Infusion: Usually given as a loading dose in a small volume followed by continuous infusion in larger volume.
  • Rate: See Route and Dosage section for rates.
  • Y-Site Compatibility: acyclovir, alemtuzumab, alfentanil, allopurinol, amifostine, amikacin, amphotericin B cholesteryl, amphotericin B lipid complex, amphotericin B liposome, anidulafungin, argatroban, atropine, azithromycin, aztreonam, benztropine, bivalirudin, bleomycin, bumetanide, butorphanol, calcium chloride, calcium gluconate, carboplatin, carmustine, caspofungin, cefazolin, cefoperazone, cefotaxime, cefotetan, cefoxitin, ceftazidime, ceftriaxsone, cefuroxime, chloramphenicol, cisplatin, cladribine, clindamycin, clonidine, cyanocobalamin, cyclosphophamide, cyclosporine, cytarabine, dactinomycin, daptomycin, dexamethasone, dexmedetimodine, digoxin, docetaxel, dopamine, doripenem, doxacurium, doxorubicin liposome, doxycycline, enalaprilat, epinephrine, epoetin alfa, eptifibatide, ertapenem, erythromycin, esmolol, etoposide, etoposide phosphate, famotidine, fentanyl, filgrastim, fluconazole, fludarabine, fluorouracil, folic acid, foscarnet, furosemide, gemcitabine, gentamicin, glycopyrrolate, granisetron, heparin, hetastarch, hydrocotisone, hydromorphone, ifosfamide, indomethacin, insulin, irinotecan, ketorolac, labetalol, leucovorin, levofloxacin, lidocaine, linezolid, lorazepam, mannitol, mechlorethamine, melphalan, meperidine, meropenem, metaraminol, methotrexate, methyldopate, methylprednisolone, metoclopramide, metoprolol, metronidazole, micafungin, milrinone, mitoxantrone, morphine, multivitamins, nafcillin, nalbuphine, naltrexone, nesiritide, nitroglycerin, nitroprusside, octreotide, oxacillin, oxytocin, paclitaxel, palonosetron, pamidronate, pancuronium, pantoprazole, permetrexed, pentobarbital, phenobarbital, phentolamine, phenylephrine, phytonadione, piperacillin/tazobactam, potassium acetate, potassium chloride, procainamide, propofol, propranolol, protamine, pyridoxime, ranitidine, remifentanil, rituximab, rocuronium, sargramostim, sodium acetate, sodium bicarbonate, streptokinase, succinylcholine, sufentanil, tacrolimus, teniposide, theophylline, thiotepa, ticarcillin/clavulanate, tigecycline, tirofiban, tobramycin, tolazoline, trastuzumab, trimetaphan, vasopressin, vecuronium, vincristine, vitamin B complex with vitamin C, voriconazole, zolendronic acid
  • Y-Site Incompatibility: amiodarone, ampicillin, ascorbic acid, atracurium, buprenorphine, chlorpromazine, ciprofloxacin, dantrolene, dexrazoxane, diazepam, diazoxide, diphenhydramine, dobutamine, doxorubicin, epinephrine, epirubicin, ganciclovir, haloperidol, hydralazine, hydroxyzine, idarubicin, isoproterenol, magnesium sulfate, midazolam, minocycline, mycophenolate, norepinephrine, ondansetron, papaverine, penicillin G, pentamidine, pentazocine, phenytoin, prochlorperazine, promethazine, quinupristin/dalfopristin, thiamine, trimethoprim/sulfamethoxazole, vancomycin, verapamil, vinorelbine, warfarin
  • Additive Incompatibility: Admixing is not recommended because of dose titration and incompatibilities.

Patient/Family Teaching

  • Encourage the patient to drink adequate liquids (2000 mL/day minimum) to decrease the viscosity of the airway secretions.
  • Advise patient to avoid OTC cough, cold, or breathing preparations without consulting health care professional. These medications may increase side effects and cause arrhythmias.
  • Encourage patients not to smoke. A change in smoking habits may necessitate a change in dose.
  • Advise patient to minimize intake of xanthine-containing foods or beverages (colas, coffee, chocolate) and not to eat charcoal-broiled foods daily.

Evaluation/Desired Outcomes

  • Increased ease in breathing.
    • Clearing of lung fields on auscultation.
  • Respiratory and myocardial stimulation in apnea of infancy.

Phyllocontin

A brand name for AMINOPHYLLINE.