Aminophylline

MEDICATION SAFETY ISSUES
Sound-alike/look-alike issues:
Aminophylline may be confused with amitriptyline, ampicillin

PHARMACOLOGIC CATEGORY
Theophylline Derivative

DOSING: ADULTS
Treatment of acute bronchospasm: I.V.:
Loading dose (in patients not currently receiving aminophylline or theophylline): 6 mg/kg (based on aminophylline) administered I.V. over 20-30 minutes; administration rate should not exceed 25 mg/minute (aminophylline)
Approximate I.V. maintenance dosages: Based upon continuous infusions; bolus dosing may be determined by multiplying the hourly infusion rate by 24 hours and dividing by the desired number of doses/day
Smoker: 0.8 mg/kg/hour
Nonsmoker: 0.5 mg/kg/hour
Older patients and patients with cor pulmonale: 0.3 mg/kg/hour
Patients with congestive heart failure: 0.1-0.2 mg/kg/hour
Dosage should be adjusted according to serum level measurements during the first 12- to 24-hour period.

Reversal of adenosine-, dipyridamole-, or regadenoson-induced adverse reactions (eg, angina, hypotension) during nuclear cardiac stress testing (unlabeled use): I.V.: 50-250 mg administered over 30-60 seconds, repeat as necessary
Note: Since adenosine-induced side effects are short lived after discontinuation of the infusion, aminophylline administration is only very rarely required.

Bronchodilator: Oral: Initial: 380 mg/day (equivalent to theophylline 300 mg/day) in divided doses every 6-8 hours; may increase dose after 3 days; maximum dose: 928 mg/day (equivalent to theophylline 800 mg/day)

DOSING: PEDIATRIC

(For additional information see "Aminophylline: Pediatric drug information")
Treatment of acute bronchospasm: I.V.:
Loading dose: Patients not currently receiving aminophylline or theophylline: 6 mg/kg (based on aminophylline) administered I.V. over 20-30 minutes; administration rate should not exceed 25 mg/minute (aminophylline)
Approximate I.V. maintenance dosages: Based upon continuous infusions; bolus dosing (often used in children <6 months of age) may be determined by multiplying the hourly infusion rate by 24 hours and dividing by the desired number of doses/day
6 weeks to 6 months: 0.5 mg/kg/hour
6 months to 1 year: 0.6-0.7 mg/kg/hour
1-9 years: 1 mg/kg/hour
9-16 years: Refer to adult dosing.
Dosage should be adjusted according to serum level measurements during the first 12- to 24-hour period.

Bronchodilator: Oral: Children ≥ 45 kg: Refer to adult dosing.

DOSING: ELDERLY — Refer to adult dosing.

DOSAGE FORMS — Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Injection, solution, as dihydrate: 25 mg/mL (10 mL, 20 mL)

Injection, solution, as dihydrate [preservative free]: 25 mg/mL (10 mL, 20 mL)

Tablet, as dihydrate: 100 mg

DOSAGE FORMS: CONCISE
Injection, solution: 25 mg/mL (10 mL, 20 mL)

Injection, solution, [preservative free]: 25 mg/mL (10 mL, 20 mL)

Tablet: 100 mg

GENERIC EQUIVALENT AVAILABLE — Yes

ADMINISTRATION — Dilute with I.V. fluid to a concentration of 1 mg/mL and infuse over 20-30 minutes; maximum concentration: 25 mg/mL; maximum rate of infusion: 0.36 mg/kg/minute, and no greater than 25 mg/minute. I.M. administration is not recommended. Oral and I.V. should be administered around-the-clock rather than 4 times/day, 3 times/day, etc (eg, 12-6-12-6, not 9-1-5-9) to promote less variation in peak and trough serum levels.

For reversal of adenosine-, dipyridamole-, or regadenoson-induced adverse events during nuclear cardiac stress testing, administer I.V. undiluted over 30-60 seconds, repeat as necessary. Since adenosine-induced side effects are short lived after discontinuation of the infusion, aminophylline administration is only very rarely required.

COMPATIBILITY — Stable in dextran 6% in D5W, dextran 6% in NS, D5LR, D5NS, D51/2NS, D51/4NS, D5W, D10W, D20W, LR, 1/2NS, NS; variable stability (consult detailed reference) in fat emulsion 10%.

Y-site administration: Compatible: Allopurinol, amifostine, amphotericin B cholesteryl sulfate complex, aztreonam, ceftazidime, cimetidine, cladribine, docetaxel, doxorubicin liposome, enalaprilat, esmolol, etoposide, famotidine, filgrastim, fluconazole, fludarabine, foscarnet, gatifloxacin, gemcitabine, granisetron, heparin with hydrocortisone sodium succinate, inamrinone, labetalol, levofloxacin, linezolid, melphalan, meropenem, morphine, paclitaxel, pancuronium, piperacillin/tazobactam, potassium chloride, propofol, ranitidine, remifentanil, sargramostim, tacrolimus, teniposide, thiotepa, tolazoline, vecuronium, vitamin B complex with C. Incompatible: Amiodarone, ciprofloxacin, clarithromycin, dobutamine, hydralazine, ondansetron, vinorelbine, warfarin. Variable (consult detailed reference): Cisatracurium, diltiazem.

Compatibility in syringe: Compatible: Heparin, metoclopramide, pentobarbital, thiopental. Incompatible: Doxapram.

Compatibility when admixed: Compatible: Amobarbital, bretylium, calcium gluconate, chloramphenicol, cimetidine, dexamethasone, diphenhydramine, dopamine, erythromycin lactobionate, esmolol, floxacillin, flumazenil, furosemide, heparin, hydrocortisone sodium succinate, lidocaine, mephentermine, meropenem, methyldopate, metronidazole with sodium bicarbonate, nitroglycerin, pentobarbital, phenobarbital, potassium chloride, ranitidine, sodium bicarbonate, terbutaline. Incompatible: Atracurium, bleomycin, cefepime, ceftazidime, ceftriaxone, chlorpromazine, ciprofloxacin, clindamycin, dobutamine, doxorubicin, epinephrine, hydralazine, hydrocortisone sodium succinate with cephalothin sodium, hydroxyzine, insulin (regular), isoproterenol, levorphanol, meperidine, morphine, norepinephrine, papaverine with trimecaine, penicillin G potassium, pentazocine, prochlorperazine edisylate, prochlorperazine mesylate, promazine, promethazine, vitamin B complex with C. Variable (consult detailed reference): Amikacin, ascorbic acid, corticotropin, dimenhydrinate, methylprednisolone sodium succinate, nafcillin, procaine, vancomycin, verapamil, zinc.

USE — Bronchodilator in reversible airway obstruction due to asthma or COPD; increase diaphragmatic contractility

USE - UNLABELED / INVESTIGATIONAL — Reversal of adenosine-, dipyridamole-, or regadenoson-induced adverse reactions (eg, angina, hypotension) during nuclear cardiac stress testing

ADVERSE REACTIONS SIGNIFICANT
Uncommon at serum theophylline concentrations ≤ 15 mcg / mL

1% to 10%:
Cardiovascular: Tachycardia
Central nervous system: Nervousness, restlessness
Gastrointestinal: Nausea, vomiting

<1% (Limited to important or life-threatening): Allergic reactions, gastric irritation, insomnia, irritability, skin rash, seizure, tremor

CONTRAINDICATIONS — Hypersensitivity to theophylline, ethylenediamine, or any component of the formulation

WARNINGS / PRECAUTIONS
Concerns related to adverse effects: Theophylline toxicity: If a patient develops signs and symptoms of theophylline toxicity (eg, persistent, repetitive vomiting), a serum level should be measured and subsequent doses held.

Disease-related concerns: Cardiovascular disease: Use with caution in patients with hypertension or cardiac arrhythmias (excluding bradyarrhythmias). Hyperthyroidism: Use with caution in patients with hyperthyroidism. Peptic ulcer disease: Use with caution in patient with peptic ulcer disease. Seizure disorder: Use with caution in patients with a history of seizure disorder.

Other warnings/precautions: Dosage adjustments: Due to potential saturation of theophylline clearance at serum levels within (or in some patients less than) the therapeutic range, dosage adjustment should be made in small increments (maximum: 25% reduction). Monitoring: Due to wide interpatient variability, theophylline serum level measurements must be used to optimize therapy and prevent serious toxicity.

METABOLISM / TRANSPORT EFFECTS — Substrate of CYP1A2 (major), 2E1 (minor), 3A4 (minor)

DRUG INTERACTIONS
Adenosine: Theophylline Derivatives may diminish the therapeutic effect of Adenosine. Risk D: Consider therapy modification

Allopurinol: May increase the serum concentration of Theophylline Derivatives. Risk C: Monitor therapy

Aminoglutethimide: May increase the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Atomoxetine: May enhance the hypertensive effect of Sympathomimetics. Atomoxetine may enhance the tachycardic effect of Sympathomimetics. Risk C: Monitor therapy

Barbiturates: May increase the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Benzodiazepines: Theophylline Derivatives may diminish the therapeutic effect of Benzodiazepines. Risk D: Consider therapy modification

Beta-Blockers (Beta1 Selective): May diminish the bronchodilatory effect of Theophylline Derivatives. This is true at higher beta-blockers doses where cardioselectivity is lost. Risk C: Monitor therapy

Beta-Blockers (Nonselective): May diminish the bronchodilatory effect of Theophylline Derivatives. Risk D: Consider therapy modification

Cannabinoids: May enhance the tachycardic effect of Sympathomimetics. Risk C: Monitor therapy

CarBAMazepine: May increase the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Cimetidine: May decrease the metabolism of Theophylline Derivatives. Risk D: Consider therapy modification

CYP1A2 Inducers (Strong): May increase the metabolism of CYP1A2 Substrates. Risk C: Monitor therapy

CYP1A2 Inhibitors (Moderate): May decrease the metabolism of CYP1A2 Substrates. Risk C: Monitor therapy

CYP1A2 Inhibitors (Strong): May decrease the metabolism of CYP1A2 Substrates. Risk D: Consider therapy modification

Disulfiram: May increase the serum concentration of Theophylline Derivatives. Risk C: Monitor therapy

Febuxostat: May increase the serum concentration of Theophylline Derivatives. Risk X: Avoid combination

Fluvoxamine: May decrease the metabolism of Theophylline Derivatives. Risk D: Consider therapy modification

Interferons: May decrease the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Iobenguane I 123: Sympathomimetics may diminish the therapeutic effect of Iobenguane I 123. Risk X: Avoid combination

Isoniazid: May decrease the metabolism of Theophylline Derivatives. Risk D: Consider therapy modification

Lithium: Theophylline Derivatives may increase the excretion of Lithium. Risk C: Monitor therapy

Macrolide Antibiotics: May decrease the metabolism of Theophylline Derivatives. Exceptions: Azithromycin; Dirithromycin [Off Market]; Spiramycin; Telithromycin. Risk D: Consider therapy modification

Mexiletine: May decrease the metabolism of Theophylline Derivatives. Risk D: Consider therapy modification

Moricizine: May increase the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Pentoxifylline: May increase the serum concentration of Theophylline Derivatives. Risk C: Monitor therapy

Phenytoin: May increase the metabolism of Theophylline Derivatives. Theophylline Derivatives may decrease the serum concentration of Phenytoin. Risk C: Monitor therapy

Protease Inhibitors: May decrease the serum concentration of Theophylline Derivatives. Exceptions: Amprenavir; Fosamprenavir. Risk C: Monitor therapy

QuiNINE: May increase the serum concentration of Theophylline Derivatives. Risk C: Monitor therapy

Quinolone Antibiotics: May decrease the metabolism of Theophylline Derivatives. Ciprofloxacin and enoxacin are of greatest concern. Theophylline/quinolone therapy might augment the seizure-producing potential of each of the individual agents. Exceptions: Gatifloxacin; Gemifloxacin; Levofloxacin; Lomefloxacin; Moxifloxacin; Nalidixic Acid; Sparfloxacin; Trovafloxacin. Risk D: Consider therapy modification

Regadenoson: Aminophylline may diminish the vasodilatory effect of Regadenoson. Risk D: Consider therapy modification

Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Risk C: Monitor therapy

Tacrine: May decrease the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Thiabendazole: May decrease the metabolism of Theophylline Derivatives. Risk D: Consider therapy modification

Thyroid Products: May increase the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Ticlopidine: May decrease the metabolism of Theophylline Derivatives. Risk C: Monitor therapy

Zafirlukast: Theophylline Derivatives may decrease the serum concentration of Zafirlukast. Risk C: Monitor therapy

ETHANOL / NUTRITION / HERB INTERACTIONS — Food: Food does not appreciably affect absorption. Avoid extremes of dietary protein and carbohydrate intake. Changes in diet may affect the elimination of theophylline; charcoal-broiled foods may increase elimination, reducing half-life by 50%.

PREGNANCY RISK FACTOR — C (show table)

PREGNANCY IMPLICATIONS — Theophylline crosses the placenta; adverse effects may be seen in the newborn. Theophylline metabolism may change during pregnancy; monitor serum levels.

LACTATION — Enters breast milk/compatible (AAP rates "compatible")

BREAST-FEEDING CONSIDERATIONS — Irritability may be observed in the nursing infant.

PRICING — (data from drugstore.com)
Tablets (Aminophylline)
100 mg (30): $12.99
200 mg (90): $19.00

CANADIAN BRAND NAMES — Phyllocontin®; Phyllocontin®-350

INTERNATIONAL BRAND NAMES — Aminocont (FI); Aminofilina (EC, GT, PL); Aminomal (CH, CZ, IT); Aminophyllin (HR, NO); Aminophylline Renaudin (FR); Aminophyllinum (PL); Aminophyllinum Prolongatum (PL); Aminophyllinum Retard (HU, PL); Aminoslow (LU); Anephyllin (JP); Asiphylline (TW); Asthcontin (KP); Cardiomin (CN); Cardirenal (AR); Cardophyllin (AU); Carine (AU); Clonofillin SR (HU); Diaphyllin (HU); Escophyllin (CH); Eufilina (ES); Eufilina Mite (PT); Eufilina Venosa (ES); Euphyllin (AT, BE, BG, CH, CZ, DE, LU, NL); Euphyllin Retard (BF, BJ, CI, ET, GH, GM, GN, KE, LR, MA, ML, MR, MU, MW, NE, NG, SC, SD, SL, SN, TN, TZ, UG, ZA, ZM, ZW); Godafilin (ES); Kyophyllin (JP); Minophyl (IN); Neophyllin (SG); Pediatric Asthcontin for Children SR (KP); Peterphyllin (ZA); Pharmafil (MX); Phyllocontin (AE, BB, BF, BH, BJ, BM, BS, BZ, CI, CY, EG, ET, GB, GH, GM, GN, GY, IE, IL, IQ, IR, JM, JO, KE, KW, LB, LR, LY, MA, ML, MR, MU, MW, NE, NG, OM, PK, QA, SA, SC, SD, SL, SN, SR, SY, TN, TT, TW, TZ, UG, YE, ZA, ZM, ZW); Phyllocontin Continus (AE, BH, CY, EG, IL, IQ, IR, JO, KW, LB, LY, OM, QA, SA, SY, YE); Phyllotemp (CH, DE, GR); Planphylline (FR); Retafilin (HR); Tefamin (IT); Teofylamin (DK); Teofyllamin Ipex (SE); Unifilin (BR)

MECHANISM OF ACTION — Causes bronchodilatation, diuresis, CNS and cardiac stimulation, and gastric acid secretion by blocking phosphodiesterase which increases tissue concentrations of cyclic adenine monophosphate (cAMP) which in turn promote catecholamine stimulation of lipolysis, glycogenolysis, and gluconeogenesis and induce release of epinephrine from adrenal medulla cells

PHARMACODYNAMICS / KINETICS
Theophylline:

Absorption: Oral: Dosage form dependent

Distribution: 0.45 L/kg based on ideal body weight

Protein binding: 40%, primarily to albumin

Metabolism: Children >1 year and Adults: Hepatic; involves CYP1A2, 2E1, and 3A4; forms active metabolites (caffeine and 3-methylxanthine)

Half-life elimination: Highly variable and dependent upon age, liver function, cardiac function, lung disease, and smoking history

Time to peak, serum:
Oral: Immediate release: 1-2 hours
I.V.: Within 30 minutes

Excretion: Children >3 months and Adults: Urine (10% as unchanged drug)

PATIENT INFORMATION — Do not drink or eat large quantities of caffeine-containing beverages or food (colas, coffee, chocolate).