Aminophylline


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Chronic bronchospasm As aminophylline hydrate modified-release tab: Initial: 225-450 mg bid, increased as appropriate. IV Acute severe bronchospasm Loading: 5 mg/kg or 250-500 mg by slow inj or infusion. Maintenance: 0.5 mg/kg/hr. Max rate: 25 mg/min.
Dosage Details
Intravenous
Acute severe bronchospasm
Adult: Patient not receiving theophylline preparation: Loading: 5 mg/kg or 250-500 mg by slow inj or infusion over 20-30 min. Maintenance: 0.5 mg/kg/hr infusion. Max rate: 25 mg/min. Patient already receiving theophylline preparation: Loading dose is deferred until serum theophylline levels are determined, or if admin is required, 3.1 mg/kg.
Child: Loading: Same as adult dose. Maintenance: 6 mth to 9 yr 1 mg/kg/hr; 10-16 yr 0.8 mg/kg/hr.
Elderly: Maintenance: 0.3 mg/kg/hr.

Oral
Chronic bronchospasm
Adult: As aminophylline hydrate modified-release tab: Initially, 225-450 mg bid, increased as appropriate.
Child: As aminophylline hydrate modified-release tab: >40 kg: Initially, 225 mg bid, increased to 450 mg bid after 1 wk as appropriate.
Elderly: Dose reduction may be necessary.
Hepatic Impairment
Oral:
Chronic bronchospasm: Dose reduction may be necessary.

Intravenous:
Acute severe bronchospasm: Maintenance: 0.2 mg/kg/hr.
Administration
Should be taken on an empty stomach. Take at least 1 hr before or 2 hr after meals.
Incompatibility
Incompatible w/ metals and drugs that are unstable in alkaline soln or that would lower the pH below 8. Y-site admin: Amiodarone, ciprofloxacin, dobutamine, fenoldopam, hydralazine, isoproterenol, ondansetron, vinorelbine, warfarin. Syringe: Ceftriaxone, dimenhydrinate, doxapram, K phosphate.
Contraindications
Acute porphyria. Concomitant use w/ other xanthine derivatives.
Special Precautions
Patient w/ cardiac arrhythmia or failure, COPD, severe asthma, acute pulmonary oedema, peptic ulcer, hypo- and hyperthyroidism, glaucoma, DM, HTN, CHF, severe hypoxaemia, coronary artery disease, history of seizure, active influenza infection, acute febrile illness, sepsis. Patient undergoing influenza immunisation or in chronic alcoholism. Simultaneous admin by >1 route/preparation. Hepatic and renal impairment. Childn, elderly. Pregnancy and lactation.
Adverse Reactions
Nausea, vomiting, headache; hypokalaemia, hypophosphataemia, hypernatraemia, hyperglycaemia, acid/base disturbance; anxiety, insomnia, maniacal behaviour, delirium; confusion, restlessness, irritability, hyperventilation, vertigo/dizziness, tremor, convulsions; visual disturbances; palpitations, tachycardia, hypotension; abdominal pain, diarrhoea, gastro-oesophageal reflux, GI bleeding; maculo-papular rash, erythema, pruritus, urticaria, exfoliative dermatitis, rhabdomyolysis; hyperthermia, extreme thirst, transient diuresis.
Potentially Fatal: Cardiac arrhythmia, cardiorespiratory arrest, hypoxic encephalopathy.
MonitoringParameters
Monitor heart and resp rate, arterial/capillary blood gases, and serum K levels. Monitor serum theophylline levels prior to dose adjustment.
Overdosage
Symptoms: Tachycardia, fever, anorexia, nausea, vomiting, diarrhoea, haematemesis, restlessness, hypertonia, insomnia, irritability, headache, agitation, hallucinations, extreme thirst, dilated pupils, tinnitus, exaggerated limb reflexes, seizures, hypoxic encephalopathy, coma, palpitations, arrhythmias, hypotension, acute MI, cardiorespiratory arrest, hypokalaemia, hypomagnesaemia, hypophosphataemia, hyperglycaemia, albuminuria, hyperthermia, resp alkalosis, metabolic acidosis, rhabdomyolysis, increase creatine kinase, myoglobin, and leukocyte count. Management: Symptomatic and supportive treatment. Employ activated charcoal. Aggressive antiemetic therapy may be required. Treat seizures w/ IV diazepam 0.1-0.3 mg/kg (up to 10 mg). Restoration of fluid and electrolyte balance is necessary. Correct hypokalaemia w/ IV infusion of KCl. Administer IV propranolol to reverse extreme tachycardia, hypokalaemia, and hyperglycaemia except when patient has asthma. Charcoal haemoperfusion may be beneficial.
Drug Interactions
Increased clearance w/ aminoglutethimide, carbamazepine, moracizine, phenytoin, rifampicin, sulfinpyrazone, and barbiturates. Reduced clearance w/ allopurinol, carbimazole, cimetidine, ciprofloxacin, clarithromycin, diltiazem, disulfiram, erythromycin, fluconazole, interferon, isoniazid, isoprenaline, methotrexate, mexiletine, nizatidine, norfloxacin, oxpentifylline, propafenone, propranolol, ofloxacin, thiabendazole, verapamil, viloxazine HCl and OCs. May increase steady state concentration of phenytoin.
Potentially Fatal: Increased risk of toxicity w/ other xanthine derivatives.
Food Interaction
Increased clearance w/ St. John’s wort. Reduced half-life by 50% when taken w/ charcoal-broiled foods. Clearance may be increased w/ chronic consumption, or decreased w/ single large dose of alcohol.
Action
Description: Aminophylline, a xanthine derivative, is a complex of theophylline and ethylenediamine. It blocks phosphodiesterase-3 (PDE III), the enzyme that degrades 3’-5’-adenosine monophosphate (cAMP), promoting catecholamine stimulation of lipolysis, glycogenolysis, and gluconeogenesis and inducing release of epinephrine from adrenal medulla cells. This results in bronchodilation, diuresis, CNS and cardiac stimulation, and gastric acid secretion.
Pharmacokinetics:
Absorption: Rapidly and completely absorbed (oral) (as theophylline). Time to peak plasma concentration: 1-2 hr (oral); w/in 30 min (IV).
Distribution: Freely crosses the placenta and CSF; enters breast milk. Volume of distribution: 0.45 L/kg. Plasma protein binding: Approx 40%, mainly to albumin (as theophylline).
Metabolism: Readily liberates theophylline in the body which is subsequently metabolised (approx 90%) in the liver via N-demethylation by CYP1A2 enzyme and hydroxylation by CPY2E1 and CYP3A4 to the active metabolites, caffeine and 3-methylxanthine.
Excretion: Via urine (10% as unchanged). Elimination half-life: 8.7 hr (range: 6.1-12.8 hr).
Chemical Structure

Chemical Structure Image
Aminophylline

Source: National Center for Biotechnology Information. PubChem Database. Aminophylline, CID=9433, https://pubchem.ncbi.nlm.nih.gov/compound/Aminophylline (accessed on Jan. 20, 2020)

Storage
Store between 20-25°C. Protect from light and moisture.
ATC Classification
R03DA05 - aminophylline ; Belongs to the class of xanthines. Used in the systemic treatment of obstructive airway diseases.
References
Aminophylline Dihydrate Tablet (West-Ward Pharmaceutical Corp). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 15/09/2016.

Aminophylline Injection, Solution (American Regent Laboratories, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 15/09/2016.

Anon. Aminophylline. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 15/09/2016.

Buckingham R (ed). Aminophylline. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 15/09/2016.

Joint Formulary Committee. Aminophylline. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 15/09/2016.

Disclaimer: This information is independently developed by MIMS based on Aminophylline from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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