Theophylline toxicity
Theophylline toxicity and other methylxanthines
OVERVIEW
- theophylline and caffeine are the most commonly encountered methylxanthines
- theophylline = water soluble aminophylline derivative
- cAMP phosphodiesterase inhibitors
- used to treat asthma
- minimal efficacy with a number of adverse side effects -> some emerging data that useful in the critically ill patient
- caffeine -> used in prevention of neonatal apnoea
CLINICAL FEATURES
Theophylline
- <10mg/mL: nausea, vomiting, diarrhoea – >10mg/L: tachycardia, tremors, metabolic abnormalities
- >25mg/L: tachycardia, arrhythmias
- > 50mg/L: cardiovascular collapse
- >80mg/L: seizures
MANAGEMENT
Resuscitation
- supraventricular arrhythmias: beta blockers or calcium channel blockers, fluids
- seizures: benzodiazepines, phenobarbital (avoid phenytoin -> can worsen seizures)
Acid-base and Electrolytes
- hypokalaemia, hypomagnesaemia, hypercalcaemia, hyperglycaemia -> routine care
Specific Therapy
- multiple dose charcoal: theophylline undergoes significant enterohepatic re-circulation
- CVVDHF: acceptable alternative to haemoperfusion
- monitor levels Q2hrly
Underlying Cause
- multiple factors affect clearance of theophylline: hepatic disease, CHF, fever, age, infection, thyroid state
References and Links
CCC Toxicology Series
General
Approach to acute poisoning, ECGs in Tox, Evidenced-based Tox, Toxicology literature summaries, Does anti-venom work?
Toxins / Overdose
Amphetamines, Barbituates, Benzylpiperazine, Beta Blockers, Calcium Channel Blocker, Carbamazepine, Carbon Monoxide, Ciguatera, Citrate, Clenbuterol, Cocaine, Corrosive ingestion, Cyanide, Digoxin, Ethanol, Ethylene Glycol, Iron, Isoniazid, Lithium, Local anaesthetic, Methanol, Monoamine oxidase inhibitor (MAOI), Mushrooms (non-hallucinogenic), Opioids, Organophosphate, Paracetamol, Paraquat, Plants, Polonium, Salicylate, Scombroid, Sodium channel blockers, Sodium valproate, Theophylline, Toxic alcohols, Tricyclic antidepressants (TCA)
Envenomation
Marine, Snakebite, Spider, Tick paralysis
Syndromes
Alcohol withdrawal, Anticholinergic syndrome, Cholinergic syndrome, Drug withdrawals in ICU, Hyperthermia associated toxidromes, Malignant hyperthermia (MH), Neuroleptic malignant syndrome (NMS), Opioid withdrawal, Propofol Infusion Syndrome (PrIS) Sedative toxidrome, Serotonin syndrome, Sympatholytic toxidrome, Sympathomimetic toxidrome
Decontamination
Activated Charcoal, Gastric lavage, GI Decontamination
Enhanced Elimination
Enhanced elimination, Hyperbaric therapy for CO
Antidotes
Antidote summary, Digibind, Glucagon, Flumazenil, HIET – High dose euglycaemic therapy, Intralipid, Methylene Blue, N-Acetylcysteine (NAC), Naloxone
Miscellaneous
Cocaine chest pain, Digoxin and stone heart theory, Hyperbaric oxygen, Hypoxaemia in tox, Liver failure in tox, Liver transplant for paracetamol, Methaemoglobinaemia, Urine drug screen
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
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