Other Xanthines
Severe
Database
Additive cardiac/CNS toxicity
Avoid combination
Source: Kimi deep-research + Cla
Drug reference
doxofylline
Methylxanthine bronchodilator (dioxolane analog) · Bronchodilator
START
400 mg PO 2–3 times daily after food
TYPICAL MAX
1200 mg/day
STOP IF
Significant arrhythmia, seizure, or severe hypotension
WATCH
ECG/HR, K, GI symptoms; xanthine-class CNS effects
CDSCO approvedATC R03DA11
KDIGO 2024 + manufacturer label
- ONSET
- 45min · absorption
- PEAK
- 1h · Tmax
- t½
- 6.5h · t½
- DURATION
- 12h · BID-TID
EXCRETION
Renal — metabolites; ~4% unchanged
route + CYP
INTERACTIONS
1 major
SEVERE in our sources
PREGNANCY
Limited data; use only if clearly needed.
FDA category + note
Top interactionssee all 12 →
- Other XanthinesSevereDatabaseKimi deep-research + Cla
Mechanism
Methylxanthine that inhibits phosphodiesterase III/IV (less adenosine antagonism than theophylline), producing bronchodilation; lower CNS / cardiac toxicity than theophylline.
Indications
Chronic obstructive pulmonary diseaseAsthma (maintenance, regions where licensed)
Dosing
- Adult
- 400 mg PO 2–3 times daily after food.
- Pediatric
- ≥12 y: as adult.
- Renal adjustment
- Caution in severe impairment; no fixed adjustment.
- Hepatic adjustment
- Reduce dose in significant impairment.
- Geriatric
- Reduce dose; tachyarrhythmia risk.
- Max dose
- 1200 mg/day
Pharmacokinetics
Onset
Bronchodilation 30–60 min
Peak effect
~1 h (Tmax)
Duration
~12 h
Half-life
~6–7 h
Bioavailability
Well absorbed orally
Protein binding
~48%
Metabolism
Hepatic
Excretion
Renal (metabolites; ~4% unchanged)
Contraindications
- Acute myocardial infarction
- Severe arrhythmia
- Severe hypotension
- Hypersensitivity to xanthines
- Caution: peptic ulcer, seizure disorders
Side effects
Common
Nausea/vomitingHeadachePalpitationsInsomniaTremor
Serious
- Tachyarrhythmia
- Seizures (overdose)
- Severe hypotension
- GI bleeding (rare)
Pregnancy & lactation
Pregnancy
Limited data; use only if clearly needed.
Lactation
Limited data; caution.
Drug interactions
Allopurinol
Moderate
Database
Increased plasma concentrations of doxofylline, leading to an increased risk of adverse effects.
Monitor for increased doxofylline adverse effects. Consider a doxofylline dose reduction, especially with higher doses of allopurinol.
Cimetidine
Moderate
Database
Increased plasma concentrations of doxofylline, leading to an increased risk of adverse effects such as nausea, vomiting, headache, and CNS stimulation.
Monitor for increased doxofylline adverse effects. Consider a doxofylline dose reduction or choose an alternative H2-receptor antagonist (e.g., ranitidine, famotidine) that has less CYP inhibition.
Ciprofloxacin
Moderate
Database
Increased xanthine levels
Monitor; reduce dose
Source: Kimi deep-research + Cla
Beta Blockers
Moderate
Database
Antagonism of bronchodilation
Use cardioselective β-blocker if needed
Source: Kimi deep-research + Cla
Erythromycin
Moderate
Database
Increased plasma concentrations of doxofylline, potentially leading to enhanced therapeutic effects and an increased risk of adverse reactions.
Monitor for increased doxofylline adverse effects. Consider a doxofylline dose reduction or choose an alternative macrolide antibiotic (e.g., azithromycin) with less CYP inhibition.
Fluvoxamine
Moderate
Database
Significantly increased plasma concentrations of doxofylline, leading to an increased risk of adverse effects such as nausea, vomiting, headache, and CNS stimulation.
Avoid concomitant use if possible. If co-administration is necessary, significantly reduce the doxofylline dose and closely monitor for adverse effects. Consider an alternative antidepressant.
Lithium
Moderate
Database
Increased lithium clearance
Monitor lithium levels
Source: Kimi deep-research + Cla
Phenobarbital
Moderate
Database
Decreased plasma concentrations of doxofylline, potentially leading to reduced therapeutic efficacy.
Monitor for reduced doxofylline efficacy. An increase in doxofylline dose may be required. Close monitoring is essential, especially when phenobarbital is initiated or discontinued.
Phenytoin
Moderate
Database
Decreased plasma concentrations of doxofylline, potentially leading to reduced therapeutic efficacy.
Monitor for reduced doxofylline efficacy. An increase in doxofylline dose may be required. Close monitoring is essential, especially when phenytoin is initiated or discontinued.
Propranolol
Moderate
Database
Increased plasma concentrations of doxofylline, leading to an increased risk of adverse effects.
Monitor for increased doxofylline adverse effects. Consider a doxofylline dose reduction. If possible, consider an alternative beta-blocker with less CYP inhibition.
Rifampicin
Moderate
Database
Decreased plasma concentrations of doxofylline, potentially leading to reduced therapeutic efficacy.
Monitor for reduced doxofylline efficacy. An increase in doxofylline dose may be required. Close monitoring is essential, especially when rifampicin is initiated or discontinued.
Related guidelines
Ask House about doxofylline
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: Goodman & Gilman 14e·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20