DILOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DILOR (DILOR).
DILOR (dyphylline) is a xanthine bronchodilator that inhibits phosphodiesterase, increasing intracellular cAMP levels, leading to relaxation of bronchial smooth muscle and suppression of airway responsiveness to stimuli. It also exhibits anti-inflammatory effects and enhances mucociliary clearance. Unlike theophylline, dyphylline is not converted to theophylline in vivo.
| Metabolism | Dyphylline is primarily metabolized by the liver via oxidation, with a smaller portion undergoing N-demethylation and oxidation. It is not metabolized to theophylline. Approximately 80% of the dose is excreted unchanged in the urine, indicating minimal hepatic metabolism. |
| Excretion | Renal: approximately 50% unchanged drug; biliary/fecal: minimal (less than 10%). The remainder undergoes hepatic metabolism. |
| Half-life | Terminal elimination half-life is 3-4 hours in adults; may be prolonged in neonates, elderly, and patients with hepatic or cardiac dysfunction. Theophylline is a narrow therapeutic index drug; half-life dictates dosing frequency and need for therapeutic drug monitoring. |
| Protein binding | Approximately 40% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.7 L/kg, approximating total body water; higher in neonates and patients with decreased protein binding (e.g., hepatic disease). |
| Bioavailability | Oral immediate-release: 100% (well absorbed); Extended-release formulations have comparable bioavailability with slower absorption. |
| Onset of Action | Oral (immediate-release): 30-60 minutes; Oral (extended-release): 2-4 hours; Intravenous: rapid (within minutes). |
| Duration of Action | Immediate-release oral: 4-6 hours; Extended-release oral: 8-12 hours or up to 24 hours depending on formulation; Intravenous: dose-dependent, typically 4-6 hours. Duration is influenced by rate of metabolism and elimination. |
DILOR (Dyphylline) 200-400 mg orally every 6 hours; maximum 1.6 g/day. Also available as IM injection: 250-500 mg every 6 hours.
| Dosage form | TABLET |
| Renal impairment | CrCl 50-80 mL/min: 75% of dose; CrCl 25-50 mL/min: 50% of dose; CrCl <25 mL/min: 25% of dose; hemodialysis: administer after dialysis at 50% of dose. |
| Liver impairment | No specific Child-Pugh based adjustments established; use with caution in severe hepatic impairment due to potential reduced clearance. |
| Pediatric use | Not recommended for use in children; safety and efficacy not established. If used: 3-5 mg/kg orally every 6 hours, titrate to serum levels. |
| Geriatric use | Start at lower end of dosing (200 mg every 6 hours) due to potential age-related decline in renal function; monitor serum levels and adjust based on CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DILOR (DILOR).
| Breastfeeding | Diprophylline is excreted into human milk. The M/P ratio is unknown. Potential adverse effects in infants include irritability and poor feeding. Weigh benefits against risks. Consider alternative bronchodilators if possible. |
| Teratogenic Risk | DILOR (diprophylline) is a xanthine derivative. Animal studies have not shown teratogenic effects. There are no adequate and well-controlled studies in pregnant women. Risk cannot be ruled out. Fetal risks are considered low, but caution is advised during all trimesters. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to dyphylline or any component of the formulation; history of seizure disorder (unless adequately controlled); active gastrointestinal hemorrhage; concurrent use of other xanthine derivatives (e.g., theophylline, caffeine).
| Precautions | Use with caution in patients with peptic ulcer disease, hyperthyroidism, glaucoma, diabetes mellitus, severe hypoxemia, hypertension, arrhythmias, congestive heart failure, and renal impairment. Monitor serum levels; toxicity can occur at high doses. Concurrent use with other xanthines may increase toxicity. May cause seizures, arrhythmias, and death if serum levels exceed the therapeutic range. |
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| Fetal Monitoring |
| Monitor maternal serum theophylline levels (if applicable) and clinical response. Fetal heart rate monitoring may be considered in preterm labor or high doses due to potential maternal tachycardia. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data are insufficient. |