Drug information of Theophyline

Theophyline

Drug group:

Theophylline is a bronchodilator that relaxes the chest and lung muscles for better breathing and reduces the sensitivity of bronchial tubes to allergens and other bronchospasm agents. It is also used to treat wheezing and shortness of breath and symptoms of asthma, bronchitis, emphysema and other respiratory problems.

Theophylline is structurally classified as a methyl xanthine  that you can see the structure of anhydrous form.

Mechanism of effect

Theophyllin increase intracellular CAMP and effects the smooth muscle of the respiratory and pulmonary arteries so reduces the spasm of the bronchus and increases the velocity of air flow and vital capacity.

Pharmacokinetics

Theophylline is rapidly and completely absorbed after oral administration in solution or immediate-release solid oral dosage form. After a single dose immediate release Theophylline of 5 mg/kg in adults, a mean peak serum concentration of about 10 mcg/mL (range 5-15 mcg/mL) can be expected 1-2 hour after the dose.

 Co-administration of Theophylline with food or antacids does not cause clinically significant changes in the absorption of Theophylline from immediate-release dosage forms.

Theophylline does not undergo any appreciable pre-systemic elimination, distributes freely into fat-free tissues and is extensively metabolized in the liver. ActuallyIn adults and children beyond one year of age, approximately 90% of the dose is metabolized in the liver.

The pharmacokinetics of Theophylline vary widely among similar patients and cannot be predicted by age, sex, body weight or other demographic characteristics. In addition, certain concurrent illnesses and alterations in normal physiology and co-administration of other drugs can significantly alter the pharmacokinetic characteristics of Theophylline.

Excretion: Since little Theophylline is excreted unchanged in the urine and since active metabolites of Theophylline (i.e., caffeine, 3-methylxanthine) do not accumulate to clinically significant levels even in the face of end-stage renal disease, no dosage adjustment for renal insufficiency is necessary in adults and children >3 months of age. In contrast, the large fraction of the Theophylline dose excreted in the urine as unchanged Theophylline and caffeine in neonates requires careful attention to dose reduction and frequent monitoring of serum Theophylline concentrations in neonates with reduced renal function.

Hepatic Insufficiency: Theophylline clearance is decreased by 50% or more in patients with hepatic insufficiency (e.g., cirrhosis, acute hepatitis, cholestasis). Careful attention to dose reduction and frequent monitoring of serum Theophylline concentrations are required in patients with reduced hepatic function

Dosage

Usual Adult Dose for Asthma - Acute

Loading dose: 5 mg/kg loading dose (patient not receiving theophylline or aminophylline).

Maintenance dose:


Otherwise Healthy Nonsmoking Adult: 10 mg/kg/day. Do not exceed 900 mg/day.

Otherwise Healthy Adult Smoker: 16 mg/kg/day.

Patient with congestive heart failure or cor pulmonale: 5 mg/kg/day. Do not exceed 400 mg/day.

Usual Adult Dose for Asthma - Maintenance

Loading dose: 5 mg/kg loading dose (patient not receiving theophylline or aminophylline).

Maintenance dose:

Otherwise Healthy Nonsmoking Adult: 10 mg/kg/day. Do not exceed 900 mg/day.

Otherwise Healthy Adult Smoker: 16 mg/kg/day.

Patient with congestive heart failure or cor pulmonale: 5 mg/kg/day. Do not exceed 400 mg/day.

 

Usual Pediatric Dose for Asthma - Acute

Loading dose:
If no theophylline has been administered in the previous 24 hours: 5 mg/kg loading dose to achieve a serum concentration of about 10 mcg/mL; loading doses should be given using a rapidly absorbed oral product not a sustained release product).

If theophylline has been administered in the previous 24 hours: 2.5 mg/kg theophylline may be given in emergencies when serum concentrations are not available. A modified loading dose (mg/kg) may be calculated (when the serum level is known) by: [Blood concentration desired - blood concentration measured] divided by 2 (for every 1 mg/kg theophylline given, the blood level will rise by approximately 2 mcg/mL).

Maintenance dose:

less than 42 days: 4 mg/kg/day orally.

42 days to 181 days: 10 mg/kg/day orally. Alternate dosing: [(0.2 x age in weeks) + 5] x kg = 24 hour oral dose in milligrams.

6 months less than 12 months: 12 to 18 mg/kg/day. Alternate dosing: [(0.2 x age in weeks) + 5] x kg = 24 hour oral dose in milligrams.

1 year to 8 years: 20 to 24 mg/kg/day.

9 years to 11 years: 16 mg/kg/day.

12 years to 15 years: 13 mg/kg/day.

16 years or older: 10 mg/kg/day. Do not exceed 900 mg/day.

Usual Pediatric Dose for Asthma - Maintenance

Loading dose:
If no theophylline has been administered in the previous 24 hours: 5 mg/kg loading dose to achieve a serum concentration of about 10 mcg/mL; loading doses should be given using a rapidly absorbed oral product not a sustained release product).

If theophylline has been administered in the previous 24 hours: 2.5 mg/kg theophylline may be given in emergencies when serum concentrations are not available. A modified loading dose (mg/kg) may be calculated (when the serum level is known) by: [Blood concentration desired - blood concentration measured] divided by 2 (for every 1 mg/kg theophylline given, the blood level will rise by approximately 2 mcg/mL).

Maintenance dose:

less than 42 days: 4 mg/kg/day orally.

42 days to 181 days: 10 mg/kg/day orally. Alternate dosing: [(0.2 x age in weeks) + 5] x kg = 24 hour oral dose in milligrams.

6 months less than 12 months: 12 to 18 mg/kg/day. Alternate dosing: [(0.2 x age in weeks) + 5] x kg = 24 hour oral dose in milligrams.

1 year to 8 years: 20 to 24 mg/kg/day.

9 years to 11 years: 16 mg/kg/day.

12 years to 15 years: 13 mg/kg/day.

16 years or older: 10 mg/kg/day. Do not exceed 900 mg/day.

Usual Pediatric Dose for Apnea of Prematurity

Manufacturer recommendations:
Loading dose: 4.6 mg/kg/dose
Maintenance:
Premature neonates: Post natal age less than 24 days: 1 mg/kg/dose every 12 hours
Premature neonates: Post natal age 24 or more days: 1.5 mg/kg/dose every 12 hours

Drug contraindications

hypersensitivity to this drug

Pregnancy level

C


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