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Theophylline; Uses, Dosage, Side effects, Drug Interactions

Theophylline is a natural alkaloid derivative of xanthine isolated from the plants Camellia sinensis and Coffea arabica. Theophylline appears to inhibit phosphodiesterase and prostaglandin production, regulate calcium flux and intracellular calcium distribution, and antagonize adenosine. Physiologically, this agent relaxes bronchial smooth muscle, produces vasodilation (except in cerebral vessels), stimulates the CNS, stimulates cardiac muscle, induces diuresis, and increases gastric acid secretion; it may also suppress inflammation and improve contractility of the diaphragm.

A methylxanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Mechanistically, theophylline acts as a phosphodiesterase inhibitor, adenosine receptor blocker, and histone deacetylase activator. As a member of the xanthine family, it bears structural and pharmacological similarity to theobromine and caffeine, and is readily found in nature, and is present in tea (Camellia sinensis) and cocoa (Theobroma cacao). A small amount of theophylline is one of the products of caffeine metabolic processing in the liver.

Mechanism of action of theophylline

Theophylline relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels and reduces airway responsiveness to histamine, methacholine, adenosine, and allergen. Theophylline competitively inhibits type III and type IV phosphodiesterase (PDE), the enzyme responsible for breaking down cyclic AMP in smooth muscle cells, possibly resulting in bronchodilation. Theophylline also binds to the adenosine A2B receptor and blocks adenosine mediated bronchoconstriction. In inflammatory states, theophylline activates histone deacetylase to prevent transcription of inflammatory genes that require the acetylation of histones for transcription to begin.

Indications of theophylline

Apnea of prematurity
Asthma, acute
Asthma, maintenance
Relaxing bronchial smooth muscle
Increasing heart muscle contractility and efficiency; as a positive inotrope
Increasing heart rate: (positive chronotropic)
Increasing blood pressure
Central nervous system stimulatory effect mainly on the medullary respiratory center.
Chronic obstructive pulmonary disease (COPD)
Asthma
Infant apnea
Blocks the action of adenosine; an inhibitory neurotransmitter that induces sleep, contracts the smooth muscles and relaxes the cardiac muscle.
For the treatment of the symptoms and reversible airflow obstruction associated with chronic asthma and other chronic lung diseases, such as emphysema and chronic bronchitis.

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Contra Indications of theophylline

Overactive thyroid gland
Hypothyroidism
Diabetes
Cystic Fibrosis
High blood pressure
Heart attack
Angina
Chronic heart failure
Fluid in the Lungs
Ulcer from Stomach Acid
Acute inflammation of the liver
Liver problems
Seizures
Fever for Many Days
Fast Heartbeat
Shock
Sepsis Syndrome
Third trimester of pregnancy
Tobacco smoking
Stop Smoking
Poisoning by Breathing Drug Theophylline
Multiple Organ Failure
Chronic Cannabis Smoker

Dosages of theophylline

Strengths: 100 mg; 200 mg; 400 mg/24 hours; 600 mg/24 hours; 125 mg; 300 mg; 450 mg;

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.

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.

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;

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.

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
Full term infants: Total daily dose (mg) = [(0.2 x age in weeks) +5] x (weight in kg); divide dose into 3 equal amounts and administer at 8 hour intervals

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Side Effects of theophylline

The most common

Common

Less common

Abdominal or stomach pain
general feeling of discomfort or illness
headache
joint pain
pain or tenderness around the eyes and cheekbones
shortness of breath or troubled breathing
sweating
tightness of the chest

Drug Interactions of theophylline

Theophylline may interact with following drugs,suppliment & may change the efficacy of drugs

antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine,risperidone)
antiseizure medications (e.g., clobazam, phenobarbital, phenytoin, valproic acid, )
aripiprazole
“azole” antifungals (e.g., itraconazole, ketoconazole, voriconazole)
baclofen
barbiturates (e.g., butalbital, pentobarbital, phenobarbital)
benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
Calcium channel blockers, diltiazem, verapamil
domperidone
famotidine
gabapentin
ipratropium
ketotifen
levodopa
macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
magnesium sulfate
methylphenidate
mirtazapine
Methotrexate
monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, rasagiline, selegiline,tranylcypromine)
quinolone antibiotics (e.g., levofloxacin, norfloxacin, moxifloxacin)
selective serotonin reuptake inhibitors (SSRIs; e.g., paroxetine, fluoxetine, citalopram)
serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
sotalol
tapentadol
thiazide diuretics (water pills; e.g., hydrochlorothiazide, indapamide, )
thioridazine
tolterodine
tramadol
trimethoprim
tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
“triptan” migraine medications (e.g., eletriptan, sumatriptan)
tryptophan
tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib, sunitinib)
Zafirlukast

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Pregnancy & Lactation of theophylline

FDA Pregnancy Category B

Pregnancy

This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding

It is not known if orciprenaline passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.