Norphyl belongs to a group of medicines known as methylxanthine bronchodilators. It is a combined drug of theophylline and ethylenediamine. Ethylenediamine is an inactive agent that increases the solubility of theophylline in water. Theophylline relaxes the smooth muscle of the respiratory tract.
Thus, this drug combination relieves respiratory symptoms such as:
Troubled breathing by increasing the flow of air through the air passages
That’s why this medicine is widely prescribed to treat asthma, acute bronchospasm, chronic bronchitis, and emphysema. It also increases contraction of the diaphragm by increasing calcium uptake through chemical channels.
Aminophylline is often used in combination with selective beta-2 agonists, and oral or intravenous steroids for the management of acute severe asthma and chronic obstructive pulmonary disease (COPD).
Aminophylline is administered intravenously along with other drugs to treat the acute symptoms of acute severe asthma i.e. status asthmaticus, bronchitis, emphysema, and other respiratory ailments in a hospital setting. You cannot get this medicine without your doctor's prescription.
2 What to Know Before Using
Before using Norphyl, you must know all about the risks and complications associated with it. This is a decision that your doctor will make with your active participation.
There are some important factors such as drug interaction, metabolic impairment, hypersensitivity reaction, pregnancy, lactation etc. which may alter the drug action.
Theophylline is extensively metabolized in the liver by demethylation and oxidation process. There are marked variations of plasma concentrations in different individuals that are attained with the same dose.
Its elimination from the body varies considerably with age. At therapeutic concentrations, children eliminate it much faster and elderly more slowly.
Theophylline metabolizing enzymes being saturated prolong the half-life significantly may be up to 60 hours when given at higher doses. This drug is well distributed in all tissues. It crosses the placenta and may affect the fetus.
Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
To use Norphyl properly, you must follow all instructions given by your doctor. The dose of this medicine will vary according to patient’s condition or requirements.
You should follow the doctor's directions and advice. The amount of medicine that you take should not exceed the maximum therapeutic dose.
Also, the frequency of your daily drug administration and the duration of drug therapy depend on the particular medical problem for which you are taking the medicine.
Therapeutic intravenous administration is often prescribed to treat following health disorders:
Bronchial asthma and COPD: theophylline benefits by causing bronchodilatation as well as presumably by decreasing the release of inflammatory mediators, improved mucociliary clearance, stimulation of respiratory drive and by augmenting diaphragmatic contractility.
However, because of the narrow margin of safety and limited efficacy, its use has declined. Use of intravenous aminophylline in status asthmaticus is outmoded.
Chronic bronchospasm is usually treated with 225-450 mg aminophylline taken orally twice a day. The therapeutic dose can be increased if necessary.
Oral theophylline is often used to treat mild-to-moderately severe asthma, as a 3rd line or alternative adjuvant drug, especially in patients with nocturnal asthma.
Apnoea in the premature infant: theophylline reduces the frequency and duration of episodes of apnoea that occur in some preterm infants in the first few weeks of life.
Closely monitored oral or intravenous administration of aminophylline is employed for 1-3 weeks.
Always try to take your medicine in time. If you miss any dose of this medicine, you should take it as soon as possible. But when it is time for your next dose, then skip the missed dose and go back to your regular dosing schedule.
You should store the medicine in a closed container at room temperature away from heat, moisture, and direct light.
4 Precautions to Take
Before using Norphyl, there are some precautions you must take. Regular visits are recommended to make sure this medicine is working properly or not while you are undergoing aminophylline therapy.
Some important measures should be taken if you feel any discomfort following this drug therapy. You should tell your doctor if you are allergic to such medications or any other medicines.
Certain drugs should not be used concurrently with such medications. It is always recommended to consult with your doctor if you are in need of some drugs for another health problem.
You should not take the following drugs during aminophylline therapy in order to get rid of drug reactions:
Smoking, rifampicin, phenytoin, phenobarbitone, charcoal and boiled meat meal induce theophylline metabolism and decrease its plasma level.
Erythromycin, ciprofloxacin, cimetidine, oral contraceptives and allopurinol are the drugs which inhibit theophylline metabolism and increase its plasma level.
Theophylline enhances the effects of some drugs like furosemide, sympathomimetics, digitalis, oral anti-coagulants and hypoglycaemics. So, these drugs should be taken cautiously while you are receiving aminoplylline.
Theophylline decreases the effects of phenytoin and lithium. For this reason, you cannot get the desired effect of such medications while undergoing aminophylline therapy.
Aminophylline injection should not be mixed in the same infusion bottle or syringe with ascorbic acid, chlorpromazine, promethazine, morphine, pethidine, phenytoin, phenobarbitone, insulin, penicillin G, tetracyclines, and erythromycin.
5 Potential Side Effects
Make sure you meet with your doctor in using Norphyl to avoid unwanted potential side effects. There are some unwanted side-effects associated with each drug that usually do not need medical attention. The adverse effects are primarily related to the GIT, CNS, and CVS. Children are more vulnerable to develop CNS toxicity.
Some common side effects of aminophylline are gastric irritation, headache, nausea, vomiting, diarrhea, insomnia, irritability, restlessness, seizures, tremors, irregular heart rhythms, increased heart rate, and scaly skin.
These side-effects usually go away during the treatment episode as your body adjusts to the medicine. Additionally, your health care professional may advise you about the ways how to prevent or reduce those unwanted side-effects.
Sometimes you may need to consult with the doctor if you feel any serious toxic effect. The rapid intravenous injection may cause precordial pain, syncope, ventricular arrhythmias and even sudden death due to marked fall in blood pressure.
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