smooth muscle relaxant

aminophylline hydrate

Each 2 ml of solution contains Aminophylline Hydrate B.P. 500 mg equivalent to 479.45mg aminophylline.

Clear, sterile solution for injection, intended for parenteral administration to human beings.

Aminophylline is a complex of theophylline and ethylenediamine and is given for its theophylline activity to relax smooth muscle and to relieve bronchial spasm.

Aminophylline injection is indicated for relief of bronchospasm associated with asthma and in chronic obstructive pulmonary disease.

Aminophylline Injection B.P. 500mg/2ml is for deep intramuscular injection.

For adult patients, including the elderly, a single dose of 500mg (2ml) may be administered by deep intramuscular injection.

For maintenance therapy, Aminophylline Injection (intravenous) 250mg in 10ml can be administered via larger volume infusion solutions, rate-regulated to deliver the required amount of drug each hour.

Therapeutic plasma concentrations of theophylline are considered to be in the range of 5 to 20mcg/ml and levels above 20mcg/ml are more likely to be associated with toxic effects. There is marked interpatient variation in the dosage required to achieve plasma levels of theophylline that are within the desired therapeutic range.

During therapy, patients should be monitored carefully for signs of toxicity and, where possible, the serum theophylline levels should also be monitored.

Aminophylline Injection (intramuscular) 500mg in 2ml is not suitable for use in children.

Aminophylline should not be administered to patients with a known hypersensitivity to the xanthine group of drugs.

Elderly patients, or those with cardiac or hepatic disease should be monitored carefully for signs of theophylline toxicity. Children are particularly susceptible to the effects of theophylline and care is required when administrating aminophylline to children.

There have been reports of seizures in children with theophylline plasma levels within the accepted therapeutic range. Alternative treatment should be considered in patients with a history of seizure activity and, if Aminophylline Injection is used in such patients, they should be carefully observed for possible signs of central stimulation.

Because the mean half-life of theophylline is shorter in smokers than in nonsmokers, the former group may require larger doses of aminophylline.

To reduce the undesirable stimulating effects of aminophylline on the central nervous and cardiovascular systems, intravenous administration of the drug should be slow and should not exceed a rate of 25 mg/min.

Methylxanthines may increase gastric acidity and care should be taken when they are used in patients with a history of peptic ulceration.

Aminophylline should not be administered concurrently with other xanthine medications.

The label shall contain the following statements:-

Protect from light.

Store below 25°C.

If only part used discard the remaining solution.

Discard the ampoule if the contents are discoloured.

Increased serum levels of theophylline have been reported in patients who were also taking cimetidine, erythromycin, ciprofloxacin, allopurinol, thiabendazole, diltiazem or oral contraceptives. Factors such as viral infection or cardiac failure can also reduce theophylline clearance. There is an increased likelihood of toxicity occurring if ephedrine or other sympathomimetic agents are given concomitantly with aminophylline.

The concomitant use of theophylline and fluvoxamine should usually be avoided. Where this is not possible, patients should have their theophylline dose halved and plasma theophylline should be monitored closely. Factors such as cardiac failure or viral infection, including infection with influenza virus, can also reduce theophylline clearance.

Smoking can increase clearance of theophylline, as can carbamazepine, phenytoin, rifampicin and sulphinpyrazone.

Xanthines can potentiate hypokalaemia resulting from beta2 agonist therapy, steroids, diuretics and hypoxia. Particular caution is advised in severe asthma.

It is recommended that serum potassium levels are monitored in such situations.

Aminophylline may cause gastro-intestinal irritation, with nausea, vomiting and abdominal pain. Symptoms of central nervous system stimulation may occur, including insomnia, restlessness and anxiety. Theophylline can precipitate cardiac arrhythmias and hypotension may follow intravenous injection, particularly if the injection is too rapid. Allergic reactions to aminophylline may occur.

Mercury Pharma Group

(POM)

13 April 2012