Asthma pills like Synasma, Doxobid prices to drop to 1/12th their current prices in India

Doxovent, ZorDox , Doxoril are a few of other asthma pills to become cheaper.

Commonly used pills for asthma like Synasma and Doxobid would see their prices dropping to around 7 per cent of their current prices in India.

The Indian government is planning to reduce the prices of doxofylline – the active ingredient in asthma pills including Synasma and Doxobid – as the raw material cost of this drug is falling.

Doxofylline is currently not a price-controlled drug as it does not belong to essential medicine list under Drug Price Control Order 2005.

However, National Pharmaceutical Pricing Authority (NPPA), which is entitled to check prices of 74 drugs and their combinations coming under DPCO has decided to cut the prices of doxofylline because it is a derivative of another price-controlled drug theophylline used to treat asthma.

So, the price controlling authority has decided to fix the price of a doxofylline strip containing 10 tablets 400 mg each at Rs 5.74.

Currently, Doxobid 400-mg, manufactured by Dr Reddy’s Lab is sold  at Rs 78 for a strip of 10 tablets, and Ranbaxy’s Synasma 400-mg is priced at Rs 75.

These prices will come down drastically by around 100% once the price control on doxofylline comes into effect. The new prices are expected by this months itself.

Doxofylline (7-(1,3-dioxalan-2-ylmethyl) theophylline) is a novel xanthine bronchodilator which differs from theophylline in that it contains a dioxalane group in position 7. Similarly to theophylline, its mechanism of action is related to the inhibition of phosphodiesterase activities. The bronchodilating activities of doxofylline have been demonstrated in clinical trials involving patients with either bronchial asthma or chronic obstructive pulmonary disease. In contrast to other bronchodilators, experimental and clinical studies have shown that the drug is devoid of direct stimulatory effects. Doxofylline is indicated for chronic bronchitis, asthma and chronic obstructive pulmonary disease.

The half-life of doxofylline is greater than six hours. Single dose pharmacokinetic studies in man after oral and intravenous administration defined distribution and absorption of the drug.

After oral administration (tablets), peak plasma levels were reached after one hour. Absolute bioavailability is about 62.6%; at pH 7.4 plasma proteins binding the compound is about 48%. Less than 4% of an orally administered dose is excreted unchanged in the urine.

After i.v. administration of 100 mg to 5 healthy volunteers, distribution of doxofylline in plasma followed a bi-compartmental model.

Doxofylline is almost completely metabolized in the liver. Hydroxyethyltheophylline is the only detectable circulating metabolite of doxofylline.

After repeated administrations doxofylline reaches the steady-state in about 4 days; the elimination half-life during long-term treatment is 8-10 hours: this allows a twice daily dose regimen. No accumulation of the drug was noted after one week of treatment.

Drug makers have resorted to doxofylline to escape the price-control net, experts said. Though theophylline and doxofylline belong to the same therapeutic class, doxofylline is not considered as safe and effective as theophylline. Doxofylline is also not approved in several countries.

Ranbaxy Laboratories Limited in-licensed Synasma from  Netherlands-based Eurodrug Laboratories in 2006. Synasma is the first doxophylline product launched in India.

Other doxofylline formulations marketed in India includes Doxovent of Glenmark, ZorDox  of Cipla, Doxoril-400 of Macleods etc.

The asthma-related drug market in India is estimated to be around Rs 500 crore.