Pfizer (India) Ltd is launching its over $1 billion anti-depressant brand Zoloft under the brand name Daxid in India this week, a company source confirmed. The brand name has been changed to avoid parallel marketing of the product in areas where the main brand is being sold, it is learnt.

An industry analyst welcomed the development and said that with Pfizer''s aggressive marketing strategies, the product can gain good acceptance here. But what is not sure is whether Pfizer will be able to match the prices offered by the Indian generics makers.

Several brands of the compound are being marketed in India by 13 companies which include RLL subsidiary Solus (brand Serlift), Unichem Laboratories Ltd (Serta), Sun Pharmaceutical Industries Ltd (Zosert), Alkem Laboratories Ltd (Tralin), Protec (Serdep), Nicholas Piramal India Ltd (Asert), Torrent (Serenata), and Sarabhai Piramal''s Sertil.

According to a retail market sources, the sertraline hydrochloride market is worth Rs 26.02 crore, and is growing at a rate of just 4.8 per cent.

Serlift enjoys five per cent of the anti-depressant market share, closely followed by Serta with a four per cent share while Zosert has 2.3 per cent of the market revenues.

The compound got quick acceptance in India after its introduction over an year ago in the Indian market. According to an industry source, the sertraline market is already depressed due to price cuts and severe competition. One more entrant will not make any difference to the situation, she said.

Zoloft is sertraline hydrochloride, coming in the class of selective serotonin reuptake inhibitors (SSRIs). Serotonin is a naturally occurring chemical in the brain that is involved in the transmission of messages between nerve cells.

Although the way sertraline hydrochloride works for depression, panic disorder, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD) is not completely understood, what is understood is that sertraline hydrochloride is a medicine that helps correct the chemical imbalance of serotonin in the brain. Normally serotonin is released from one nerve cell and picked up by the other nerve cell. Some of this serotonin is taken back by the first nerve cell. In depressed people, the nerve cells are unable to interact properly.

The antidepressant effect of sertraline is presumed to be linked to its ability to inhibit the neuronal reuptake of serotonin. At clinical doses, sertraline blocks the uptake of serotonin into human platelets.

Patients may start to feel better within 2 to 4 weeks or it may take as long as 6 to 8 weeks. In medical studies, it has been shown that sertraline hydrochloride is not addictive or habit-forming.

The US FDA had approved sertraline hydrochloride for the treatment of depression, panic disorder, OCD, and PTSD.

The most common side effects include upset stomach, troubled sleeping, diarrhoea, dry mouth, sexual side effects, feeling unusually sleepy or tired, tremor, indigestion, increase of sweating, feeling agitated, and decreased appetite.