The stock slipped 8.67 per cent to settle at Rs 1,760.80 on BSE. During the day, it tumbled 9 per cent to Rs 1,753.10.
At NSE, shares of the company dived 8.99 per cent to close at Rs 1,754.70.
The company's market valuation fell by Rs 763.74 crore to Rs 8,055.26 crore.
Pfizer has discontinued manufacture and sale of Corex cough syrup with immediate effect after the government banned fixed dose combination of Chlopheniramine Maleate+ Codeine Syrup.
In view of this, the company has discontinued the manufacture and sale of the drug with immediate effect, it said.
"The above prohibition is likely to have an adverse impact on the revenue and profitability of the company... Corex recorded sale of Rs 176 crore for the nine month period ended December 31, 2015," the company said.