SUNANDA PUSHKAR , wife of Shri SHASHI THARUR death seems due to  habitual and continuous sedative drug intake resistance  and sedative drug’s compulsory physical side effects reaction on human body Homeostatistically and  sudden functional paralysis of respiratory organs, which causes the death of Sunanda Pushkar,
I assume without any doubt that there may be more causes relted to the Physiology of human body, but in my opinion Sunanda Death is natural and due to reaction of drugs, as I have mentioned above.
Hypnotics and Anxiolytic Drugs acts on the Nervous System mainly. but refelection of the alkeloids actions affects whole body and thus more systems of body physiology is changed.
Pharmacological books mentions that drugs action on Nervous system anomalies treatment , certain group of remedies like  Hypnotis and Anxiolytics drugs and  Schizophrenia and behavioural emergencies drugs and  Mood disorders drugs can cause sudden death during sleep.
I am not in any way concerned to Mr. Shashi Tharura, nor I met him ever, I have seen him on TV and in News papers and read about the death of his life-partner Mrs Sunanda Pushkar. What I had perceived and have concluded the circumstances of death scenario are totally based on according to my experience after seeing the similar condition of patient’s death who were taking like drugs for long periods, I presume that possibilities of the death condition may be similar due to inimical drug actions, as I have said earlier.