What are meant by Essential Medicines?

Answer: Essential medicines are those that satisfy the priority health care needs of the population. They are defined by the World Health Organization (WHO) are those drugs that satisfy the health care needs of the majority of the population; they should therefore be available at all times in adequate amounts and in appropriate dosage forms, at a price the individual and community can afford. They are selected with due regard to public health relevance, evidence on efficacy and safety, and comparative cost-effectiveness.

Essential medicines lists have been shown to improve the quality and cost-effectiveness of health care delivery when combined with proper procurement policies and good prescribing practices. The WHO has published a model list of essential medicines. Each country is encouraged to prepare their own lists taking into consideration local priorities. Over 150 countries have published an official essential medicines list. The essential medicines list enables health authorities, especially in developing countries, to optimize pharmaceutical resources.
The Ministry of Health, Government of India had revised the National List of Essential Medicines of India (NLEMI 2011) in June 2011 and soon shall introduce some new drugs.
To catch hold, the previous list of essential medicines follow, http://pharmaceuticals.gov.in/nlem.pdf

Q2. What is meant by Iatrogenesis?

Answer: Iatrogenesis (from the Greek for "brought forth by the healer") refers to any effect on a person, resulting from any activity of one or more persons acting as healthcare professionals or promoting products or services as beneficial to health, that does not support a goal of the person affected. Some iatrogenic effects are clearly defined and easily recognized, such as a complication following a surgical procedure (e.g. Lymphedema as a result of breast cancer surgery) and some are unpredictable such as complex drug interactions which may require significant investigation to detect.

Causes of iatrogenesis include side effects of possible drug interactions, medical error, wrong prescription dispensing possibly due to illegible handwriting, typos on compute negligence, unexamined instrument design ,anxiety or annoyance in the physician or treatment provider in relation to medical procedures or treatments or unnecessary treatment for profit.

Professionals like physicians, pharmacists, nurses, dentists, psychologists, and therapists can be the cause of iatrogenic effect. Iatrogenesis can also result from complementary and alternative medicine treatments.