All medicines have a therapeutic range which differs according to age, lean body weight, liver function, kidney function etc. Dosages below this therapeutic range would be too low to cause any (pharmacological) effect while over-dosage above this range would be toxic (i.e. poisonous) causing potential harm. The majority of modern medicines fall into this category & it is not unique to them, rather we see that many of the Prophetic Medicines likewise follow this pattern such as black seed oil which if taken in overdose causes liver damage. Hence the need to return dosages back to those who are specialised in the field.
Minerals, Electrolytes & Vitamins
In fact many minerals, electrolytes & vitamins that are essential to the human body likewise follows the same pattern. For example, table salt is primarily made from a chemical compound called ‘sodium chloride’ that is needed for the human body to function correctly, yet too little results in illness & possible coma while too much results in poisoning & death. However only an individual who was pursuing a particular agenda would describe salt as poisonous and this is likewise the case for modern medicines.
There are a very small percentage of specialised medicines that are usually initiated by specialised doctors for very serious illnesses that require frequent monitoring while within the therapeutic range. This is principally due to every patient not having the same response to that specialised medicine and in some cases if can result in a harmful adverse effect. However these adverse effects are known & actively monitored by one means or another to ensure if they are starting to occur then the medicine is reduced, stopped or another medicine is use to counteract that adverse effect. Further, the specialist will discuss these potential risks prior to initiating such medicine & the patient will consent to such risks, however the specialist will only agree to initiating such a medicine if they believe that the potential benefits out weigh any potential harm. So again I say, only an individual who was pursuing a particular agenda would describe modern medicines, in general, as poisonous.
The statements of the individual who describes modern medicines as poisonous is discussed at length here.