Side effects of Milk of the Poppy
Milk of the Poppy indeed helps with the pain but it has very dire side effects if taken over a long period.
- It can distress the patient with disturbing dreams.
- It can dull the mind of the in-taker to an incapacitating effect.
- It can affect appearance of the in-taker's face i.e. making it puffy.
- Body may develop tolerance of the medicine, thus requiring even bigger doses with that much more side effects.
- It can be addictive
- It can undermine efficiency of certain anti-infection medicines.
This is why some people prefer to bear the pain instead of going on Milk of the Poppy. King Aegon II's reaction to treatment by MOP after his second injuries taken against Lady Baela Targaryen was:
I shall not walk that road again.
The King was completely incapacitated due to MOP and regency passed to his rash brother Aemond, who made a string of mistakes which resulted in fall of King's Landing, Arrest of Queen Mother and Queen Consort, Death of Queen Consort and near-arrest of the King along with his Children. Aegon did not wish to let it happen ever again.
People who accepted Milk of the Poppy
- Rhaenyra Targaryen took milk of the poppy after stillborn birth of her daughter Visenya.
- King Aegon II took milk of the poppy after his battle with Princess Rhaenys 'Queen who never was' Targaryen.
- Lord Balon Greyjoy's father, Lord Quellon Greyjoy used to take milk of the poppy for his stomach aches during his old age every night.
- Milk of the Poppy was administered to Jon Arryn by Grand Maester Pycelle.
- Eddard Stark was given milk of the Poppy by Grand Maester Pycelle.
- Robert Baratheon took milk of the poppy after dictating his will to Eddard Stark.
- Jon Snow was given milk of the poppy by Maester Aemon after his fight against Wights in Lord Commander's Tower.
- Lord Hoster Tully was given Milk of the poppy by Maester Vyman for his stomach aches.
- Tyrion Lannister was given milk of the poppy after his injuries in Battle of Blackwater Bay.
- Prince Doran Martell takes milk of the poppy to dull his gout induced pain.
- Gregor Cleagane used to take a lot of MOP for his injuries taken against Prince Oberyn Martell.
- Quentyn Martell was given MOP by Missandei after he got burnt by Dragons.
- Khal Drogo drank poppy wine despite being warned of its impacts on anti-biotic treatment he had received for his wound. The wound festered as a result and Khal died.
People who refused Milk of the Poppy
- Jaime Lannister refused milk of the poppy however it was not due to fear of side-effects. Jaime was afraid that Qyburn would cut his whole arm if he let himself be knocked out by MOP.
People who refused further treatment on milk of the poppy
King Aegon II refused another MOP treatment when he sustained new injuries against Baela Targaryen. King was determined not to walk that road again and lived rest of his life in pain.
Tyrion Lannister refused further treatment on milk of the poppy after Blackwater Bay.
People who occasionally refused milk of the poppy
- Prince Doran Martell refused milk of the poppy once before meeting his nieces as he wanted to keep a clear head in the meeting given sinister reputation of his nieces.
People who became addicted/tolerant to milk of the poppy
- Gregor Cleagane used to drink milk of poppy like other people drink ale. This made him both dependent on and tolerant of milk of the poppy.
So as you can see, there is only once instance of a character refusing to take Milk of the poppy without ever have taken it before. That's Jaime.