Patient with stable angina was used nitroglycerin wich develope nitroglycerin tolerance , how can prevent it ?

Prevention of Nitroglycerin Tolerance is by providing a nitrate-free interval  ( time of absence of nitrates in the body )each day : 

if the patient is using short-acting preparation : the last dose should be no later than7 pm to allow of- hours of nitrate-free period  AND the frequency of dosing should be2-3 times/day not4 times/day

if the patient is using long-acting preparation : the frequency is twice a day so the recommendation will be to take the1st dose foe example  at8 am , the second at2 pm to allow - hours of free interval of nitrates

the exact time should be suitable for the patient lifestyle. 

In addition vitamin C can help in the prophylaxis of Nitrate tolerance.