Is it okay not to take antihypertensive drugs if the blood pressure is normal even though the drugs is a maintenance for high blood pressure?

Donot stop. Tit-ration of medicines if need due to a persistently low BP is recommended . closely follow your local physicians advise This is long term treatment for BP.
Take medications. Medications need to be taken as prescribed to control hypertension. Stopping and starting medications can be dangerous. If your blood pressures are normal then that means that your medications are working and you need to take them daily. If you have symptoms of low blood pressure like dizziness or if your blood pressures are consistently low see your doctor for medication adjustments.
Blood pressure. This is a challenging question. Sometimes medications are for 'blood pressure' but are also used for other purposes well. For example, someone with heart failure of diabetes may take a certain medication called an ACE-Inhibitor because they can be helpful in other ways besides blood pressure. Please check in with your doctor and bring a blood pressure log in to your next appointment.
Perhaps. If you or your best friend regularly check the BP and it is within normal range. Twice DAILY and every day! Report the findings to your PCP or hypertension MD. With weight loss,EXERCIZE, and diet with low sodium some folks stabilize and can be off medicines. You have to measure it! No way to tell by looking at you, or feeling fine etc! Hypertension and renal disease are common together!