Visual disturbance is the most likely to precede primary succession
Nitrofurantoin is an antibiotic drug that used for treating urinary tract infection. This drug is relatively safe but has toxicity to some organ such as liver, nervous and lungs.
Prior lab work will exclude the chance that the organ is damaged before treatment. It also can be used to monitor if there are major adverse effect happens to the patient.
Answer:
respiration, waste production, food intake, cells, breathing