Question

Provided below is some information on the tissue distribution profile of several antibiotics: Amikacin (Aminoglycoside class) o Doesn't cross the blood-brain barrier Penetrates poorly into lungs Azithromycin (Macrolide class) Doesn't cross the blood-brain barrier 4. O O Doxycycline (Tetracycline class) o Mostly eliminated in feces, doesn't penetrate urinary tract Crosses blood-brain barrier poorly O For the types of infection listed below, indicate which of the above antibiotics should probably NOT be used in treatment Meningitis Urinary Tract Infection Pneumonia

Answer 1

• MENINGITIS : meningitis is the inflammation of brain meninges due to infection from microorganisms such as bacteria, viruses, fungi and parasites, certain drugs. The symptoms include fever, vomiting, headache, neck stiffness. The antibiotic prescribed for meningitis needs to cross the blood brain barrier and attack the underlying pathogens in the brain to treat the disease. Drugs that cannot cross or poorly cross blood brain barrier will not be able to treat meningitis. As amikacin and azythromycin cannot cross the blood brain barrier and doxycycline poorly crosses the blood brain barrier therefore they cannot exert their effect on the brain tissue. So they should not be used in meningitis.
• Urinary tract infections : Urinary tract infections are the infection of upper and lower urinary tract that includes kidneys, ureter, urinary bladder and urethra. The common symptoms are fever, frequent urination, burning and painful micturition, back pain. The antibiotics prescribed in UTI needs to exert their effect on the urinary tract to treat the infection. If an antibiotic doesn’t penetrate urinary tract it cannot cure the urinary tract infection. As azythromycin is cannot penetrate urinary tract it cannot treat UTI and thus should not be given.
• Pneumonia : pneumonia is the inflammation of they lung tissue mainly involving the smaller airway. It is caused due to infectious agents such as viruses and bacteria or certain other pathology. Common symptoms are cough, fever, chest pain, dyspnea. The antibiotic prescribed for pneumonia needs to penetrate the lung tissue to treat the disease. As amikacin poorly penetrates lung it will not be able to treat pneumonia and thus should not be prescribed for pneumonia