Hi, Z pak contains azithromycin which is used to treat variety of infection like Otitis media ,sinusitis ,upper respiratory infection and many. All these complaints you have mentioned goes with side effects of azithromycin Serious side effect of azithromycin are 1)diarrhea that is watery or bloody; 2)chest pain, uneven heartbeats; 3)nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or 4)severe skin reaction -- fever, sore throat, swelling in your face or tongue, 5)burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling. Less serious side effects may include: 6)mild nausea, vomiting, diarrhea, constipation; 7)stomach pain or upset; 8)dizziness, tired feeling, or headache; 9)nervous feeling, sleep problems (insomnia); 10)vaginal itching or discharge; 11)mild itching or skin rash; 12)ringing in your ears, problems with hearing; or 13)decreased sense of taste or smell. Hence you have most of them you should immediately consult your family physician for clinical examination , and discontinue azithromycin. Thers is no antidote for it You will be symptomatically better by few days,once drug is eliminated .Its half life is 60 hours (2 and1/2 days) Drink plenty of fluids ,require short course of anti vertigo medicine with methycobal supplements for treatment of tinnitis and dizziness Hope this will help you Regards Dr Sandhya Manorenj Neurologist Hi Tech city Hyderabad