Brief Answer:
several possibilities can be there..

Detailed Answer:
Hello XXXXX, Welcome to HCM,
I've gone through your query and understand your concern,

First of all, let me inform you that this particular group of antibiotics (RIFAMPICIN & AZITHROMYCIN & AMIKACIN) is typically prescribed for a group of Mycobacterial infection and pneumonitis, which may or may not be associated with pulmonary fibrosis..

There are several types of pulmonary fibrosis(worst of them is the Idiopathic one), some of them itself can cause a battery of symptoms including the lower back and leg weakness..

In a rare occasion, there is reported incidence of lower back and leg weakness due to Amikacin, but since it's given as nebulizer, I wouldn't attribute it as the cause here..the other two antibiotics also have a battery of related adverse effects, however, it's actually the benefits of them which outweighs the adverse effect in the given scenario..

But the pulse rate is going high and blood pressure is going too low is definitely quite concerning, and has to be evaluated further by your doctor without any further delay..it may be due to the ongoing infection, dehydration, any underlying inflammation, fever, cardiac rhythm anomaly(secondary to infection or even drug induced)..

You need to be clinically examined and few investigations(eg. CBC, CRP, Electrolytes, Chest X-ray repeat, Blood gas analysis, KFT and 12 lead EKG along with a 2D-Echocardiography etc.) have to be done to rule out anything concerning in this regard..

Please remain well hydrated in the meanwhile, drink plenty of water (if there's no contraindication for that)..

I'd not suggest any further delay in this regard and advice an immediate reporting of this to your doctor for a thorough clinical evaluation and management accordingly..

Please let me know how you stay in the due course..

Take Care
Kind Regards

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Brief Answer:
You're always welcome to have my suggestions..

Detailed Answer:
Your most welcome Dear,

Yes, please do so..

Don't worry, with timely intervention, it'll be well manageable..

For future reference you can always get in touch with me, below is my Direct follow-up link through which you can contact me directly anytime anywhere, I'll be happy to help -

http://www.healthcaremagic.com/Funnel?page=askDoctorDirectly&docId=71041

Take Care
Kind Regards

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