Swollen ankles, back pain, knee pain & foot pain. are they side effects of felodipine ? if so are they serious or harmless ?

Edema is a known: Side effect of felodipine...It is reversible with discontinuation of the drug and not likely to be serious. Of course stopping the drug will increase BP so talk to your physician about suitable replacement to see if swelling is due to drug.

Not necessarily : Felodipine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: headache flushing (feeling of warmth) dizziness or lightheadedness weakness fast heartbeat heartburn constipation enlargement of gum tissue around teeth if you experience any of the following symptoms, call your doctor immediately: swelling of the face, eyes, lips difficulty breathing rash.

Vessicular Tinea: I would see a doctor or podiatrist for examination of the blisters. It could be a "severe" type of fungal infection called vessicular tinea. Culture of the blisters will indicate what they are. Also the color and clarity of the fluid is important. Topical antifungal meds could help but do see a doctor first.

Felodipine can cause: Swelling of your ankles. But the confluence of back, knee, and foot pain suggest a type of spondyloarthritis. See your arthritis specialist!