Isolated systolic hypertension is common among elderly people.
Diuretics and dihydropyridine CCB like amlodepine,ARB like telmisaran,ACEI inhibitors are the suitable drugs in treatment of isolated systolic hypertension.
As in your case , amlodepine is causing ankle edema and diuretic causing hyponatremia,either you can increase the dose of telmisaran or instead of amlodepine newer 3rd generation CCB like lacidepine ,lercanidepine could be added,which are less likely to cause peripheral edema.
If there are no contraindications ,beta blockers could be added to telmisaran ,if there's a history of coronary artery disease ,heart failure etc.But beta blockers are not the first line of treatment for isolated systolic hypertension
Next Steps
any alterations in the treatment should be under the supervision of your treating doctor