Hi Srinath, Thanks for asking. Zeptol is carbamazepine an excellent medicine for reducing seizures. The medicine can cause headaches and reduction in concentration as a general side effect. Or it could rarely occur as a side effect termed SIADH which causes a fall in the concentration of sodium level sin the body. But this is a very rare side effect. Still you can consider checking your blood sodium levels. The only way to confirm that zeptol is the root cause for these symptoms is to taper the dose of medication and see if the symptoms of headache and poor concentration reduce. But this should only be done under the supervision of your doctor and you may also have to add another medicine (anti-epileptic) along with zeptol mostly. Please discuss this with your physician. As of now you can take an analgesic like paracetamol for a few days to relieve the headache until you meet the physician. Hope this helps.