Severe headache since increasing the Zoloft dosage?

It is possible for an increase in Zoloft dosage to cause a headache as a side effect. This is fairly common but usually temporary. If the headache is intolerable, you may want to consider going back to your previous dosage temporarily and then gradually increasing it later. It would be a good idea to inform your pharmacist if you decide to do this, so they can monitor your progress closely. If you have any more questions or concerns, feel free to ask for further assistance.