Headaches that cannot wait
Thunderclap onset, worst headache of life, headache with fever and stiff neck, confusion, weakness on one side, or headache after head injury — emergency assessment, not a side-effect wait.
Tension headache versus medicine timing
Headaches that appear within hours of each dose and relieve between doses suggest timing worth discussing. Headaches unrelated to dosing schedule may have other causes — hydration, caffeine withdrawal, eye strain, stress.
Caution with pain medicine stacking
Before adding OTC pain relievers for headache, ask a pharmacist — many combination products contain sedating antihistamines or interact with your other medicines. Duplicating sedating ingredients is a common mistake.
Hydration and caffeine
Anticholinergic dry mouth sometimes reduces fluid intake; dehydration headaches are common and unrelated to mysterious toxicity. Caffeine withdrawal after cutting coffee because of anxiety also produces headaches — track both medicine and lifestyle changes.