Taking painkillers for a headache: what to watch for, what to do about a sudden severe headache, and who to see first if you are unsure which specialty
Take painkillers as the label or a doctor or pharmacist directs, do not exceed the recommended dose, do not drink alcohol while taking them, and tell a doctor if a painkiller does not work or the pain persists (Department of Health Drug Office, ‘Oral Analgesics’, August 2025). Sudden severe headache is one of the possible symptoms of stroke, and anyone with stroke symptoms should be taken to hospital as soon as possible (Centre for Health Protection, ‘Cerebrovascular Disease’, March 2026).
What should I watch for when taking painkillers for a headache?
Oral painkillers are most commonly used to relieve pain such as headache, period pain, toothache, back pain and arthritis, and fall into two groups, non-opioids and opioids, with non-opioids including paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) (Department of Health Drug Office ‘Oral Analgesics’ information, August 2025). The same information's reminders on taking them are in the table below.
Paracetamol (acetaminophen) is an over-the-counter medicine, an overdose can damage the liver, no more than 4 g should be taken a day, and people who are underweight or malnourished should ask a doctor before taking it; most non-steroidal anti-inflammatory drugs are prescription medicines and can cause stomach upset, stomach ulcers and gastrointestinal bleeding, are best taken with food or milk, and anyone whose stools look abnormal or black should stop the medicine immediately and seek medical help (Department of Health Drug Office ‘Oral Analgesics’ information, August 2025).
Which medicine to use, and how much, is decided by a doctor or pharmacist according to the individual case.
| Situation | The Drug Office's reminder |
|---|---|
| Dose | Take as the medicine label or a doctor or pharmacist directs, and do not exceed the recommended dose, as this increases the risk of serious side effects |
| Alcohol | Do not drink alcohol while taking painkillers, to avoid increasing the risk and severity of side effects |
| Giving the medicine to others | Do not give your painkillers to anyone else, because the causes and severity of pain differ from person to person |
| The painkiller does not work or the pain persists | Tell a doctor, because this may be related to certain diseases |
| Suspected side effects, pregnancy or breastfeeding | If you suspect a side effect, ask a doctor as early as possible; tell the doctor if you are pregnant or breastfeeding, because some painkillers should be avoided during these periods |
| Taking other medicines | Tell the doctor which medicines you are taking and your medical history, because other medicines may interact with painkillers |
What should I do about a sudden severe headache?
Sudden severe headache is one of the possible symptoms of cerebrovascular disease (stroke); other symptoms include paralysis or numbness of the body and limbs, slurred speech, blurred vision, incontinence, unsteadiness on standing or unexplained falls; anyone with these symptoms should be taken to hospital as soon as possible, because delayed treatment can affect the condition and reduce the chance of recovery (Centre for Health Protection ‘Cerebrovascular Disease’ information, March 2026).
Sudden severe headache with no known cause is also one of the warning signs of stroke and mini-stroke (Centre for Health Protection, Non-Communicable Diseases Watch, October 2013).
For other stroke symptoms, see What are the warning signs of stroke?; for Accident and Emergency triage and fees, see Accident and Emergency fees and triage; whether it is a stroke or another disease is diagnosed by a doctor.
Not sure which specialty to see for a headache: who can I see first?
Primary healthcare is the first point of contact for individuals and families in a continuing healthcare process, and family doctors are the main providers of primary healthcare (Health Bureau Primary Healthcare Blueprint, December 2022); Family Medicine provides comprehensive and continuing primary care for patients, and coordinates patients' referrals to and follow-up by other specialties and allied health services (Hong Kong Academy of Medicine, Specialty Descriptions, April 2025).
Neurology deals with diseases of the brain, spinal cord, peripheral nerves and muscles (Hong Kong Academy of Medicine, Specialty Descriptions, April 2025); which specialty a patient needs to be referred to is decided by the treating doctor according to the condition.
For choosing a family doctor, see How to choose a family doctor; for public Family Medicine Clinics, see Booking a general outpatient clinic; for general arrangements for seeking care, see Not sure which specialty to see?.
Frequently asked questions
What should I watch for when taking painkillers for a headache?
Take painkillers as the label or a doctor or pharmacist directs, do not exceed the recommended dose, and do not drink alcohol while taking them; if a painkiller does not work or the pain persists, tell a doctor (Department of Health Drug Office ‘Oral Analgesics’ information, August 2025).
What is the maximum amount of paracetamol a day?
No more than 4 g of paracetamol should be taken a day, and an overdose can damage the liver; people with impaired kidney or liver function, alcohol dependence, chronic malnutrition or dehydration should use it with caution, and people who are underweight or malnourished should ask a doctor before taking it (Department of Health Drug Office ‘Oral Analgesics’ information, August 2025). The actual dose follows the medicine label or a doctor's or pharmacist's directions.
Is a sudden severe headache a stroke?
Sudden severe headache is one of the possible symptoms of stroke, and anyone with these symptoms should be taken to hospital as soon as possible (Centre for Health Protection ‘Cerebrovascular Disease’ information, March 2026); whether it is a stroke is diagnosed by a doctor.
Which specialty should I see for a headache?
Family doctors are the main providers of primary healthcare, and primary healthcare is the first point of contact when seeking care (Health Bureau Primary Healthcare Blueprint, December 2022); which specialty a patient needs to be referred to is decided by the treating doctor according to the condition. In an emergency, go to Accident and Emergency.
What is 頭痛 in English?
Headache; see Headache: the English term.