If you accidentally took 2 hydroxychloroquine (Plaquenil), call Poison Control now at 1-800-222-1222 (1-844-764-7669 in Canada), even if you feel fine. The FDA label says overdose symptoms start within 1 to 3 hours, and emergency doctors say there's no established toxic dose for adults. Call 911 for fainting, seizures or trouble breathing.
Two tablets are not a handful. If your tablets are 200 mg, two add up to 400 mg, a regular daily dose on the label for lupus and rheumatoid arthritis. But the same label says "the recommended dose should not be exceeded," because the drug's effect on heart rhythm can grow as blood levels rise. The call is free and confidential, according to Poison Control.
This article provides general information about medication management and is not a substitute for professional medical advice. Consult your doctor or pharmacist for advice specific to your medications.
What to Do If You Accidentally Took 2 Hydroxychloroquine
- Call Poison Control at 1-800-222-1222. MedlinePlus gives this number to call "right away" for a suspected poisoning, and poisonhelp.org has an online tool. The UK's NHS agrees: get help if "you or a child have taken more than the prescribed dose of hydroxychloroquine." In Canada, call 1-844-764-7669, or 1-800-463-5060 in Quebec (Health Canada).
- Hold the bottle while you talk. Read off the tablet strength, how many you took, what time, and your usual daily dose.
- Mention your heart and your other medicines. The label warns against using it if you have a long QT interval (a heart rhythm pattern on an ECG) or risk factors for one. Those include heart failure, a past heart attack, a heart rate under 50, low potassium or magnesium, and other medicines that lengthen the QT interval. It can also cause severe low blood sugar and boost the effect of diabetes medicines.
- Do not make yourself throw up. America's Poison Centers put it plainly: "Do not try home remedies or try to make someone throw up."
- Do not drive yourself if you are told to go in. The NHS says to ask someone to drive you or call an ambulance.
- Call 911 instead if the person has collapsed, had a seizure, has trouble breathing or can't be woken up (MedlinePlus).
Check which number you dial. The overdose section of the Plaquenil label, and of many generic hydroxychloroquine labels, prints a poison center phone number that does not match the national Poison Help line. Use 1-800-222-1222, the number listed by MedlinePlus and America's Poison Centers.
For how this compares with other drugs, see our guide to taking medication twice by mistake.
Maximum Daily Dose of Hydroxychloroquine on the Label
"Two tablets" is not one fixed amount. Generic hydroxychloroquine comes in 100, 200, 300 and 400 mg tablets, Plaquenil in 200 mg and Sovuna in 200 and 300 mg, so check your bottle.
The Plaquenil label lists 200 mg once a day, or 400 mg once a day or split in two, as the ongoing daily dose for lupus and rheumatoid arthritis (RA). For RA, it lists a starting dose of 400 to 600 mg a day.
| Your tablet | Two tablets | Compared with label daily doses for lupus and RA | What to do |
|---|---|---|---|
| 100 mg | 200 mg | Same as the lowest ongoing daily dose | Call Poison Control |
| 200 mg | 400 mg | Same as the highest ongoing daily dose | Call Poison Control |
| 300 mg | 600 mg | Above the ongoing daily dose; top of the RA starting range | Call Poison Control |
| 400 mg | 800 mg | Above any lupus or RA daily dose on the label | Call Poison Control |
These are the two tablets alone, so tell Poison Control your whole day's total. The table covers daily lupus and RA doses, not the once-a-week schedule used to prevent malaria.
The last column never changes. The math shows where you stand, not whether you are fine. The label's eye warning is about long-term use. Daily doses above 5 mg per kg of actual body weight raise the rate of retinopathy (damage to the back of the eye). The risk also grows with the total amount taken and with more than five years of use. What one extra dose means for you is for Poison Control or your pharmacist to say.
What Happens If You Take Too Much Hydroxychloroquine (Plaquenil)?
The label's overdose section says symptoms start within 1 to 3 hours. It lists heart rhythm problems up to cardiac arrest and death, very low blood pressure, very low potassium, seizures, vision problems including temporary blindness, and coma.
It can move fast. In a 2001 case from the California Poison Control System, a 16-year-old swallowed "a handful" of 200 mg tablets. She arrived 30 minutes later with very low blood pressure, heart conduction changes and low potassium. The authors wrote that these "can occur within 30 minutes of ingestion." That was a handful, not two tablets, but it is why you call now instead of waiting to see how you feel.
For scale, a 2017 case report describes a woman whose pill box fell into her drink. About 3 g dissolved, roughly 15 tablets' worth at 200 mg each. She had ringing in her ears and facial numbness that day, and the authors describe balance and nerve problems that had barely improved 12 weeks later. Two tablets are far less.
Far less is still not a number anyone can call safe. A 2020 review for emergency doctors says that, unlike its cousin chloroquine, hydroxychloroquine has "no established lethal or toxic dose" in adults. Care is based on the symptoms a person actually has.
Hydroxychloroquine Overdose Symptoms to Watch For
Feeling normal right after the mistake settles nothing. Call either way, and use this table while you wait.
| What you notice | What to do |
|---|---|
| Fainting, collapse, or can't be woken up | Call 911 |
| A seizure | Call 911 |
| Trouble breathing | Call 911 |
| Fast or irregular heartbeat, lightheadedness or dizziness | Get emergency care now |
| Sudden vision changes or loss of vision | Get emergency care now |
| Sweating, weakness, tiredness or confusion (signs of low blood sugar) | Check your blood sugar if you can and get medical help |
| No symptoms | Call Poison Control: 1-800-222-1222 (US) or 1-844-764-7669 (Canada) |
Table sources: the MedlinePlus overdose list and the FDA label.
Hydroxychloroquine Overdose Side Effects vs Everyday Side Effects
Not every symptom after an extra tablet comes from the extra tablet. The NHS lists common side effects at regular doses, including stomach ache, nausea, diarrhea and headache. It also says the drug can blur your vision when you first start it. If that happens, do not drive, ride a bike or use machinery until your vision is back to normal. So an upset stomach alone proves nothing either way.
Heart signs are different. The label tells everyone on hydroxychloroquine to get medical help right away for a fast or irregular heartbeat, lightheadedness, dizziness or fainting, even on their usual dose. It also says low blood sugar can happen whether or not you take diabetes medicine.
Also ask whether the extra pill was really hydroxychloroquine. Plaquenil tablets are printed with "PLAQUENIL" on one side and generics carry their own codes, so read the imprint to the pharmacist. The label says steroids and other arthritis medicines may be used along with it, and those have their own rules. See what to do after a double dose of prednisone or after taking methotrexate two days in a row.
Can You Take 2 Plaquenil at the Same Time?
Only if your prescription tells you to take two tablets at once. The Plaquenil label lists 400 mg a day for lupus and RA as either one dose or two divided doses, so your prescription decides which one is yours. Don't switch from twice a day to once a day on your own.
If you take 200 mg twice a day and swallowed both tablets together by mistake, your total for the day has not changed yet. Before your next scheduled dose, call your pharmacist or Poison Control and say exactly what happened: "I take 200 mg twice a day, and I took both this morning." They will tell you what to do about the evening dose. If you're unsure what "twice a day" should look like, see what twice a day really means on your label.
How Pillo Helps
A double dose can start with one question: did I already take it? Pillo's persistent alarm won't stop until you respond, and once you mark a dose as taken, the answer sits in your dose history instead of your memory. On a twice-a-day schedule, each dose gets its own reminder, and dose spacing alerts flag doses scheduled too close together.
The label says to take hydroxychloroquine with food or milk, and Pillo's meal status checker checks a dose against whether you have eaten. Consistency is worth tracking. In a 2024 study of 181 people with lupus, blood levels in the target range were linked to 66% lower rates of lupus-related emergency and hospital care. A pill box can't tell you whether today's slot was already emptied, which is why a pill organizer alone won't stop missed doses.
Frequently Asked Questions
What if I accidentally took two doses of hydroxychloroquine?
Call Poison Control right away at 1-800-222-1222 (1-844-764-7669 in Canada), even if you feel fine. The FDA label says overdose symptoms start within 1 to 3 hours, and emergency doctors note there is no established toxic dose of hydroxychloroquine for adults. Have the bottle ready, and call 911 for fainting, a seizure, trouble breathing or someone who can't be woken.
What if a child swallowed a hydroxychloroquine tablet?
Treat it as urgent even if the child seems fine: call Poison Control at 1-800-222-1222 (1-844-764-7669 in Canada) right away, and call 911 for a seizure, trouble breathing or a child who is hard to wake. A 2005 review of US poison center data found very limited evidence on hydroxychloroquine in children under 6 and no reports of toxicity from 1 or 2 tablets, but said to treat even small doses as potentially toxic. One or two tablets of the related drug chloroquine have seriously harmed toddlers. MedlinePlus notes that many medicine containers are not child-resistant.
I can't remember if I took my Plaquenil. Should I take another?
The NHS and MedlinePlus both say not to take two doses to make up for a missed one. If you truly can't tell, call your pharmacist before taking another tablet, or see our guide on what to do when you can't remember taking your medication.
Should I skip my next dose after taking an extra hydroxychloroquine?
Don't decide on your own. The Plaquenil label has no missed-dose instructions and does not say when to take your next dose after an extra one. Tell Poison Control or your pharmacist when your next dose is due, and they will tell you whether to take it on schedule.
How long does hydroxychloroquine stay in your system?
A long time. The FDA label puts its terminal half-life at 40 to 50 days in whole blood.
This article is for informational purposes only and does not constitute medical advice. If you think you or someone else took too much hydroxychloroquine, call Poison Control at 1-800-222-1222 (1-844-764-7669 in Canada), or 911 in an emergency.
Sources
- Plaquenil (hydroxychloroquine sulfate) prescribing information, DailyMed
- Hydroxychloroquine sulfate tablets 100/200/300/400 mg prescribing information, DailyMed
- Sovuna (hydroxychloroquine sulfate) prescribing information, DailyMed
- Poisoning, MedlinePlus
- Hydroxychloroquine drug information, MedlinePlus
- America's Poison Centers, poisonhelp.org
- Poison Control, National Capital Poison Center
- Canada launches new toll-free 1-844 POISON-X number for poison centres, Health Canada
- Hydroxychloroquine, NHS
- Marquardt K, Albertson TE. Treatment of hydroxychloroquine overdose. Am J Emerg Med. 2001
- Smith ER, Klein-Schwartz W. Are 1-2 dangerous? Chloroquine and hydroxychloroquine exposure in toddlers. J Emerg Med. 2005
- Della Porta A, et al. Acute chloroquine and hydroxychloroquine toxicity: a review for emergency clinicians. Am J Emerg Med. 2020
- Chansky PB, Werth VP. Accidental hydroxychloroquine overdose resulting in neurotoxic vestibulopathy. BMJ Case Rep. 2017
- Garg S, et al. Therapeutic hydroxychloroquine blood levels are associated with fewer hospitalizations in lupus. Arthritis Care Res. 2024
