Overdose: Signs, First Aid and Symptoms by Drug

What to do in a suspected overdose

1. Call 911 if the person is unresponsive, having trouble breathing, seizing or has chest pain. Otherwise call Poison Control at 1-800-222-1222 (US), open 24 hours, free and confidential.
2. Give naloxone (nasal spray) if opioids might be involved. It is safe even if they are not. Give a second dose after 2 to 3 minutes if there is no response.
3. Check breathing. If they are not breathing normally, start CPR with chest compressions and rescue breaths if trained.
4. If breathing, place them in the recovery position on their side to keep the airway clear.
5. Stay with them until help arrives. Naloxone can wear off before the opioid does.
6. Keep the containers and note what was taken, how much and when.
7. Do not make them vomit, give them coffee, put them in a cold shower, or let them "sleep it off".

Many US states have Good Samaritan laws that protect people who call for help during an overdose.

General signs of overdose

• extreme drowsiness or unresponsiveness
• slow, shallow, irregular or stopped breathing
• blue or gray lips and fingertips
• confusion, agitation or hallucinations
• seizures
• very large or very small pupils
• chest pain, racing heart or very slow heart rate
• high body temperature, heavy sweating, or cold clammy skin
• vomiting, especially while drowsy (choking risk)

Overdose symptoms by drug type

Opioids

Pinpoint pupils, extreme sleepiness, slow or stopped breathing and blue lips. Fentanyl and its analogs, often mixed into other drugs, cause most US overdose deaths. See opioid overdose.

Sedatives and alcohol

Benzodiazepines, sleep medicines and alcohol cause drowsiness, slurred speech, unsteadiness and confusion. Combined with opioids or each other, they can stop breathing. See benzodiazepine overdose.

Stimulants

Cocaine, methamphetamine and high doses of ADHD medicines cause agitation, chest pain, very fast heartbeat, high blood pressure, overheating, seizures, stroke and heart attack.

Blood pressure medicines (antihypertensive overdose)

Signs of overdose on antihypertensive medications include:

• low blood pressure: dizziness, fainting, especially on standing
• slow heart rate with beta-blockers and some calcium channel blockers
• confusion, drowsiness, cold clammy skin and reduced urine
• high blood sugar with calcium channel blockers, and low blood sugar with beta-blockers in children
• rebound high blood pressure after stopping clonidine suddenly; clonidine overdose causes drowsiness, small pupils and slow breathing, resembling opioid overdose

Beta-blocker and calcium channel blocker overdoses can be life-threatening and delayed, especially with extended-release tablets. Treatment may include IV fluids, calcium, glucagon, high-dose insulin, and pacing. See poisoning due to antihypertensives.

Seizure medicines (anticonvulsant overdose)

• unsteady walking, slurred speech and drowsiness (common to many)
• jerky eye movements (nystagmus), especially with phenytoin and carbamazepine
• heart rhythm problems with carbamazepine, phenytoin given IV, and lamotrigine
• confusion, high ammonia and liver injury with valproate
• paradoxically, seizures with large overdoses
• coma

Treatment is supportive, with activated charcoal in some cases, and specific measures such as L-carnitine for valproate or dialysis for severe cases. See poisoning due to anticonvulsants.

Antibiotics (antibiotic overdose)

Most antibiotic overdoses cause mainly nausea, vomiting, stomach pain and diarrhea, and are rarely dangerous. Exceptions:

• isoniazid (for tuberculosis): seizures, acid build-up in the blood, coma. Treated with vitamin B6 (pyridoxine)
• fluoroquinolones: confusion, seizures, heart rhythm changes
• aminoglycosides and vancomycin (hospital drugs): kidney damage and hearing loss
• some antimalarials such as chloroquine: dangerous heart rhythm problems, low potassium

Always call Poison Control for advice. See poisoning due to antimicrobial drugs.

Acetaminophen and other pain relievers

Acetaminophen overdose often causes no symptoms at first but can destroy the liver over 1 to 3 days. Early treatment with acetylcysteine prevents this. See poisoning due to analgesics.

Antidepressants and antipsychotics

Tricyclic antidepressants cause dangerous heart rhythms and seizures. SSRIs can cause serotonin syndrome, especially in combination. See antidepressant overdose.

Treatment in hospital

• monitoring of breathing, heart rhythm, blood pressure and temperature
• airway and breathing support
• blood tests including drug levels, acetaminophen and aspirin levels, electrolytes, kidney and liver function
• activated charcoal for selected recent ingestions
• antidotes: naloxone (opioids), acetylcysteine (acetaminophen), flumazenil (rarely, for benzodiazepines), glucagon and high-dose insulin (beta-blockers, calcium channel blockers), sodium bicarbonate (tricyclics), digoxin antibodies, and others
• dialysis for certain poisons such as lithium, salicylates and toxic alcohols
• psychiatric assessment after intentional overdose

Recovery and after effects

Most people recover fully with prompt treatment. Some have lasting effects, such as brain injury from lack of oxygen, kidney or liver damage, or nerve damage. In the months after an overdose or after becoming sober, people may notice:

• low appetite and weight loss
• headaches and poor sleep
• low mood, anxiety and fatigue
• numbness or reduced sensation if nerves were compressed during prolonged unconsciousness

These can reflect withdrawal effects, depression, nutritional deficiencies or physical injury from the overdose, and deserve a medical review.

Preventing overdose

• carry naloxone if you or someone you know uses opioids, and learn how to use it
• never use alone, and avoid mixing opioids with alcohol or sedatives
• use fentanyl test strips where legal
• take medicines exactly as prescribed, and check labels for duplicate ingredients
• store medicines locked away from children and teens
• dispose of unused medicines at take-back sites
• seek treatment for substance use disorders: medicines such as buprenorphine and methadone greatly reduce overdose deaths. SAMHSA's helpline is 1-800-662-4357

Frequently asked questions

What are the signs of an overdose?

Signs include extreme drowsiness or unresponsiveness, slow or stopped breathing, blue lips or fingertips, confusion, seizures, chest pain, a very fast or slow heartbeat and vomiting while drowsy. The exact signs depend on what was taken. Call 911 if you see these.

What are the symptoms of an antibiotic overdose?

Most antibiotic overdoses cause nausea, vomiting, stomach pain and diarrhea and are rarely dangerous. Some, such as isoniazid, fluoroquinolones and certain antimalarials, can cause seizures, confusion or heart rhythm problems. Call Poison Control for advice after any overdose.

What happens if you overdose on blood pressure medication?

Blood pressure falls too low, causing dizziness, fainting, confusion, cold skin and reduced urine. Beta-blockers and some calcium channel blockers also slow the heart. These overdoses can be life-threatening and may be delayed with extended-release tablets, so seek emergency care.

What are the signs of an anticonvulsant overdose?

Common signs include drowsiness, unsteady walking, slurred speech and jerky eye movements. Depending on the drug, there may be heart rhythm problems, confusion, liver injury, seizures or coma. Treatment is in hospital and depends on the specific medicine.

What should I do if someone overdoses?

Call 911, give naloxone if opioids might be involved, check breathing and start CPR if needed, put them in the recovery position if breathing, and stay with them. Bring the medicine containers. For possible overdoses without symptoms, call Poison Control at 1-800-222-1222.