When a person ingests illicit or prescription drugs, they may experience a range of behavioral, mental, and physical side effects.
One of the most visible signs that a person may be abusing certain drugs is a change in their pupil size. Several drugs cause pupils to pinpoint, or constrict, a condition known in clinical terms as eye miosis.
If you suspect that a loved one may be using drugs, it can be helpful to know some of the physical signs of drug use, and which drugs cause pupil constriction.
Which Drugs Make Eyes Pinpoint?
There are several drugs, both illicit and prescription, that may cause pupils to pinpoint.
Narcotics such as prescription opioids are commonly given to people to relieve chronic pain from illnesses or injuries. Opioids are also highly addictive, and account for approximately 50 overdose deaths every day.
Commonly abused prescription opiates include:
Small pupils may be a sign of misusing prescription opioids, which may require addiction treatment services.
Heroin is a powerful opioid drug that, when used, will cause feelings of intense euphoria. Heroin is often sold on the street in powder form or in a tar-like substance called black tar heroin.
When someone uses heroin, they may have drooping eyelids and their pupils will constrict due to the way heroin use affects the way the eye reacts to light.
Other signs of heroin use may include slurred speech, sleepiness, mood swings, sensitivity to pain, and “track marks” on the arms from needle injection.
Long-term heroin use may lead to addiction and other potentially life-threatening side effects and withdrawal symptoms.
What Causes Pinpoint Pupils?
The primary cause of constricted pupils is light. Pupils will change size depending on how much light is entering the eyes.
In bright light environments, pupils will become smaller so the eye does not get exposed to too much light. In darkened environments, pupils will enlarge (dilate) to let more light into the eyes.
Another reason pupils may constrict is from the body’s parasympathetic and sympathetic nervous system. This is also known as the fight or flight response.
If the central nervous system is stimulated from a potential threat, the parasympathetic system may cause the pupils to shrink in size.
Other Reasons People May Have Pinpoint Pupils
While opioid use is an indicator for pinpoint pupils, there are several other reasons that pupils may constrict due to injury or the use of other prescription medications.
Drug overdose occurs when somebody takes too much of a substance over a short period of time. One of the common symptoms of overdose is changes in pupil size, accompanied with other reactions such as vomiting, seizures, or confusion.
Substances that may cause overdose include opioids, methamphetamine, benzodiazepines, mescaline, Ketamine, PCP, and other stimulants or amphetamines.
Blood Pressure Medications
Certain blood pressure medications used to treat hypertension (high blood pressure) are known to cause pinpoint pupils. These drugs are given by prescription and are non-addictive.
Head Or Brain Injury
When someone injures their head or suffers a concussion, their pupils may constrict due to the parasympathetic response to the injury or other complications.
Other Illicit Drugs
While reactions will differ between people, other drugs that may cause pupil constriction and abnormal eye movements include Clonidine, inhalants, and hallucinogens such as psilocybin, LSD, MDMA, and more.
Treatment Options For Substance Use Disorders
If you or someone you care about is using drugs or alcohol, help is available in a substance abuse treatment program near you.
Drug addiction treatment services may include:
- medically monitored detox
- medication-assisted treatment (MAT)
- inpatient treatment
- outpatient treatment
- dual diagnosis treatment for co-occurring mental health disorders
- group therapy
- cognitive behavioral therapy (CBT)
Seeking an evidence-based treatment program for addiction will help you avoid potentially life-threatening withdrawal symptoms and put you on the path to sobriety.
Find Substance Abuse Treatment Today
For additional information about opioid use disorder (OUD) or other questions regarding alcohol or drug abuse, call our helpline today. Our team can assist you in finding a treatment provider.
Addiction Resource aims to provide only the most current, accurate information in regards to addiction and addiction treatment, which means we only reference the most credible sources available.
These include peer-reviewed journals, government entities and academic institutions, and leaders in addiction healthcare and advocacy. Learn more about how we safeguard our content by viewing our editorial policy.
- National Institute on Drug Abuse (NIDA) — Opioids
- National Institutes of Health (NIH) — Opioid Addiction
- National Library of Medicine — The pupillary effects of intravenous morphine, codeine, and tramadol in volunteers