What Drugs Cause Pinpoint Pupils?

Different drugs of abuse can influence the body in unique ways that are useful to understand. In fact, pupil dilation is often used to help first responders and other medical professionals determine what type of drug a person may have been using, especially in cases of pinpoint pupils and opioid overdose.

Although there are several drugs that can cause pupil constriction, listed below, opioids are perhaps the most noteworthy due to the overdose risk involved.

Opioids are a class of highly addictive euphoric drugs that are responsible for the vast majority of drug overdose deaths in the U.S., according to the Centers for Disease Control and Prevention (CDC). These drugs may be used knowingly or cut into other drugs without the person’s knowledge. 

Opioid use and overdose are identifiable through a variety of telltale signs and symptoms, including constricted or pinpoint pupils. The opioid overdose antidote drug naloxone (brand name, Narcan) is available over the counter today and can be life-saving when used right away.

How Opioids Cause Pinpoint Pupils

Pupils are highly sensitive to light and are able to rapidly dilate (enlarge) or constrict (shrink) in response to the amount of light available. In dark conditions, pupils grow larger to allow more light in and increase vision. In bright conditions, they grow smaller to limit the amount of light taken in by the eye. 

This function is automatic and influenced by both the sympathetic autonomic nervous system, which handles the “flight-fight-freeze” response and arousal, and the parasympathetic autonomic nervous system, which handles bodily activity when it is time to “rest and digest.” The more active the sympathetic system becomes, the more pupils will tend to dilate, regardless of light conditions (mydriasis). Likewise, the more active the parasympathetic system becomes, the more the pupils will tend to constrict in both bright and dark conditions (miosis).

Opioids bind to specialized opioid receptors located throughout the central nervous system. These receptors usually work with endorphins, natural neurotransmitter chemicals that help regulate pain, stress, mood, and well-being. Opioid drugs, however, can activate these receptors to a far greater degree than any natural endorphin, canceling out feelings of pain and stress and producing intense euphoria at higher doses. 

Opioids also strongly stimulate the parasympathetic system, dropping blood pressure, heart rate, and breathing in the body, and causing the iris sphincter muscle to relax and the pupil to contract and shrink, producing the appearance of small or pinpoint pupils. 

Other Drugs Associated With Pupil Constriction

While pupil constriction is an important diagnostic tool for identifying opioid use and overdose, there are other substances that can also cause miosis by influencing the brain, the parasympathetic nervous system, the cranial nerve, or the iris dilator or sphincter muscles. 

These substances are known to include:

  • PCP, an illicit dissociative drug also known as angel dust
  • benzodiazepines like alprazolam, diazepam, and klonopin
  • nicotine, a legal stimulant found in tobacco products
  • pilocarpine eye drops used to treat glaucoma
  • cholinergic drugs including acetylcholine, carbachol, and methacholine
  • second-generation or atypical antipsychotics including risperidone, haloperidol, and olanzapine
  • phenothiazine antipsychotics including prochlorperazine, chlorpromazine, and fluphenazine
  • organophosphates used in insecticides, herbicides, and nerve agents
  • clonidine, used to treat high blood pressure, ADHD, withdrawal syndrome, and menopausal hot flashes

Miosis can also be caused by migraines, stroke, irritation or swelling of the eye, nerve problems, and other issues not related to specific substances. 

What Are Opioid Drugs?

Opioids are a large group of both natural and synthetic substances chemically related to morphine, a natural-occurring opiate drug extracted from the opium poppy. Opioids have been used to treat severe pain for thousands of years and are important tools in modern medicine. However they are notoriously prone to abuse and can be exceptionally habit-forming if used improperly. 

Examples of common opioids include:

  • codeine
  • morphine
  • meperidine (Demerol)
  • tramadol (Ultram)
  • oxycodone (OxyContin)
  • oxymorphone (Opana)
  • hydromorphone (Dilaudid)
  • hydrocodone (Vicodin, Norco, Lortab)
  • methadone
  • buprenorphine
  • fentanyl
  • heroin

All opioids are considered controlled substances in the United States. Those used for prescription pain relief are placed in Schedule II, with a few exceptions according to the Controlled Substance Act. Schedule II designates them as substances with valid medical uses that nevertheless carry the highest level of risk for diversion, abuse, dependence, and addiction. 

Those drugs that are considered unfit for medical use, including heroin and any number of experimental, “designer” opioid variants, are placed in Schedule I as illicit substances. Possessing or misusing either a Schedule I or II drug without a valid prescription is considered a serious crime under both federal and state laws. 

Opioid Overdose Symptoms

Opioid drugs vary dramatically in potency, with some like fentanyl being so potent that an amount equivalent to a few grains of salt can suppress an average adult’s bodily functions, including stopping their breathing. However, all opioid drugs have the capacity to trigger harmful or deadly overdose effects if taken in excessive doses. 

Signs and symptoms of an opioid overdose include:

  • sedation, limpness, and problems moving
  • slow, shallow, or irregular breathing (respiratory depression)
  • gasping or gurgling noises (“death rattle”)
  • weak or unsteady pulse
  • pinpoint pupils
  • cold and clammy skin
  • pale or blue-tinted skin, fingertips, and lips
  • becoming unresponsive or losing consciousness (coma)

Because opioid overdoses impact breathing and can deny oxygen to the brain, people who experience them can swiftly develop severe brain damage and other lasting health issues. If prompt and effective care is not provided, death may occur. 

The best way to prevent an overdose is to seek addiction treatment. However, harm reduction practices include only using opioids with other people present who can assist in an emergency or calling a volunteer-run harm reduction phone line when using, which can monitor callers’ conditions and summon emergency services to their location if needed. 

Responding To An Opioid Overdose

If you believe someone is experiencing an opioid overdose, it is extremely important that you react quickly. If the person is unresponsive, immediately call 911 for emergency medical assistance. You should also administer Narcan as quickly as possible if you have access to it. 

Narcan is an opioid antagonist that works by clearing opioid drugs from receptors in the central nervous system, swiftly reversing the drug’s effects and restoring the body’s natural internal balance. Narcan is not harmful, so administering it even if opioids aren’t involved won’t cause adverse effects.

After administering Narcan, stay with the person, place them on their side in the recovery position, and monitor their breathing and heart rate. If these stop, begin administering CPR and use an AED if one is available. First responders will take over as soon as they arrive. 

Opioid Overdose Statistics

According to the CDC, the U.S. is deep into the third and deadliest wave of the opioid overdose epidemic, which first began in the late 1990s. Since this time, opioid deaths have climbed continuously and at an increasing rate, driven first by the abuse of prescription drugs, then by a rise in heroin use in 2010, and now by the abundance and potency of illicit synthetic opioids, mostly fentanyl. 

In 2022 alone there were 107,941 reported drug overdose deaths in the U.S., or around 32.4 deaths per 100,000 Americans. Just over three-quarters of these overdose deaths involved an opioid drug (81,806 deaths), and 68.4 percent involved a non-methadone synthetic opioid like fentanyl (73,838 deaths). 

In comparison, only 5,871 deaths in 2022 were confirmed to involve the illicit drug heroin, which has increasingly been laced with or replaced by fentanyl and other higher-potency alternatives. Note that many opioid overdoses also involved the use of other drugs like alcohol, stimulants, and benzodiazepines. 

Almost one in three Americans today are reported to know someone who has died of a drug overdose, and drug overdoses have become the leading cause of accidental death in the U.S. ahead of falls and motor vehicle accidents. 

Overdose isn’t the only risk that comes with opioid abuse. Addiction, dependence, constipation, physical and mental illnesses, brain damage, vision damage, and other issues all become increasingly common the longer a person misuses these powerful substances outside of medical necessity. 

What Qualifies As An Opioid Use Disorder

Opioid misuse is defined as any use of an opioid drug that occurs outside of the medical system, i.e., used other than as prescribed by a healthcare provider to treat a medical issue. This includes any use of illicit opioids, use of opioids that have not been prescribed to you, use of opioids in any other way than as prescribed (including modification of the drugs, dose, or dosing schedule or any use of alcohol or other drugs along with opioids), or opioids prescribed under false pretenses. 

An opioid use disorder (OUD), on the other hand, describes a condition of ongoing, chronic, compulsive misuse of opioid drugs that occurs despite those drugs causing negative, harmful effects in a person’s life. OUDs usually involve both physical and psychological forms of opioid dependence, and can impact anyone under certain circumstances. 

Criteria used to diagnose an OUD include:

  • being unable to stop taking an opioid or reduce use
  • frequently using more of the drug than intended
  • spending an excess amount of time getting, taking, or recovering from opioids
  • having opioid cravings
  • falling behind in personal responsibilities due to opioid use 
  • experiencing relationship problems due to continuing opioid use
  • giving up important social, occupational, or recreational activities because of opioid use
  • using opioids in risky ways or situations
  • using opioids despite having a physical or psychological problem caused or made worse by opioid use
  • needing larger and larger doses over time due to tolerance
  • experiencing opioid withdrawal symptoms when going too long between doses

If you or someone you love meets any combination of these criteria, it’s important to talk to your healthcare provider and consider recovery treatment programs like those provided by Ohio Recovery Center.

Treatment For Opioid Abuse And Addiction

At Ohio Recovery Center, our experienced treatment center staff offer comprehensive and personalized courses of treatment for all forms of OUD. 

Our evidence-based services include:

  • medical detoxification and withdrawal symptom management
  • medication-assisted treatment (MAT) services
  • cognitive behavioral therapy (CBT) and other forms of individual and group talk therapy
  • dual diagnosis treatment programs for co-occurring mental health disorders
  • peer support groups 
  • family psychoeducation
  • alternative treatment programming
  • aftercare coordination

Our residential facility is situated on 55 acres of beautiful woodlands, offering outdoor spaces for recreation and relaxation, a fully equipped fitness center, modern residential cottages, and more.

Get Help At Ohio Recovery Center Today

To learn more about Ohio Recovery Center, our state-of-the-art treatment center, and our personalized opioid recovery treatment pathways, please connect with us today.

  1. American Journal of Pharmaceutical Education - Physiology of the Autonomic Nervous System https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1959222/#:~:text=The%20sympathetic%20system%20controls%20%E2%80%9Cfight,%E2%80%9Crest%20and%20digest%E2%80%9D%20functions.
  2. Cleveland Clinic - Eye Miosis (Constricted Pupils): Causes & Treatment https://my.clevelandclinic.org/health/symptoms/23575-eye-miosis
  3. Cleveland Clinic - Eye Mydriasis (Dilated Pupils): Causes & Treatment https://my.clevelandclinic.org/health/symptoms/22238-dilated-pupils
  4. National Institute on Drug Abuse (NIDA) - Prescription Opioids DrugFacts https://nida.nih.gov/publications/drugfacts/prescription-opioids

Written by Ohio Recovery Center Editorial Team

Published on: June 26, 2024

© 2024 Ohio Recovery Center | All Rights Reserved

* This page does not provide medical advice.

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