Constricted Pupils as a Symptom of Opioid Addiction

Our pupils are designed to constrict or dilate in the presence or absence of light. This movement is controlled by the brain’s parasympathetic and sympathetic nervous system. The parasympathetic nerve causes the pupils to constrict, while the sympathetic nerve cause dilation. The abuse of drugs can affect the ability of the pupils to react properly to stimuli,as the movement of the pupils become uncontrollable in a more noticeable way.This means that the pupils, and their movements, serve as a good indicator of illicit drug use. Opioids are usually the culprit when one’s pupils are constricted without the presence of an adequate light-related stimulus.

What Are Opioids?

Opioids are substances that bind to opioid receptors in the brain, and other parts of the body, to produce psychoactive and somatic effects. Opioids were once used to treat acute pain, but are now prescribed to treat any kind of pain. They can also be used as anaesthesia during surgical procedures.

This rise in opioid prescription is mirrored in the rise of addiction rates due to the increased consumption rates among people of all genders, ages, professions, and races. Continuous use of opioids results in a higher tolerance and dependence; users could also experience withdrawal if the drug is stopped abruptly.

Overdosing on opioids, or combining them with depressant drugs, can often to lead to serious health issues including lung failure, which may result in death if not treated urgently.

Examples of opioids include fentanyl, oxycodone, hydrocodone, methadone, codeine, morphine, heroin, and opium. Heroin and opium are highly addictive and both are illegal. Yet, they are usually involved in most opioid addiction cases.

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Prolonged use of these opioids could result in pinpoint pupils, a condition where one’s pupils are abnormally small (less than two millimetres in diameter) under normal light. This condition is also known as miosis, and can also be caused by prolonged use of products that contain nicotine, such as cigarettes and other tobacco-based products.

Other Symptoms of Opioid Addiction

It is important to note that miosis is a symptom of drug addiction and other conditions, not a disease on its own. Other symptoms of opioid abuse include nausea, confusion, difficulty breathing, sleepiness, and delirium.

Signs of withdrawal include headaches, tiredness, insomnia, nausea, sweating, and diarrhoea. Other symptoms of opioid addiction you should watch out for include:

  • Continuous increasing of dosage for the desired effect
  • Intense cravings for the drug
  • Financial problems due to an inability to support a drug habit
  • Filling multiple prescriptions from different sources
  • Mood swings
  • Social isolation


Treatment for opioid addiction generally involves three steps: detox, rehab, and aftercare. Detox is the process of physically withdrawing from the drug; often happens under the watchful supervision of medical staff. After detox is complete, the next step is rehab, which can last anywhere from one to three months. Most of the time in rehab will be spent undergoing therapy, attending counselling sessions, and taking part in other activities to stimulate your recovery. Rehabilitation can be both inpatient and outpatient based on the situation.

Once the rehab period is complete, most people will begin their aftercare period, including support group meetings, additional counselling sessions, and more.

Opioids, both illegal and prescription, are easy to abuse. Miosis may be easily ignored if you are an opioid user, but when other symptoms of addiction begin to show as well, you should confide in a close friend or a family member, a medical professional or counsellor. If the symptoms get out of hand, you may be harming your body more than you acknowledge.

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