From the Guidelines
Opioids are the primary drugs that cause pinpoint pupils, also known as miosis, due to their activation of the parasympathetic nervous system or direct stimulation of the oculomotor nerve, as supported by recent guidelines 1. The list of opioids that can cause pinpoint pupils includes prescription medications like morphine, oxycodone, hydrocodone, codeine, fentanyl, and methadone, as well as illicit drugs like heroin. Some key points to consider:
- Other medications that can cause constricted pupils include certain antipsychotics (like haloperidol), cholinergic drugs (such as pilocarpine eye drops), and some insecticides containing organophosphates.
- The degree of pupil constriction often correlates with the dose of the drug, with higher doses typically causing more pronounced miosis, as noted in the context of opioid overdose 2.
- In opioid overdose cases, pinpoint pupils are a classic sign that healthcare providers look for, along with respiratory depression and decreased consciousness.
- Naloxone, which reverses opioid effects, will also reverse the miosis if the constriction is opioid-induced, highlighting the importance of naloxone administration in suspected opioid overdose cases 1.
From the FDA Drug Label
CNS – Euphoria, dysphoria, weakness, headache, agitation, tremor, uncoordinated muscle movements, visual disturbances, transient hallucinations, disorientation, delirium, somnolence, drowsiness, miosis, pinpoint pupils, coma, insomnia, impairment of mental and physical performance, mental clouding, lethargy, anxiety, fear, psychic dependence, mood changes, confusion. The drug that can cause pinpoint pupils is morphine 3.
From the Research
Drugs Causing Pinpoint Pupils
- Opioids, including:
Mechanism of Action
- Opioids cause dose-related decreases in pupillary size and in the velocity of constriction to a light stimulus 4
- Opioids also decrease the velocity of redilation after a light stimulus 4