Xanax (alprazolam) commonly causes drowsiness, lightheadedness, and irritability. These are the side effects most people notice first, but the full picture includes cognitive changes, physical dependence, and serious risks that increase with longer use. Here’s what to expect and what to watch for.
How Xanax Works in the Brain
Xanax enhances the effect of GABA, the brain’s main calming chemical. GABA slows neuron activity, which is why the drug reduces anxiety and promotes relaxation. Xanax doesn’t activate this system directly. Instead, it makes GABA more effective at lower concentrations, essentially turning up the volume on your brain’s natural braking system. That mechanism explains most of the side effects: the same calming action that treats anxiety also causes sedation, slowed reflexes, and mental fogginess.
Common Side Effects
Most people taking Xanax experience some degree of drowsiness, especially in the first few days. Irritability is also frequently reported, which can seem counterintuitive for an anti-anxiety medication. Other common effects include difficulty concentrating, changes in appetite, and feeling lightheaded or unsteady on your feet.
These side effects tend to be more noticeable at higher doses and often improve as your body adjusts. But for some people, the sedation and cognitive dulling persist as long as they’re taking the medication.
Less Common but Serious Reactions
A smaller number of people experience effects that need immediate medical attention. These include difficulty breathing, seizures, and skin reactions like rash or hives. Breathing problems are particularly concerning because Xanax can suppress respiratory function, especially in people who already have lung conditions.
Some people also develop paradoxical reactions, meaning the drug produces the opposite of its intended effect. These can include confusion, hallucinations, unusual excitement or nervousness, worsening depression, and even suicidal thoughts. These reactions resemble the disinhibition that happens with alcohol, where someone acts in ways that are out of character. If you notice strange thoughts or behavioral changes, that’s not a normal adjustment period.
Risks of Combining With Opioids or Alcohol
Mixing Xanax with opioids or alcohol is one of the most dangerous drug combinations. All three suppress breathing and sedate the central nervous system, and the effects stack. A cohort study in North Carolina found that the overdose death rate among patients taking both opioids and benzodiazepines was 10 times higher than among those taking opioids alone. A study of U.S. veterans showed that adding a benzodiazepine to an opioid prescription increased the risk of overdose death in a dose-dependent way, meaning higher doses carried proportionally higher risk.
Both opioids and benzodiazepines now carry FDA boxed warnings about the danger of using them together. The core problem is simple: both types of drugs can suppress breathing enough to cause fatal overdose, and combining them makes that threshold much easier to reach.
Withdrawal Can Be Severe
Xanax withdrawal can begin within 24 hours of the last dose, and the timeline follows a rough pattern. Early symptoms in the first day include rebound anxiety, restlessness, and difficulty sleeping. Over days one through four, these intensify into panic attacks, sweating, tremors, and nausea. The peak withdrawal phase hits between days five and fourteen, when insomnia, confusion, and seizures are possible. Symptoms begin stabilizing around weeks two through four, though anxiety and sleep problems often linger.
Some people experience protracted withdrawal lasting three months or longer. Studies estimate that 10% to 25% of chronic benzodiazepine users develop protracted symptoms, typically new or worsening anxiety and depression. Other withdrawal symptoms can include muscle spasms, hypersensitivity to light and sound, hyperventilation, hallucinations, and a disturbing sensation of being detached from your body.
The FDA’s boxed warning for all benzodiazepines specifically highlights the risks of physical dependence and withdrawal. Stopping abruptly is dangerous. The standard approach is a gradual dose reduction, which helps prevent seizures and other severe withdrawal effects.
Long-Term Cognitive Effects
Prolonged Xanax use carries cognitive risks that go beyond everyday fogginess. Confusion, clouded thinking, and memory lapses are well-documented side effects of benzodiazepines, and these problems tend to worsen with higher doses and longer use.
More concerning is the potential link to dementia. Two large population studies found that people who used benzodiazepines for longer than a few months had an increased risk of dementia, with the risk rising alongside both dose and duration. A French-Canadian study put specific numbers on this: people who took benzodiazepines for three months or less had about the same dementia risk as non-users. Those who took them for three to six months had a 32% greater risk of developing Alzheimer’s disease. Those who used them for more than six months had an 84% greater risk. Notably, Xanax is a short-acting benzodiazepine, and the study found that long-acting versions like diazepam (Valium) carried even higher risk. But the association was present across the class.
Higher Risks for Older Adults
People over 65 face amplified side effects from Xanax. Falls are a major concern. Both long-acting and short-acting benzodiazepines increase fall risk in older adults, and tolerance to this impairment does not develop over time. Short-acting benzodiazepines like Xanax can cause severely incapacitating psychomotor effects in the first few hours after a dose, raising the risk of a fall if someone gets out of bed during the night. These falls frequently lead to hip fractures.
Driving ability is also affected. Older adults on benzodiazepines have a significantly increased risk of injurious motor vehicle accidents, particularly at higher doses. And in people with existing cognitive decline, long-term benzodiazepine use commonly worsens underlying dementia. The American Geriatrics Society lists benzodiazepines as potentially inappropriate medications for older adults for exactly these reasons.
Risks During Pregnancy
Taking Xanax during pregnancy poses risks to both mother and baby. Infants exposed to benzodiazepines before birth can experience drug withdrawal after delivery. When benzodiazepine exposure is combined with opioid exposure, the effects are worse: these infants are more than 50% more likely to need medication like morphine to manage withdrawal symptoms compared to babies exposed to opioids alone. For the mother, combining a benzodiazepine with an opioid during pregnancy increases overdose risk. Benzodiazepines are designed for short-term use, and prolonged use during pregnancy carries compounding risks for both.
Physical Dependence vs. Side Effects
One of the trickiest aspects of Xanax is that physical dependence develops relatively quickly and can be difficult to distinguish from the condition it’s treating. When the drug wears off between doses, rebound anxiety can feel identical to the original anxiety disorder, creating a cycle where the medication seems increasingly necessary. This is a pharmacological effect of the drug, not a sign that your anxiety is worsening. The FDA now requires all benzodiazepine labels to warn about the risks of abuse, misuse, addiction, physical dependence, and withdrawal, reflecting how central these concerns are to the drug’s risk profile.