Benzodiazepine Side Effects

When used as prescribed, benzodiazepines can cause minor side effects, such as drowsiness and impaired muscle coordination. When they’re used in high doses or taken with other drugs, benzos can cause severe side effects.
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Sleepiness is the most common side effect of benzodiazepines, also called benzos. The prescription drugs are central nervous system depressants, meaning they slow brain activity. This relieves anxiety, muscle spasms, seizures and other health conditions.

Common benzodiazepines include Valium (diazepam), Xanax (alprazolam) and Klonopin (clonazepam).

Your first dose of a benzodiazepine puts you at increased risk of getting into accidents. You shouldn’t drive a car or operate machinery while taking a benzo until you know how your body will react to the drug.

The body eventually adapts to benzodiazepines. If you take them for multiple days, side effects should subside, and the drugs will continue to be effective for a short period of time.

Benzos aren’t recommended for long-term use because they become less effective over time. As the body continues to adapt to the presence of the benzo, it requires higher doses to feel a therapeutic effect. This is called tolerance.

People who take benzos without a prescription or use the drugs to get high can experience severe side effects. An excessive dose can make you lose coordination and pass out. Mixing the prescription drugs with other substances is especially dangerous. Combing benzos with other depressants can cause life-threatening side effects.

Short-Term Side Effects

The amount of time it takes to feel the initial effects of benzodiazepines varies. Some benzos, such as Valium and Prosom (estazolam), are fast-acting. Xanax and Ativan (lorazepam) are intermediate-acting. Klonopin is slow-acting.

Most people feel side effects of fast-acting benzos between 30 and 60 minutes after taking the drugs. Misusing the drugs by snorting them can decrease the length of time it takes to feel desired effects and side effects.

When they’re taken as prescribed, common side effects of benzos are generally mild.

Common short-term side effects of benzos include:

  • Appetite loss
  • Coordination loss
  • Drowsiness
  • Dry mouth
  • Impaired memory
  • Nausea
  • Relaxation
  • Slowed breathing
  • Slowed motor function
  • Vision problems

These side effects usually subside as the body adapts to the benzo. If the side effects are severe or continue for multiple days, you should talk to your doctor. Short-term side effects are more severe if the benzo is taken in higher doses than prescribed.

Severe short-term side effects of benzos include:

  • Clammy skin
  • Coma
  • Dilated pupils
  • Erratic behavior
  • Memory loss
  • Mood swings
  • Slow reflexes
  • Weak pulse

Benzodiazepine overdoses aren’t deadly, but they can put you at risk for injury. Because people who overdose on benzos are physically unable to defend themselves, they are at high risk for assault and robbery. Benzos are sometimes used in drug-facilitated crimes for this reason.

Long-Term Side Effects

Benzodiazepines are rarely prescribed for long-term use because they change the way the brain functions. Over time, people who take benzodiazepines begin to rely on the drugs to feel normal. This is called dependence.

Benzodiazepine dependence is a serious long-term side effect of regular benzo use. It can cause harmful withdrawal symptoms when a person stops taking the drugs. Benzodiazepine withdrawal can be life-threatening if a person stops taking the drugs suddenly.

Long-term use of benzodiazepines is also associated with an increased risk of addiction. Some people can develop benzo dependence and not become addicted. But benzodiazepine addiction is one possible long-term side effect of benzo use.

Other long-term side effects of benzodiazepine use include:

  • Cognitive decline
  • Confusion
  • Impaired judgment
  • Increased risk of accidents
  • Memory problems
  • Muscle weakness
  • Slurred speech

Many side effects go away once a person has detoxed from benzos. Others, such as cognitive decline, can persist for several months, according to a 2005 review published in the Journal of Clinical Psychiatry. Cognitive abilities that can be affected by benzos include the ability to identify visual relationships between objects, the amount of time it takes to process information, and verbal learning skills.

Drug Interactions with Benzos

Several substances interact dangerously with benzodiazepines. Taking benzos with other depressants can cause fatal side effects. Overdosing on benzos alone is rarely deadly, but it only takes a small amount of a benzo to interact with another drug and cause serious health issues.

Slowed breathing is the most serious side effect caused by interactions between benzos and other drugs. Other serious side effects of drug interactions with benzos include weak pulse, low body temperature and increased risk of injury from accidents.

Alcohol, opioids and barbiturates are the most commonly used substances that interact with benzodiazepines. Opioids are powerful prescription pain relievers that include morphine, oxycodone and hydrocodone. Barbiturates are prescribed to reduce anxiety and treat seizures. These drugs include phenobarbital and primidone.

Some people intentionally mix benzos with alcohol or opioids to increase the drug’s relaxing and euphoric effects. But this also substantially increases the risk of overdose.

Misusing benzos can result in serious health problems, including addiction and overdose. If you experience severe side effects after taking benzodiazepines, contact a doctor or call 911 immediately.

Medical Disclaimer: aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Chris Elkins, MA
Senior Content Writer,
Chris Elkins worked as a journalist for three years and was published by multiple newspapers and online publications. Since 2015, he’s written about health-related topics, interviewed addiction experts and authored stories of recovery. Chris has a master’s degree in strategic communication and a graduate certificate in health communication.
Kim Borwick, MA

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