What You Need to Know About Diazepam Side Effects

Every medication comes with potential side effects, and Diazepam (brand name Valium) is no exception. The good news is that most people tolerate Diazepam well when taken as prescribed. But knowing what to watch for—and when to get medical help—can make all the difference.

This guide covers the common and serious side effects of Diazepam, which groups are at higher risk, and practical tips for managing side effects.

What Is Diazepam?

Diazepam is a benzodiazepine, a class of medications that work by enhancing the calming effects of a brain chemical called GABA. It's prescribed for anxiety disorders, muscle spasms, seizures, and alcohol withdrawal. You can learn more in our detailed guide on how Diazepam works.

Diazepam comes in several forms: oral tablets (2 mg, 5 mg, 10 mg), oral solution, injectable solution, rectal gel (Diastat), and nasal spray (Valtoco).

Common Side Effects

These side effects are the most frequently reported and usually mild. They often improve as your body adjusts to the medication over the first week or two:

• Drowsiness and sedation — This is the most common side effect. You may feel sleepy, especially when first starting Diazepam or after a dose increase.
• Fatigue — A general feeling of tiredness that can affect your energy throughout the day.
• Muscle weakness — Ironically, while Diazepam treats muscle spasms, it can also cause a feeling of overall muscle weakness.
• Dizziness — You may feel lightheaded, especially when standing up quickly.
• Ataxia (impaired coordination) — Diazepam can affect your balance and coordination, making you feel unsteady on your feet.
• Blurred vision — Some people notice their vision isn't as sharp while taking Diazepam.
• Headache — Mild headaches can occur, particularly in the first few days.
• Dry mouth — A cottony or dry feeling in your mouth.
• Nausea — Mild stomach upset, which often improves if you take Diazepam with food.
• Constipation — Diazepam can slow down your digestive system.

Most of these side effects are dose-related, meaning they're more likely at higher doses. Your doctor will typically start you at the lowest effective dose—often 2 mg to 5 mg—to minimize these effects.

Serious Side Effects

While uncommon, some side effects require immediate medical attention. Call your doctor or go to the emergency room if you experience any of the following:

Respiratory Depression

Diazepam carries an FDA boxed warning about the risk of severe breathing problems, especially when combined with opioids (such as Oxycodone, Hydrocodone, Fentanyl, or Morphine) or alcohol. Signs include:

• Slow, shallow breathing
• Difficulty catching your breath
• Bluish tint to lips or fingertips
• Extreme sleepiness where you can't be woken

This is a medical emergency. Call 911 immediately.

Severe Sedation or Coma

Taking too much Diazepam or mixing it with other CNS depressants can lead to dangerously deep sedation. Warning signs include confusion, extreme drowsiness, slurred speech, and loss of consciousness.

Paradoxical Reactions

In rare cases, Diazepam can cause the opposite of its intended effects:

• Increased anxiety or agitation
• Aggression or hostility
• Hallucinations
• Rage or excitement

Paradoxical reactions are more common in children, elderly patients, and people with certain psychiatric conditions. If you notice these symptoms, contact your doctor right away.

Physical Dependence and Withdrawal

Diazepam can cause physical dependence, even when taken exactly as prescribed. The FDA has a boxed warning about the risks of abuse, misuse, addiction, and withdrawal. Never stop Diazepam abruptly—doing so can cause serious withdrawal symptoms including:

• Seizures
• Tremors
• Severe anxiety
• Insomnia
• Sweating
• Muscle cramps

Always work with your doctor to gradually taper your dose if you need to stop taking Diazepam.

Suicidal Thoughts

Rarely, Diazepam may worsen depression or trigger suicidal ideation. If you or a loved one experience new or worsening depression, thoughts of self-harm, or unusual changes in behavior, seek help immediately. Call the 988 Suicide and Crisis Lifeline (call or text 988) for immediate support.

Severe Allergic Reactions

Anaphylaxis is rare but possible. Seek emergency help if you develop hives, swelling of the face or throat, or difficulty breathing after taking Diazepam.

Side Effects in Specific Populations

Elderly Patients

Older adults are more sensitive to Diazepam's effects. They're at higher risk for:

• Excessive sedation
• Falls and fractures (due to dizziness and impaired coordination)
• Confusion and memory problems
• Longer duration of effects (Diazepam's half-life can be much longer in elderly patients)

Doctors typically prescribe lower doses for elderly patients—often starting at 2 mg to 2.5 mg once or twice daily.

Pregnant and Breastfeeding Women

Diazepam is classified as Pregnancy Category D, meaning there is evidence of risk to the developing baby. Risks include:

• Possible congenital malformations (especially in the first trimester)
• Neonatal withdrawal syndrome if taken late in pregnancy
• Floppy infant syndrome (decreased muscle tone, breathing difficulties)

Diazepam passes into breast milk and is not recommended during breastfeeding.

People with Liver Problems

Diazepam is extensively processed by the liver (through enzymes CYP2C19 and CYP3A4). If your liver isn't working well, Diazepam can build up in your system and cause stronger or longer-lasting side effects. Your doctor will likely use a lower dose and monitor you more closely.

People with Respiratory Conditions

If you have COPD, sleep apnea, or other breathing problems, Diazepam should be used with extreme caution. The medication's muscle-relaxing and sedating effects can worsen respiratory function.

How to Manage Common Side Effects

Here are practical strategies for dealing with the most common Diazepam side effects:

• Drowsiness — Take Diazepam at bedtime if your dosing schedule allows. Avoid driving or operating heavy machinery until you know how the medication affects you.
• Dizziness — Stand up slowly from sitting or lying positions. Stay hydrated.
• Dry mouth — Sip water throughout the day, chew sugar-free gum, or use a saliva substitute.
• Nausea — Take Diazepam with a small meal or snack. Food may slow absorption slightly but can reduce stomach upset.
• Constipation — Increase your fiber intake, drink plenty of water, and stay physically active.
• Blurred vision — This usually improves within the first few weeks. If it persists, let your doctor know.

If any side effect is severe, persistent, or interferes with your daily life, don't just stop taking Diazepam on your own. Talk to your doctor—they can adjust your dose or suggest an alternative medication.

Important Safety Reminders

• Don't mix with alcohol — Combining Diazepam and alcohol increases the risk of life-threatening respiratory depression.
• Watch for drug interactions — Many medications can increase Diazepam's effects or cause dangerous interactions. Always tell your doctor about everything you take.
• Don't stop suddenly — Always taper Diazepam under medical supervision.
• Store safely — Keep Diazepam locked up and away from children and anyone who might misuse it.

Final Thoughts

Diazepam is an effective medication when used properly, but it's important to know what side effects to watch for. Most people experience only mild drowsiness or fatigue that improves over time. The serious side effects—especially respiratory depression and dependence—are manageable with proper medical supervision.

The key is staying in close contact with your doctor, especially when you're first starting Diazepam or adjusting your dose. If something doesn't feel right, speak up. Your doctor can help you find the right balance between managing your condition and minimizing side effects.

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