Ultram XR Side Effects: What to Expect and When to Call Your Doctor

Ultram XR (tramadol extended-release) is generally considered one of the milder opioid pain medications — but it still carries a meaningful side effect profile that every patient should understand. Knowing what's normal, what to monitor, and what requires immediate medical attention can keep you safe and help you get the most from your treatment.

Boxed Warnings: The Most Serious Risks

Tramadol ER carries a boxed warning — the FDA's strongest safety alert — covering several critical risks:

Addiction, abuse, and misuse: Tramadol ER is an opioid and can lead to dependence. Risk is higher in people with personal or family history of substance use disorder.

Life-threatening respiratory depression: Tramadol can slow or stop breathing, especially at higher doses or when combined with other CNS depressants, benzodiazepines, or alcohol.

Neonatal opioid withdrawal syndrome: Prolonged use during pregnancy can cause withdrawal in newborns.

Risks with benzodiazepines and CNS depressants: Combining tramadol ER with benzodiazepines (Xanax, Valium, Klonopin), sleep aids, or muscle relaxants significantly increases the risk of serious respiratory depression, coma, and death.

Common Side Effects (Expected)

These side effects occur frequently and are typically manageable. They often improve after the first few weeks as your body adjusts:

Nausea — most common; taking with food may help

Constipation — typical of opioid medications; increase water, fiber, and activity

Dizziness or lightheadedness — rise slowly from sitting or lying positions

Headache

Drowsiness/somnolence — do not drive until you know how tramadol ER affects you

Dry mouth

Flushing or sweating

Vomiting

Serious Side Effects: Know These Symptoms

These side effects are less common but require prompt medical evaluation:

Seizures: Tramadol ER lowers the seizure threshold. Seizure risk is increased with doses above 300 mg/day, history of epilepsy, and with concurrent SSRIs, SNRIs, MAOIs, tricyclics, or other opioids.

Serotonin syndrome: A potentially life-threatening drug reaction. Symptoms include agitation, hallucinations, rapid heart rate, high fever, sweating, shivering, muscle stiffness, twitching, nausea, vomiting, and diarrhea. Risk is highest when tramadol is combined with SSRIs, SNRIs, MAOIs, or triptans.

Respiratory depression: Slow or shallow breathing. Symptoms: blue lips, difficulty staying awake, very slow or noisy breathing. Call 911 immediately; administer naloxone if available.

Severe hypotension: Sudden drop in blood pressure causing fainting or extreme dizziness.

Adrenal insufficiency: More likely with prolonged use (>1 month). Symptoms: nausea, vomiting, loss of appetite, fatigue, dizziness, and weakness.

Hypoglycemia (low blood sugar): Has been reported with tramadol use; most often in patients with diabetes or on diabetes medications.

Withdrawal: What Happens If You Stop Suddenly?

If you've been taking tramadol ER regularly and stop suddenly, you may experience withdrawal symptoms beginning 8–24 hours after your last dose. Symptoms include anxiety, sweating, insomnia, restlessness, nausea, tremors, diarrhea, and muscle pain. In rare cases, hallucinations may occur. Symptoms typically peak at 2–3 days and resolve within 4–10 days.

Never stop tramadol ER abruptly without guidance from your doctor. A gradual dose taper significantly reduces withdrawal severity.

When Should You Call Your Doctor?

Nausea or constipation that persists beyond 2–3 weeks despite dietary changes

Dizziness that affects your ability to function or causes falls

Feeling like the medication is no longer working (may need dose adjustment)

Any new symptoms: rash, confusion, extreme drowsiness, difficulty urinating

When to Call 911 Immediately

Seizure

Difficulty breathing or blue-tinged lips/fingernails

Unresponsiveness or extreme difficulty waking up

Rapid heart rate combined with high fever, muscle stiffness, and agitation (serotonin syndrome)

For a complete list of medications that can cause dangerous interactions with tramadol ER, see our guide: Ultram XR Drug Interactions: What to Avoid and What to Tell Your Doctor.