Skip to main content

Lofexidine Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Sep 27, 2023.

Applies to lofexidine: oral tablet.

Serious side effects of Lofexidine

Along with its needed effects, lofexidine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking lofexidine:

More common

  • Chest pain or discomfort
  • chills
  • cold sweats
  • confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • slow or irregular heartbeat
  • unusual tiredness

Other side effects of Lofexidine

Some side effects of lofexidine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Dizziness
  • drowsiness
  • dry mouth
  • relaxed and calm feeling
  • sleepiness
  • trouble sleeping
  • unusual drowsiness

Less common

  • Continuing ringing or buzzing or other unexplained noise in the ears
  • hearing loss

Incidence not known

For Healthcare Professionals

Applies to lofexidine: oral tablet.


The more commonly reported adverse effects have included orthostatic hypotension, bradycardia, hypotension, dizziness, somnolence, sedation, and dry mouth.[Ref]


Adverse reactions are reported at mean average daily doses up to 2.88 mg/day. With a mean dose of 2.16 mg/day, insomnia, orthostatic hypotension, bradycardia, and hypotension, were reported at 51%, 29%, 24%, and 30%, respectively. Syncope was reported in 0.9% of patients receiving 2.16 mg/day (1.4% for patients receiving 2.88 mg/day and 0% for placebo).

Blood pressure (BP) elevations of 140 mmHg (systolic) or higher, and above the subject's pretreatment BP, occurred in 39.7% (n= 23/58) of patients following discontinuation of a 5-day course of 2.88 mg/day. BP peaked on the second day after discontinuation.

Since market introduction (1992 in UK), there has been 1 case of QT prolongation, bradycardia, torsades de pointes, and cardiac arrest with successful resuscitation; there have been 3 reports of clinically significant QT prolongation in patients concomitantly receiving methadone.

Cardiac electrophysiology studies with single doses of 1.44 to 1.8 mg produced maximum mean change from baseline QTcF of 14.4 and 13.6 milliseconds, respectively in healthy normal volunteers. In a phase 3 study in opioid-dependent subjects, a maximal mean prolongation of the QTcF interval of 7.3 and 9.3 milliseconds occurred at doses of 2.16 and 2.88 mg/day respectively. In patients with renal or hepatic impairment, QT prolongation was reported; it was more pronounced in subjects with severe renal or hepatic impairment.

Very common (10% or more): Orthostatic hypotension (up to 42%); bradycardia (up to 32%); hypotension (30%), hypertension with abrupt discontinuation

Uncommon (0.1% to 1%): Syncope

Postmarketing reports: QT prolongation

Nervous system

Very common (10% or more): Dizziness (up to 23%), somnolence (up to 13%), sedation (up to 13%)


Very common (10% or more): Dry mouth (up to 11%)


Uncommon (0.1% to 1%): Tinnitus


Insomnia was reported in 51% of patients receiving a mean average daily dose of 2.16 mg/day and 55% of those receiving 2.88 mg/day; however, it was also reported by 48% of those receiving placebo.

For patients stopping this drug, a higher incidence of diarrhea, insomnia, anxiety, chills, hyperhidrosis, and extremity pain occurred in drug-treated patients compared to those taking placebo.

Very common (10% or more): Insomnia (up to 55%)

Frequency not reported: Withdrawal symptoms

Frequently asked questions


1. Product Information. Lucemyra (lofexidine). US WorldMeds LLC. 2018.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.