Clinical Trials and Studies

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We're sorry, but this trial is no longer enrolling volunteers.



This study will compare Z160 and placebo in patients with Postherpetic Neuralgia for safety and efficacy for a period of 6 weeks.


Phase 2 - takes the treatment one step further, assessing the activity of a particular therapy in a disease, often building upon leads from the Phase I trial. While patients are generally required to be previously untreated, participation in a Phase II trial doesn't usually preclude the patient from getting the standard treatment after they've received the investigational agent. At best they are allowed to get a new drug they wouldn't be able to get otherwise that may turn out to be better for their disease.

Inclusion and Exclusion Criteria

  • Provide written informed consent.
  • Either sex but must be aged >=18 years.
  • Diagnosis of PHN as defined by the presence of pain in the area affected by herpes zoster >=6 months after the herpes zoster skin rash has healed.
  • Pain score over the last week of >=3 and <=8 on the PI-NRS
  • If female, the subject must be postmenopausal , surgically sterilized for >=3 months before the screening visit, or agree to use 2 reliable methods of contraception if of childbearing potential. If male, the subject must agree to use condoms.
  • Willing and able to comply with all study procedures.

  • Severe pain caused by diseases other than PHN.
  • Neurolytic or neurosurgical therapy for PHN within 6 months of screening (subjects who received a spinal cord stimulator implant at least 6 months before screening are eligible, but the settings need to remain stable during the double blind study period without use of a magnet).
  • History of seizure, excluding pediatric febrile seizures, or currently has seizures.
  • Stroke or transient ischemic attack (TIA) <=6 months before the screening visit.
  • History of or a current diagnosis of schizophrenia or bipolar disorder.
  • Major depressive disorder or generalized anxiety disorder <=6 months before the screening visit. Subjects who are on stable doses of selective serotonin uptake inhibitors (SSRIs) for depression (other than major depressive disorder) are eligible for the study.
  • Clinically significant alcohol or substance dependency <=1 year before the screening visit
  • Imminent risk of suicide (positive response to question 4 or 5 on the C-SSRS) or had a suicide attempt within 6 months before the screening visit.
  • Clinically significant conditions that, in the investigator's opinion, may interfere with the study procedures or compromise the subject's safety.
  • Malignancy (other than nonmetastatic basal or squamous cell carcinoma of the skin or carcinoma in situ of other organs that was surgically removed >1 year before screening and has not recurred).
  • Condition that is known to interfere with the absorption, distribution, metabolism, or excretion of drugs.
  • Illness within 30 days before screening.
  • History of hypersensitivity to calcium channel blockers.
  • Multiple drug allergies
  • Opioids (at doses exceeding the equivalent of 15 mg of oral morphine) or a high-dose capsaicin patch (Qutenza) <=30 days before the screening visit.
  • Moderate or strong cytochrome P450 inducer within 30 days before the screening visit.
  • Digoxin or prohibited medications that cannot be discontinued before randomization.
  • Other exclusions apply.


  • California

    • Investigative Site, Los Angeles, California, 90033
    • Investigative Site, Irvine, California, 92618
    • Investigative Site, Thousand Oaks, California, 91360
    • Investigative Site, San Francisco, California, 94109
  • Arizona

    • Investigative Site, Peoria, Arizona, 85381
    • Investigative Site, Phoenix, Arizona, 85020
    • Investigative Site, Scottsdale, Arizona, 85251
    • Investigative Site, Chandler, Arizona, 85224
    • Investigative Site, Mesa, Arizona, 85213
  • Utah

    • Investigative Site, Murray, Utah, 84123
    • Investigative Site, Salt Lake City, Utah, 84106
  • New Mexico

    • Investigative Site, Albuquerque, New Mexico, 87102
  • Colorado

    • Investigative Site, Colorado Springs, Colorado, 80920
    • Investigative Site, Boulder, Colorado, 80304
    • Investigative Site, Denver, Colorado, 80218
  • Washington

    • Investigative Site, Tacoma, Washington, 98405
    • Investigative Site, Bellevue, Washington, 98007
  • Oklahoma

    • Investigative Site, Oklahoma City, Oklahoma, 73112
  • Texas

    • Investigative Site, Austin, Texas, 78731
    • Investigative Site, Richardson, Texas, 75080
  • Nebraska

    • Investigative Site, Omaha, Nebraska, 68124
  • Missouri

    • Investigative Site, Kansas City, Missouri, 64114
    • Investigative Site, St. Louis, Missouri, 63117
    • Investigative Site, Hazelwood, Missouri, 63031
  • Louisiana

    • Investigative Site, Shreveport, Louisiana, 71105
  • Arkansas

    • Investigative Site, Little Rock, Arkansas, 72205
  • Indiana

    • Investigative Site, Evansville, Indiana, 47714
  • Mississippi

    • Investigative Site, Ocean Springs, Mississippi, 39564
  • Illinois

    • Investigative Site, Chicago, Illinois, 60602
  • Tennessee

    • Investigative Site, Nashville, Tennessee, 37205
    • Investigative Site, Tullahoma, Tennessee, 37388
  • Alabama

    • Investigative Site, Birmingham, Alabama, 35216
  • Ohio

    • Investigative Site, Kettering, Ohio, 45429
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