In about half the patients who have an open chest surgery there is persistent severe pain in the chest. The investigators are examining whether minocycline, a commonly used antibiotic, will prevent pain. Minocycline blocks the activity of immune cells which the investigators believe are responsible for prolonging the pain.

The study is of double-blind placebo controlled parallel groups design in up to 116 patients undergoing elective open thoracotomy. Minocycline 200mg twice daily or matching placebo are given three days before surgery.

Inclusion Criteria:

• Male or female
• Aged 18 years or older
• Undertaking elective, open thoracotomy with ample time pre-operatively to provide informed consent and undertake dosing
• Sufficient fluency in English language to read and understand consent form, fulfil study requirements and communicate with research staff
• Negative pregnancy test at screening for women of child bearing potential
• Females of child bearing potential must agree to use a medically acceptable method of contraception other than oral contraceptives from time of first dosing until one week post-operatively. Acceptable methods include abstinence, contraceptive patches, NuvaRing (etonogestrel/ethinyl oestradiol vaginal ring), diaphragm with vaginal spermicide, intrauterine device, condom and vaginal spermicide, progestin implant or injection
• Avoid prolonged, direct sunlight or ultra-violet light exposure during dosing period
• Refrain from strenuous activities and avoid changes to regular exercise patterns throughout trial period

Exclusion Criteria:

• Pregnant or breast feeding
• Known allergy to minocycline and other tetracycline antibiotics
• Pre-existing neuralgic pain condition in area designated for operation
• Physical abnormality in area designated for operation
• Taking disallowed concomitant medication
• Renal insufficiency as determined by a calculated creatinine clearance of < 60mL/min
• Hepatic dysfunction as determined by alanine transaminase and/or aspartate transaminase in excess of three times upper normal limits
• Diagnosis of systemic lupus erythematosus
• Recent diagnosis of enterocolitis or colitis
• Participation in another trial of an investigational product within 30 days of commencing dosing or are scheduled to commence trial of an investigational product during study period
• Patients who, in an Investigator's opinion, should not participate in the trial or may not be capable of following the trial schedule for any reason
• History of major psychiatric disorder not medically controlled