Effect of Midazolam on White-coat Hypertensive Dental Patients

• Blood pressure [ Time Frame: Until 10 minutes after drug administration ] [ Designated as safety issue: Yes ]
• Heart rate [ Time Frame: Until 10 minutes after drug administration ] [ Designated as safety issue: Yes ]
• Oxygen saturation [ Time Frame: Until 10 minutes after drug administration ] [ Designated as safety issue: Yes ]

• Visual analog scale about anxiety to dental treatment [ Time Frame: 10 minutes after drug administration ] [ Designated as safety issue: No ]
• Sedation level [ Time Frame: 10 minutes after drug administration ] [ Designated as safety issue: Yes ]
• Japanese version of STAI [ Time Frame: 10 minutes after drug administration ] [ Designated as safety issue: No ]

Intravenous sedation was used for dealing with transient hypertension, so-called white-coat hypertension, before dental treatment. Midazolam used as a sedative also has antianxiety effect, and the mechanism is guessed that it minimizes patients' stress, resulting in the stability of blood pressure. The purpose of this randomized controlled trial (RCT) is to evaluate the effect of low dose of midazolam on blood pressure and anxiety scale in white-coat hypertensive dental patients.

• Drug: Midazolam
  1. Investigators select subject from patients for whom the doctor has ordered intravenous sedation. Inclusion criteria is SBP>=140mmHg or DBP>=90mmHg measuring when the patient sits on dental chair and has settled down for 5 minutes. Informed consent is obtained from the patient.
  2. Patient conducts Japanese version of STAI and VAS about anxiety to dental treatment.
  3. Investigators take venous line on the upper limb and inject the drug (midazolam at dose of 0.02mg/kg) intravenously. Investigators measure blood pressure, heart rate, and oxygen saturation every 2 minutes until 10 minutes after drug administration.
  4. 10 minutes later, patient conducts Japanese version of STAI and VAS about anxiety to dental procedure again.
  5. Investigators inject an additional sedative agent and the dental treatment is started.
• Drug: Normal Saline Solution (NSS)
  1. Investigators select subject from patients for whom the doctor has ordered intravenous sedation. Inclusion criteria is SBP>=140mmHg or DBP>=90mmHg measuring when the patient sits on dental chair and has settled down for 5 minutes. Informed consent is obtained from the patient.
  2. Patient conducts Japanese version of STAI and VAS about anxiety to dental treatment.
  3. Investigators take venous line on the upper limb and inject the drug (saline solution at dose of 0.004ml/kg) intravenously. Investigators measure blood pressure, heart rate, and oxygen saturation every 2 minutes until 10 minutes after drug administration.
  4. 10 minutes later, patient conducts Japanese version of STAI and VAS about anxiety to dental procedure again.
  5. Investigators inject an additional sedative agent and the dental treatment is started.

• Active Comparator: Midazolam
  Intravenous administration of midazolam at dose of 0.02mg/kg
  Intervention: Drug: Midazolam
• Placebo Comparator: NSS
  Intravenous administration of saline solution at dose of 0.004ml/kg as a placebo drug
  Intervention: Drug: Normal Saline Solution (NSS)

Inclusion Criteria:

SBP>=140mmHg or DBP>=90mmHg measuring when the patient sits on dental chair and has settled down for 5 minutes among dental outpatients scheduling intravenous sedation with American Society of Anesthesiologists physical status I or II.

Exclusion Criteria:

1. Uncontrolled or unstable hypertension
2. Secondary hypertension such as hyperthyroidism and pheochromocytoma
3. Taking sympathomimetic drugs
4. Contraindication of midazolam such as myasthenia gravis and acute narrow-angle glaucoma
5. A pregnant woman or during lactation period
6. Psychiatric disorder such as schizophrenia
7. Not having intelligence enough to read, understand and write a Japanese version of STAI
8. Judged unsuitable by a researcher