What Is Midazolam?
1-methyl-8-chloro-6- (2-fluorophenyl) -4H-imidazo [l, 5-a] [l, 4] benzodiazepine
- Midazolam is used to treat insomnia, and can also be used to induce sleep during surgery or diagnostic tests.
- Drug name
- Midazolam
- Drug type
- Essential medicines
- English name
- Midazolam
- Chinese alias
- Midazolam; Midazolam
- English alias
- Ro-21-3981
Midazolam chemical name
- 1-methyl-8-chloro-6- (2-fluorophenyl) -4H-imidazo [l, 5-a] [l, 4] benzodiazepine
Midazolam molecular structure
Midazolam molecular formula
- C18H13C1FN3
Midazolam molecular weight
- 325
Physicochemical Properties of Midazolam
- This product is white to slightly yellow crystalline or crystalline powder; odorless; yellow to light when exposed to light. Soluble in glacial acetic acid or ethanol, soluble in methanol, and almost insoluble in water. Melting point is 160-164 ° C.
Midazolam Pharmacology
- This product has a typical benzodiazepine pharmacological activity, which can produce anxiolytic, sedative, hypnotic, anticonvulsant and muscle relaxation effects. After intramuscular or intravenous injection, a transient antegrade memory loss can occur, preventing patients from recalling what happened during the peak of the drug. This product is characterized by fast onset and short duration. After taking the medicine, the time to fall asleep can be shortened (usually 20 minutes from taking the medicine to falling asleep), and the total sleep time is extended without affecting fast wave sleep (REM). After waking up in the morning, the patient can feel energetic, relaxed and happy. No resistance or withdrawal symptoms or rebound. Low toxicity and large safety range. The oral and intramuscular injections of this product are quickly and completely absorbed, and can be distributed throughout the body. The volume of distribution is 1 to 2 L / kg. In patients with congestive heart failure, the volume of distribution will increase by 2 to 3 times, and that of obese patients will increase. The plasma protein binding rate of this product is 97%. It is inactivated by liver metabolism or combined with glucuronic acid, and finally excreted from the kidney. Plasma concentration can be divided into two phases, the distribution phase is 10 minutes, the elimination phase t1 / 2 is 1.5 to 2.5 hours, and the t1 / 2 of patients with congestive heart failure can be prolonged 2 to 3 times. There is no accumulation of long-term medication, and pharmacokinetic data and metabolism remain unchanged.
Midazolam indications
- It is used to treat insomnia, and can also be used to induce sleep during surgical operations or diagnostic tests.
Midazolam usage and dosage
- Due to different dosage forms and specifications, please read the drug instructions carefully or follow the doctor's advice.
Midazolam adverse reactions
- Common adverse reactions include hypotension, delirium, hallucinations, palpitations, rash, excessive ventilation, and rare adverse reactions include blurred vision, headache, dizziness, weakness in hands and feet, and tingling sensation. In addition, there are increased heart rate, thrombophlebitis, skin redness, and respiratory depression.
Midazolam contraindications
- Women who are allergic to benzodiazepines within the first 3 months of pregnancy are contraindicated.
Midazolam precautions
- (1) Intramuscular injection can cause local induration and pain; intravenous tenderness after intravenous injection. (2) During anesthesia or surgery, 10.8% to 23.3% of patients may have reduced respiratory volume and respiratory rate, and intravenous injection may cause respiratory depression in 15% of patients. The elderly and long-term users are prone to severe respiratory depression. Most of the effects on respiratory function are caused by too high a dose or too fast an intravenous injection, so the speed of intravenous injection should not be too fast, generally lmg / ml per minute. Patients with organic brain injury, severe respiratory insufficiency, the elderly, or patients with circulatory system disease, will be hospitalized for observation within 3 hours after administration. Be careful with injections. (3) After long-term use for sedation, patients may develop psychomotor disorders, muscle tremors, uncontrollable movements or beats of the body, rare excitement, and inability to be quiet. It is not suitable for insomnia in patients with schizophrenia or major depression. Do not drive or operate the machine within 12 hours of taking the medicine. In patients with chronic obstructive pulmonary disease, severe pulmonary insufficiency may occur due to respiratory depression. (4) Myasthenia gravis and other neuromuscular junction diseases, muscular dystrophy, muscle rigidity, etc. Use this product to aggravate symptoms, use with caution. (5) For patients with chronic renal failure, the peak concentration of midazolam is higher than that of normal people, the induction of anesthesia occurs faster, and the recovery is prolonged. (6) It can enhance the effect of central inhibitory drugs, and it can also enhance the effect when combined with alcohol. Therefore, do not drink alcoholic beverages within 12 hours before and after using this product.
Midazolam drug interactions
- (1) When used in combination, it can enhance the effect of central inhibitory drugs and alcohol, so do not drink alcoholic beverages within 12 hours after using this product. (2) In combination with cimetidine and ranitidine, the plasma concentration of midazolam increased. (3) The antihypertensive effect of antihypertensive drugs can be enhanced when combined.
Midazolam
- Injection: 1ml: 5mg, 2ml: 10mg
Midazolam Pharmacopeia Introduction
- [Identification] (1) Take this product and the midazolam reference product, add methanol to dissolve and dilute each solution to make a solution containing about 10 pi per lml as the test solution and reference solution, according to the relevant substance For chromatographic conditions, the retention time of the main peak of the test solution should be consistent with the retention time of the main peak of the reference solution. (2) The infrared absorption spectrum of this product should be consistent with the control spectrum (spectrum set 1084). (3) This product shows the identification reaction of organic fluoride (Appendix III). (4) Take 2ml of the absorbing solution prepared under the item of identification (3), and show the response of the identification of chloride (2) (Appendix III). [Inspection] The clarity and color of the acidic solution is 0.10g. After adding 0.1ml / L hydrochloric acid solution to dissolve 10ml, the solution should be clear and colorless. (Appendix A, first method) comparison must not be deeper. Relevant substances are taken from this product, dissolved in methanol and diluted to make a solution containing 1 mg per 1 ml as the test solution; 1 ml is precisely measured, placed in a 100 ml measuring flask, diluted to the mark with methanol, shaken, and used as a control solution. Tested according to high performance liquid chromatography (Appendix VD), using octylsilane-bonded silica gel as the filler; acetate buffer solution (take 7.7 g of ammonium acetate and 10 ml of 40% tetrabutyl ammonium hydroxide solution, dissolve and dilute with water To 1000ml, adjust the pH to 5.3) -methanol (44:56) as the mobile phase with glacial acetic acid; the detection wavelength is 254nm. Take the appropriate amount of midazolam reference substance and N-dealkyl fluazepam impurity reference substance, dissolve it in methanol and make a solution containing about 10 µg per ml. As a system suitability test solution, take 10 µl of the injection solution. Phase chromatograph, record the chromatogram, the resolution of the midazolam peak and the N-dealkyl fluoxazim peak should be greater than 4.0; take 10 l of the control solution and inject it into the liquid chromatograph, adjust the detection sensitivity to make the main component peak high Approximately 20% of full scale; accurately measure 10µl of each of the control solution and test solution, and inject them into the liquid chromatograph respectively, and record the chromatogram to 2.5 times the peak retention time of the main component. If there are impurity peaks in the chromatogram of the test solution, the area of a single impurity peak must not be greater than 0.2 times (0.2%) the main peak area of the control solution, and the sum of the peak areas of each impurity must not be greater than 0.5 times (0.5%) the main peak area of the control solution. . Any peak in the test solution that is less than 0.05 times the main peak area of the control solution is ignored. Loss on drying Take this product and dry it to constant weight at 105 ° C. Lose weight should not exceed 0.5% (Appendix L). Take 1.0g of this product and check it according to law (Appendix N). The remaining residue should not exceed 0.1%. The heavy metal shall be taken as the residue left under the burning residue, and shall be inspected in accordance with the law (Appendix H Second Law). The content of heavy metal shall not exceed 20 parts per million. [Content determination] Take about 0.12g of this product, accurately weigh, add 30ml of glacial acetic acid to dissolve, add 20ml of acetic anhydride, according to potentiometric titration method (Appendix A), and use perchloric acid titration solution (0.1mol / L) Titrate and correct the results of the titration with a blank test. Each 1ml of perchloric acid titration solution (0.1mol / L) is equivalent to 16.29mg of C18H13C1FN3. [Category] Anesthetic. [Storage] shading and sealed.