DI-THP is also known as tetrahydropalmatine. It possesses analgesic effect that is weaker than that of pethidine and morphine, but it is less addictive and stronger than the ordinary antipyretic analgesics. It has a good effect on chronic persistent dull pain, but poor analgesic effect on trauma or postoperative pain or advanced cancer pain. It has a significant effect on the pain caused by the gastrointestinal system and the hepatobiliary system, and also relieves the labor pain, headache, concussion headache and the like. It is also used to eliminate mental stress such as irritability and anxiety and to treat neurasthenia and insomnia.

Clinical Uses

1. Electrophysiological effects of intravenous injection of dl-THP on supraventricular tachycardia (SVT)

This drug significantly prolongs the AH interval, the effective refractory period of the atrioventricular node, and the Venn’s perimeter of the atrioventricular nodes. No significant effect. It extends the bypass pre-transmission time and the effective refractory period of bypass pre-transmission, significantly prolongs the effective refractory period of the atrium, and it’s 77.8 % effective to prevent the SVT induced by the program electrical stimulation.

2. Antiarrhythmic Effect

(1) It is used in the treatment of atrial fibrillation, such as rheumatic valvular heart disease, coronary heart disease, hypertension.

(2) dl-THP is used for paroxysmal supraventricular tachycardia: intravenous injection of dl-THP makes patients with rapid supraventricular arrhythmia recover fast or slow down their ventricular rate, especially effective for paroxysmal atrial fibrillation. The rate of heart beat after administration was significantly slowed down, which is different from that before administration, and there were no serious side effects.

3. Antihypertensive Effect

dl-THP has good antihypertensive and long-lasting effects, and the systolic blood pressure and diastolic blood pressure are significantly reduced. Its antihypertensive mechanism is to relax blood vessels by inhibiting the voltage-dependent calcium channels present on the smooth muscle cell membrane, and may be related to the blockade of alpha receptor by dl-THP.

4. Tetrahydropalmatine(dl-THP) is used in the treatment of intractable hiccups.

5. Tetrahydropalmatine(dl-THP) is used to treat severe cough.

6. Acupoint injection of dl-THP is also used as a adjuvant therapy in the treatment of autumn diarrhea in children.

7. Combined therapy of Chinese and Western medicine is also used in the treatment of refractory neuropathic headache.

8. dl -THP is used in the treatment of vascular neuropathic headache.

Reference

J. C. Simonsen et al.: The Terpenes, 2nd ed., vols. 1 – 3, Cambridge University Press, New York 1947 – 1951.
A. A. Newmann: Chemistry of Terpenes and Terpenoids, Academic Press, London 1972. T. K. Devon, A. I Scott: Handbook of Naturally Occurring Compounds, vol. II, Terpenes, Academic Press, London 1972.
Terpenoids and Steroids (A Spezialist Periodical Report) vols 1 – 6, The Chemical Society, Burlington House, London 1971 – 1976.