Dipyrone increases the blood flow of arterial dorsal skin flaps

Comparative Effects of Metamizole (Dipyrone) and Naproxen on Renal Function and Prostacyclin Synthesis in Salt-Depleted Healthy Subjects - A Randomized Controlled Parallel Group Study

Aim: The objective was to investigate the effect of metamizole on renal function in healthy, salt-depleted volunteers. In addition, the pharmacokinetics of the four major metamizole metabolites were assessed and correlated with the pharmacodynamic effect using urinary excretion of the prostacyclin metabolite 6-keto-prostaglandin F1α. Methods: Fifteen healthy male volunteers were studied in an open-label randomized controlled parallel group study. Eight subjects received oral metamizole 1,000 mg three times daily and seven subjects naproxen 500 mg twice daily for 7 days. All subjects were on a low sodium diet (50 mmol sodium/day) starting 1 week prior to dosing until the end of the study. Glomerular filtration rate was measured using inulin clearance. Urinary excretion of sodium, potassium, creatinine, 6-keto-prostaglandin F1α, and pharmacokinetic parameters of naproxen and metamizole metabolites were assessed after the first and after repeated dosing. Results: In moderately sodium-depleted healthy subjects, single or multiple dose metamizole or naproxen did not significantly affect inulin and creatinine clearance or sodium excretion. Both drugs reduced renal 6-keto-prostaglandin F1α excretion after single and repeated dosing. The effect started 2 h after intake, persisted for the entire dosing period and correlated with the concentration-profile of naproxen and the active metamizole metabolite 4-methylaminoantipyrine (4-MAA). PKPD modelling indicated less potent COX-inhibition by 4-MAA (EC₅₀ 0.69 ± 0.27 µM) compared with naproxen (EC₅₀ 0.034 ± 0.033 µM). Conclusions: Short term treatment with metamizole or naproxen has no significant effect on renal function in moderately sodium depleted healthy subjects. At clinically relevant doses, 4-MAA and naproxen both inhibit COX-mediated renal prostacyclin synthesis.

The Role of Cyclooxygenase Enzymes in the Effects of Losartan and Lisinopril on the Contractions of Rat Thoracic Aorta

OBJECTIVE

It was suggested that prostaglandins which are synthesized by cyclooxygenase (COX) enzymes contribute to the actions of angiotensin-converting enzyme (ACE) inhibition and angiotensin AT1 receptor antagonism and there is an interaction between ACE signaling pathway and COX enzymes. We aim to investigate the role of COX enzymes in the effects of losartan, an angiotensin II (Ang II) receptor antagonist or lisinopril, an ACE inhibitor, on the contractions of rat thoracic aorta in isolated tissue bath.

MATERIALS AND METHODS

Responses of losartan (10^-6, 10^-5, 10^-4 M), lisinopril (10^-6, 10^-5, 10^-4 M), and non-selective COX inhibitor dipyrone (10^-4, 7 × 10^-4, 2 × 10^-3 M) alone to the contractions induced by phenylephrine (Phe) (10^-7 M), potassium chloride (KCl) (6 × 10^-2 M), Ang II (10^-8 M) and responses of losartan or lisinopril in combination with dipyrone to the contractions induced by Phe or KCl were recorded.

RESULTS

When used alone, dipyrone and losartan inhibited Phe, KCl, and Ang II-induced contractions, whereas lisinopril inhibited only Phe and Ang II-induced contractions. Inhibition of COX enzymes (COX-3, COX-3 + COX-1, COX-1+ COX-2 + COX-3 by dipyrone 10^-4, 7 × 10^-4, 2 × 10^-3 M, respectively) augmented the relaxant effects of losartan or lisinopril. Also, dipyrone potentiated the effect of lisinopril on KCl-induced contractions.

CONCLUSION

We suggest that dipyrone increases the smooth-muscle relaxing effects of losartan or lisinopril and that COX enzyme inhibition may have a role in the enhancement of this relaxation.

Metamizole: an effective solution for vasospasm

OBJECTIVE

Vasospasm is a major problem during microsurgery, and a variety of pharmacological agents are used to alleviate vasospasm. This study aimed to demonstrate the effect of metamizole on vasospasm and to compare it with lidocaine and papaverine, both of which are commonly used to correct vasospasm.

METHODS

Thirty-five female rats were randomly divided into four groups: Group 1, 2, 3, and 4, which were the control (n = 8), metamizole (n = 9), papaverine (n = 9), and lidocaine (n = 9) treatment groups, respectively. Both femoral arteries of all of the rats were dissected, and they were immediately photographed. The pharmacological agents or saline in the control group were topically applied to the arteries, accordingly. The arteries were photographed again at time points 5, 10, 20 and 30 minutes after application of the agents. The images were transferred to a computer and the arteries' diameters were measured in mm.

RESULTS

All of the pharmacological treatments increased the diameter of the arteries significantly during the observation period. However, comparison between the groups indicated that metamizole and papaverine produced significantly more vasodilation than the lidocaine group, for all time points measured after application.

CONCLUSION

These findings show that topically applied metamizole is as effective as papaverine at alleviating vasospasm during the 30 minutes time interval. This administration may be considered as a good alternative to correct vasospasm during microsurgery.