Mezavant in Moscow
The Mezavant tablet has a core containing mesalazine (5-aminosalicylic acid, 5-ASA) in a multicomponent matrix. The core is surrounded by a shell of methacrylic acid copolymers of types A and B; The coating is designed so that the release of mesalazine begins only when the pH reaches above 7.
The mechanism of action of mesalazine is not fully understood, but it is believed that mesalazine (5-ASA) has a local effect, so the clinical effect of the drug does not correlate with the pharmacokinetic characteristics of the substance. The main route of elimination of mesalazine is metabolism to N-acetyl-5-aminosalicylic acid, which is pharmacologically inactive.
Suction
Studies using γ-scintigraphy have shown that after a single dose of 1.2 g of the drug by healthy volunteers on an empty stomach, mesalazine quickly and unchanged passes through the upper gastrointestinal tract. In this case, traces of 14C-labeled mesalazine are detected throughout the colon, which indicates the entry of mesalazine into these parts of the gastrointestinal tract. Complete disintegration of the Mezavant tablet and release of mesalazine was observed after approximately 17.4 hours.
After a single dose of 2.4 or 4.8 g to healthy volunteers for 14 days, mesalazine absorption was 21–22% of the dose taken.
After a single dose of the drug by healthy volunteers on an empty stomach at a dose of 1.2; 2.4 and 4.8 g, the concentration of mesalazine in plasma was determined 2 hours after administration and reached its maximum value after 9–12 hours. Pharmacokinetic parameters showed wide variability. The level of systemic exposure of mesalazine - AUC - when taking the drug in the range from 1.2 to 4.8 g was proportional to the dose taken. Cmax of mesalazine in plasma in the dose range from 1.2 to 2.4 g increased approximately in direct proportion, while from 2.4 to 4.8 g it increased less than increasing doses.
When studying single and multiple doses of the drug at a dose of 2.4 and 4.8 g with regular food, mesalazine was detected in the blood plasma after 4 hours, reaching Cmax 8 hours after a single dose.
A single dose of Mezavant 4.8 g with a fatty meal was accompanied by a slower absorption phase. Under these conditions, mesalazine was detected in the blood plasma approximately 6 hours after administration. However, a high-fat meal increased systemic mesalazine exposure (mean Cmax by 91%, mean AUC by 16%) compared with fasting levels.
Distribution
Mezavant is believed to have a similar distribution profile to other mesalazine-containing drugs. Mesalazine has a relatively small Vd of approximately 18 L, indicating minimal systemic distribution. At mesalazine plasma concentrations of up to 2.5 μg/ml and N-acetyl-5-aminosalicylate concentrations of up to 10 μg/ml, the substances were bound to plasma proteins by 43 and 78–83%, respectively.
Metabolism
The only important metabolite of mesalazine is the pharmacologically inactive N-acetyl-5-aminosalicylic acid. It is formed under the action of N-acetyltransferase-1 in liver cells and the cytosol of intestinal mucosal cells.
Removal
Absorbed mesalazine is excreted mainly by the kidneys after acetylation to N-acetyl-5-aminosalicylic acid. However, the drug is excreted in small quantities by the kidneys and unchanged. Of the 21–22% of the absorbed dose of the drug, less than 8% of mesalazine is excreted unchanged in the urine within 24 hours. About 13% is excreted within 4 hours in the form of N-acetyl-5-aminosalicylic acid. The apparent T1/2 of mesalazine and its main metabolite after taking the drug at a dose of 2.4 and 4.8 g averaged 7–9 and 8–13 hours, respectively.
Special categories of patients
There are no data on the use of Mezavant in patients with impaired liver function. After a single dose of Mezavant 4.8 g, systemic exposure of mesalazine in elderly patients (over 65 years of age, mean creatinine clearance 68–76 ml/min) was greater than that in younger patients (18–35 years, mean creatinine clearance 124 ml/min). min) up to 2 times. The level of systemic exposure is inversely proportional to renal function, assessed by creatinine clearance. This should be taken into account when treating elderly patients with Mezavant.
In patients with impaired renal function, a decrease in the rate of elimination and an increase in the concentration of mesalazine in the blood plasma may be observed, which may be accompanied by an increased risk of unwanted adverse reactions from the urinary system.
In women, the AUC of mesalazine was 2 times greater than in men.
Based on limited pharmacokinetic data, the pharmacokinetics of 5-ASA and N-acetyl-5-ASA are believed to be similar in Southern European and Hispanic subjects.
My 3 months without Mezavant
Crushed Mezavant tablet
Yes, I didn’t write about it here, I only occasionally mentioned it in a Telegram chat. Why? Because I was not sure of the rationality of this action.
Around the beginning of October, I just somehow took and stopped taking Mezavant - the same medicine that I had been consuming almost non-stop since mid-2013 (except for the period on Remicade). If you ask me “why”, I will answer “I’m tired of it”. But why exactly I’m tired of it - more on that below.
I can’t count how many times I have written here on the site that you should not self-medicate, and also stop taking medications prescribed by your doctor. However, paradoxically, I myself have not followed these precepts since the end of Remicade therapy (remember the notes about reducing dosages and subsequent abandonment of Azathioprine, taking herbal remedies, etc.). And I again urge you not to follow my path! Don't stop taking your medications!
So, in October it somehow happened that I just didn’t take Mezavant for a week. There was a difficult period at work, home renovations, and somehow everything was wrapped up... Well, you understand. In general, when I finally remembered about the medicine and went into the room to take a couple of tablets, I suddenly realized that during this week my bowel movements had become much better, although I had not changed anything at all either in my diet or in my general lifestyle. Paradox? Paradox. I decided that the chair couldn’t just suddenly improve on its own, and therefore I decided to live without Mezavant for another couple of days.
Another week passed and I felt great. Although, it would seem, 2013 is still quite clearly visible in my head - total damage to the large intestine, pseudopolyps, ulcers, repeated trips to the toilet with clean blood, loss of 30% of body weight, and everything else that goes along with it. However, when I stopped taking Mezavant, I was fully aware of my actions, realizing that one fine morning I might see blood in the toilet.
In the wake of the periodic desire to still resume taking my favorite mesalazine-containing medication, the whole of October passed. And then work hit me with renewed vigor, and there was no time to philosophize about the correctness of my decision.
In fact, another reason for hiding this news from the public was the reluctance to revive the feeling of anxiety among my loved ones, because... everyone remembers what I looked like 5.5 years ago, and it would be stupid, out of my own stupidity, to return to the origin of coordinates again.
Today is January 28, 2022 and I feel absolutely amazing. I remember how in 2013, a grandfather from the cardiology department was admitted to our ward, who had no dietary restrictions, and how at night, while everyone was sleeping, he ate smoked sausage. You should have heard that smell... And last night I ate three sandwiches with that damned sausage and cheese.
Perhaps it is too early to judge the correctness of my decision. If with Azathioprine and Remicade I can already say with confidence that nothing terrible happened after they were discontinued, then in the case of Mezavant too little time has passed. And I once again advise you not to stop taking medications without permission!
Well, how can we not remind you about the application? 
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