Mesalamine (Page 3 of 5)

8.6 Renal Impairment

Mesalamine is known to be substantially excreted by the kidney, and the risk of toxic reactions may be greater in patients with impaired renal function. Evaluate renal function in all patients prior to initiation and periodically while on mesalamine tablets therapy. Monitor patients with known renal impairment or history of renal disease or taking nephrotoxic drugs for decreased renal function and mesalamine-related adverse reactions [see Warnings and Precautions (5.1), Adverse Reactions (6.2),Drug Interactions (7.1)].

10. OVERDOSAGE

Mesalamine is an aminosalicylate, and symptoms of salicylate toxicity may include nausea, vomiting, abdominal pain, tachypnea, hyperpnea, tinnitus, and neurologic symptoms (headache, dizziness, confusion, seizures). Severe intoxication with salicylates may lead to electrolyte and blood pH imbalance, and potentially end organ (e.g., renal and liver) damage.

There is no specific known antidote for mesalamine overdose; however, conventional therapy for salicylate toxicity may be beneficial in the event of acute overdosage and may include gastrointestinal tract decontamination to prevent further absorption. Correct fluid and electrolyte imbalance by the administration of appropriate intravenous therapy and maintain adequate renal function.

Mesalamine is a pH-dependent, delayed-release product and this factor should be considered when treating a suspected overdose.

11. DESCRIPTION

Each mesalamine delayed-release tablet for oral administration contains 1.2 g

5-aminosalicylic acid (5-ASA; mesalamine), an anti-inflammatory agent. Mesalamine also has the chemical name 5-amino-2-hydroxybenzoic acid and its structural formula is:

Image

Molecular formula: C7 H7 NO3

Molecular weight: 153.14

Mesalamine, USP is a light tan to pink colored, needle-shaped crystals. Color may darken on exposure to air. It is odorless or may have a slight characteristic odor.

The tablet is coated with a pH-dependent polymer film, which breaks down at or above pH 6.8, normally in the terminal ileum where mesalamine then begins to be released from the tablet core. The tablet core contains mesalamine with hydrophilic excipients and provides for extended release of mesalamine.

Each mesalamine delayed-release tablet, USP intended for oral administration contains 1.2 g of mesalamine. In addition, each tablet contains the following inactive ingredients: carboxymethylcellulose sodium, colloidal silicon dioxide, hypromellose, iron oxide red, iron oxide yellow, magnesium stearate, methacrylic acid copolymer, microcrystalline cellulose, polyethylene glycol, sodium starch glycolate, triethyl citrate, talc and titanium dioxide.

The Product meets USP Dissolution Test 4.

12. CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

The mechanism of action of mesalamine is not fully understood, but it appears to have a topical anti-inflammatory effect on the colonic epithelial cells. Mucosal production of arachidonic acid metabolites, both through the cyclooxygenase and lipoxygenase pathways, is increased in patients with ulcerative colitis, and it is possible that mesalamine diminishes inflammation by blocking cyclooxygenase and inhibiting prostaglandin production in the colon.

12.3 Pharmacokinetics

Absorption

The total absorption of mesalamine from mesalamine delayed-release tablets 2.4 g or 4.8 g given once daily for 14 days to healthy subjects was found to be approximately 21% to 22 % of the administered dose.

Gamma-scintigraphy studies have shown that a single dose of mesalamine delayed-release tablets 1.2 g (one tablet) passed intact through the upper gastrointestinal tract of fasted healthy subjects. Scintigraphic images showed a trail of radio-labeled tracer in the colon, suggesting that mesalamine had distributed through this region of the gastrointestinal tract.

In a single-dose study, mesalamine delayed-release tablets 1.2 g, 2.4 g and 4.8 g were administered in the fasted state to healthy subjects. Plasma concentrations of mesalamine were detectable after 2 hours and reached a maximum by 9 to 12 hours on average for the doses studied. The pharmacokinetic parameters are highly variable among subjects (Table 4). Mesalamine systemic exposure in terms of area under the plasma concentration-time curve (AUC) was slightly more than dose proportional between 1.2 g and 4.8 g mesalamine delayed-release tablets. Maximum plasma concentrations (Cmax ) of mesalamine increased approximately dose proportionately between 1.2 g and 2.4 g and sub-proportionately between 2.4 g and 4.8 g of mesalamine delayed-release tablets, with the dose normalized value at 4.8 g representing, on average, 74 % of that at 2.4 g based on geometric means.

Table 4 Mean (SD) Pharmacokinetic Parameters for Mesalamine Following Single-Dose Administration of Mesalamine Delayed-Release Tablets Under Fasting Conditions
* Arithmetic mean of parameter values are presented except for Tmax and Tlag .
N=43, N=27, § N=36, Median (min, max), # N=46, Þ N =33

Parameter* of Mesalamine

Mesalamine Delayed-Release Tablets 1.2 g (N=47)

Mesalamine Delayed-Release Tablets 2.4 g (N=48)

Mesalamine Delayed-Release Tablets 4.8 g (N=48)

AUC0-t (ng.h/mL)

9039 (5054)

20538 (12980)

41434 (26640)

AUC0-∞ (ng.h/mL)

9578 (5214)

21084 (13185)

44775§ (30302)

Cmax (ng/mL)

857 (638)

1595 (1484)

2154 (1140)

Tmax (h)

9# (4 to 32.1)

12 (4 to 34.1)

12 (4 to 34)

Tlag (h)

2# (0 to 8)

2 (1 to 4)

2 (1 to 4)

T1/2 (h) (Terminal Phase)

8.56 (6.38)

7.05Þ (5.54)

7.25§ (8.32)

Food Effects

Administration of a single dose of mesalamine delayed-release tablets 4.8 g with a high-fat meal resulted in further delay in absorption, and plasma concentrations of mesalamine were detectable 4 hours following dosing. However, a high-fat meal increased systemic exposure of mesalamine (mean Cmax : increased 91 %; mean AUC: increased 16 %) compared to results in the fasted state. Mesalamine delayed-release tablets were administered with food in the controlled clinical trials [see Dosage and Administration (2)].

In a single and multiple dose pharmacokinetic study of mesalamine delayed-release tablets, 2.4 g or 4.8 g was administered once daily with standard meals to 28 healthy subjects per dose group. Plasma concentrations of mesalamine were detectable after 4 hours and were maximal by 8 hours after the single dose. Steady state was achieved generally by 2 days after dosing. Mean AUC at steady state was only modestly greater (1.1- to 1.4-fold) than predictable from single dose pharmacokinetics.

Distribution

Mesalamine is approximately 43% bound to plasma proteins at the concentration of 2.5 mcg/mL.

Elimination

Metabolism

The only major metabolite of mesalamine (5-aminosalicylic acid) is N-acetyl-5-aminosalicylic acid. Its formation is brought about by N-acetyltransferase (NAT) activity in the liver and intestinal mucosa cells, principally by NAT-1.

Excretion

Excretion of mesalamine is mainly via the renal route following metabolism to N-acetyl-5-aminosalicylic acid (acetylation); however, there is also limited excretion of the parent drug in urine. Of the approximately 21% to 22% of the dose absorbed, less than 8% of the dose was excreted unchanged in the urine after 24 hours, compared with greater than 13% for N-acetyl-5-aminosalicylic acid. The mean renal clearance (CLR ) in adults ranged from 1.8 L/h to 2.9 L/h following single dose administration and ranged from 5.5 L/h to 6.4 L/h after a multiple dosing for 14 days. The apparent terminal half-lives for mesalamine and its major metabolite after administration of mesalamine 2.4 g and 4.8 g were, on average, 7 to 9 hours and 8 to 12 hours, respectively.

Systemic exposures in adult subjects were inversely correlated with renal function as assessed by estimated creatinine clearance [see Use in Specific Populations (8.6)].

Specific Populations

Geriatric Patients

In a single-dose pharmacokinetic study of mesalamine, 4.8 g was administered in the fasted state to 71 healthy male and female subjects (28 young (18 to 35 years); 28 elderly (65 to 75 years); 15 elderly (>75 years)). Increased age resulted in increased systemic exposure (approximately 2-fold in Cmax ) to mesalamine and its metabolite N-acetyl-5-aminosalicylic acid. Increased age resulted in a slower apparent elimination of mesalamine, though there was high between-subject variability.

Table 5 Mean (SD) Pharmacokinetic Parameters for Mesalamine Following Single-Dose Administration of Mesalamine Delayed-Release Tablets 4.8 g under Fasting Conditions to Young and Elderly Subjects
Arithmetic mean (SD) data are presented, N = Number of subjects; 5-ASA = 5-aminosalicylic acid
* N=15, N=16, N=13, § Median (min-max)

Parameter of 5-ASA

Young Subjects (18 to 35 years ) (N=28)

Elderly Subjects (65 to 75 years) (N=28)

Elderly Subjects (75 years and older) (N=15)

AUC0-t (ng.h/mL)

51570 (23870)

73001 (42608)

65820 (25283)

AUC0-∞ (ng.h/mL)

58057* (22429)

89612 (40596)

63067 (22531)

Cmax (ng/mL)

2243 (1410)

4999 (4381)

4832 (4383)

tmax § (h)

22 (5.98 to 48)

12.5 (4 to 36)

16 (4 to 26)

tlag § (h)

2 (1 to 6)

2 (1 to 4)

2 (2 to 4)

t½ (h), terminal phase

5.68* (2.83)

9.68 (7.47)

8.67 (5.84)

Renal clearance (L/h)

2.05 (1.33)

2.04 (1.16)

2.13 (1.20)

Pediatric use information is approved for Takeda Pharmaceuticals U.S.A., Inc.’s LIALDA (mesalamine) delayed-release tablets. However, due to Takeda Pharmaceuticals U.S.A., Inc.’s marketing exclusivity rights, this drug product is not labeled with that information.

Drug Interaction Studies

The potential effect of mesalamine (4.8 g given once daily) on the pharmacokinetics of four commonly used antibiotics were evaluated in healthy subjects. The four antibiotics studied and their dosing regimens were as follows: amoxicillin (single 500 mg dose), ciprofloxacin XR (single 500 mg dose), metronidazole (750 mg twice daily for 3.5 days), and sulfamethoxazole/trimethoprim (800 mg/160 mg twice daily for 3.5 days). The change in Cmax and AUC of amoxicillin, ciprofloxacin and metronidazole when they were coadministered with mesalamine were all 3% or less. There was an increase of 12% in Cmax and an increase of 15% in AUC of sulfamethoxazole when sulfamethoxazole/trimethoprim was coadministered with mesalamine. Coadministration of mesalamine did not result in clinically significant changes in the pharmacokinetics of any of the four antibiotics.

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