Methenamine mandelate

How many milliliters of methenamine mandelate oral suspension containing 250 mg and 500 mg per 5 mL should be used in preparing a liter of a suspension containing 60 mg of methenamine mandelate per mL ... 

Methenamine salts methenamine (hexamine) methenamine mandelate... 

Methenamine mandelate is a salt of mandelic acid and methenamine and both of these possess property of urinary antiseptic. It is rapidly absorbed in gastrointestinal tract and excreted unchanged in urine, where it broken down in acidic pH (< 5) of urine and formaldehyde is released, which inhibits most of the bacteria. It is administered with sodium biphosphate, mandelic acid or ascorbic acid to keep the urinary pH below 6. Its use is restricted to chronic, resistant type of UTI. 

Methenamine mandelate is the salt of mandelic acid and methenamine and possesses properties of both of these urinary antiseptics. Methenamine hippurate is the salt of hippuric acid and methenamine. Below pH 5.5, methenamine releases formaldehyde, which is antibacterial. Mandelic acid or hippuric acid taken orally is excreted unchanged in the urine, in which these drugs are bactericidal for some gram-negative bacteria when pH is less than 5.5. 

Methenamine mandelate, 1 g four times daily, or methen-amine hippurate, 1 g twice daily by mouth (children, 50 mg/kg/d or 30 mg/kg/d, respectively), is used only as a urinary antiseptic to suppress, not treat, urinary tract infection. Acidifying agents (eg, ascorbic acid, 4-12 g/d) may be given to lower urinary pH below 5.5. Sulfonamides should not be given at the same time because they may form an insoluble compound with the formaldehyde released by methenamine. Persons taking methenamine mandelate may exhibit falsely elevated tests for catecholamine metabolites. 

The action of methenamine mandelate or hippurate is nonspecific against many different microorganisms and consists of the simultaneous effects of formaldehyde and acidity. Microorganisms such as proteus that make a strongly alkaline urine through release of ammonia... 

Topical antibiotics with a narrow spectrum of action and low toxicity (eg, bacitracin and mupirocin) can be used for temporary control of bacterial growth and are generally preferred to antiseptics. Methenamine mandelate releases formaldehyde in a low antibacterial concentration at acid pH and can be an effective urinary antiseptic for long-term control of urinary tract infections. 

Adverse effects The side effects include gastrointestinal distress. At higher doses, albuminuria, hematuria and rashes may develop. Methenamine mandelate is contraindicated in treating patients with renal insufficiency, because mandelic acid may precipitate. Sulfonamides react with formaldehyde and must not be used concomitantly with methenamine. 

Methenamine Methenamine Hippurate Methenamine Mandelate Method I USP (24, pp. 1062, 1063 and 1064)... 

Urinary pH can be important in determining dmg toxicity more directly. A preparation containing methenamine mandelate and sul-famethizole caused turbidity in the urine of 9 out of 32 patients. The mrbidity was higher in acidic urine, and was caused by precipitation of an amorphous sulfonamide derivative containing 63% of sulfamethizole. In vitro, methenamine causes the precipitation of the sulfonamide at pH values from 5 to 6. The... 

J. H. Lipton. Incompatibility between suliamethi-zole and methenamine mandelate. N. Engl. J. Med., 268, 92-3 (1963)... 

Methenamine Mandelate, USP. Hexamethylenetetramine mandelate (Mandclamine) is a while crystalline powder with a sour la.ste and practically no odor. It is very soluble in water and has the advantage of providing its own aeidily. although in its use the custom is to carry out a preliminary acidificatiun of the urine for 24 to. 16 hours before admini.s-... 

Intermittent self-catheterization with or without a concomitant anticholinergic agent is recommended in patients with large postvoid urine residual volumes (>100 mL) or when the urinary problem is hyporeflexic in nature (failure to empty). Patients with large postvoid residual volumes are at risk for developing urinary tract infections and often are prescribed urinary acidifiers such as vitamin C or antiseptics such as methenamine mandelate to prevent infections. 

Methenamine is an antiinfective agent. In acidic urine, methenamine is hydrolyzed to ammonia and formaldehyde, which is bactericidal to certain bacteria in urine. Acid salts (methenamine mandelate and hippurate) have some nonspecific bacteriostatic activity and help to maintain low nrine pH. It is indicated in suppression or elimination of bacterinria associated with pyelonephritis, cystitis, and other chronic UTls in treatment of infected residual urine, sometimes accompanying nenrologic disease or diabetes. 

METHENAMINE MANDELATE (Mandameth, Mandelamine, Mandelamine Forte Suspension)... 

FIGURE 65 Methenamine mandelate decomposes in solution to generate formaldehyde, which inhibits all bacteria that cause urinary tract infections. Urea-splitting microorganisms raise the pH of the urine and hence inhibit the release of formaldehyde and the action of methenamine. 

Gastrointestinal distress frequently is caused by doses greater than 500 mg fom times a day, even with enteric-coated tablets. Painful and frequent micturition, albuminuria, hematuria, and rashes may result from doses of 4 to 8 g/day given for longer than 3 to 4 weeks. Once the urine is sterile, a high dose should be reduced. Because systemic methenamine has low toxicity at the typically used doses, renal insufficiency does not constitute a contraindication to the use of methenamine alone, but the acids given concurrently may be detrimental. Methenamine mandelate is contraindicated in renal insufficiency. CrystaUuria from the mandelate moiety can occur. Methenamine combines with sulfamethizole and perhaps other sulfonamides in the urine, which results in mutual antagonism. 

Methenamine Mandelate. Mandelamine hexydal-ine hexamethylenetetramine phenylgtycolate hexamethyl-enamine mandelate Mandastat Mandacon Purerin Uro-... 

C. Methenamine Methenamine mandelate and methentunine hippurate combine urine acidification with the release of the antibacterial compound formaldehyde at pH levels below 5.5. These drugs are not usually active against proteus because those organisms alkalinize the urine. Insoluble complexes form between formaldehyde and sulfonamides, and the drugs should not be used together. 

Methenamine salts Methenamine mandelate Methenamine hippurate... 

Methenamine and methenamine mandelate are only effective as urinary antisepties if the pH is about 5.5 or lower, when formaldehyde is released. This is normally achieved by giving urinary acidifiers such as ammonium chloride, ascorbic acid, or sodium acid phosphate. In the case of methenamine hippurate, the acidification of the urine is achieved by the presence of hippuric acid. The concurrent use of substances that raise the urinary pH such as acetazolamide, sodium bicarbonate, potassium or sodium citrate is clearly contraindicated. Potassium citrate mixture BPC has been shown to raise the pH by more than 1 at normal therapeutic doses, thereby making the urine sufficiently alkaline to interfere with the activation of methenamine to formaldehyde. Some antacids (containing magnesium, aluminium or calcium as well as sodium bicarbonate mentioned above) can also cause a significant rise in the pH of the urine. ... 

Methenamine mandelate Methenamine undecylenate Methocarbamol Methoxyflurane p-Methoxythiobenzaldehyde Methsuximide Methyl acetate 6-alpha-Methyl-l 7-acetoxy-progesterone... 

Methenamine mandelate (Hexamine mandelate), C6Hi2N4,C8Hg03, Mol. Wt. 292-3. 

Mandelate (1 1) [587-23-5]. Hexamethylenamine mandelate. Mandelamine. Methenamine mandelate, US AN. Other proprietary names Mp 128-130°. 

Roesel, R.A., Coryell, M.E., Blankenship, P.R., Thevaos, T.G. and Knowlton Hall, W. (1980), Interference of methenamine mandelate in screening for organic and amino acid disorders. Clin. Chim. Acta, 100,55. 

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