USES: Hiprex is indicated in the prophylaxis and treatment of urinary
Therapeutic indications
Hiprex is indicated in the prophylaxis and treatment of urinary
tract infections:
1. As maintenance therapy after successful initial treatment of acute infections with antibiotics.
2. As long-term therapy in the prevention of recurrent cystitis.
3. To suppress urinary infection in patients with indwelling catheters and to reduce the incidence of catheter blockage.
4. To provide prophylaxis against the introduction of infection into the urinary tract during instrumental procedures.
5. Asymptomatic bacteriuria.
Posology and method of administration
Adults: 1g twice daily.
In patients with catheters the dosage may be increased to 1g three times daily.
Children under 6 years: Not recommended.
Children: 6-12 years: 500mg twice daily.
Elderly: No special dosage recommendations.
The tablets may be halved, or they can be crushed and taken with a drink of milk or fruit juice if the patient prefers.
Contraindications
Hepatic dysfunction, renal parenchymal infection, severe dehydration, metabolic acidosis, severe renal failure (creatinine clearance or GFR<10 ml/min.) or gout. Hiprex may be used where mild (20-50 ml/min.) to moderate (10-20 ml/min.) renal insufficiency is present. (If the GFR is not available the serum creatinine concentration can be used as a guide.).
Hiprex should not be administered concurrently with sulphonamides because of the possibility of crystalluria, or with alkalising agents, such as a mixture of potassium citrate
Interaction with other medicinal products and other forms of interaction
Methenamine hippurate should not be given/administered concurrently with sulphonamides because of the possibility of crystalluria, or with alkalising agents such as potassium citrate. Concurrent use with acetazolamide should be avoided as the desired effect of hexamine will be lost.
Pregnancy and lactation
There is inadequate evidence of safety of the drug in human pregnancy but it has been in wide use for many years without apparent ill consequence, animal studies having shown no hazard.
Methenamine is excreted in breast milk but the quantities will be insignificant to the infant. Mothers can therefore breast feed their infants.
Undesirable effects
Occasionally rashes, pruritis,gastric irritation, irritation of the bladder, may occur.
All side effects are reversible on the withdrawal of the drug.
Overdose
Vomiting and haematuria may occur. These can be treated by the use of an anti-emetic and drinking copious quantities of water respectively. Bladder symptoms can be treated by the consumption of copious quantities of water and 2-3 teaspoonfuls of bicarbonate of soda
