Page 57 - Retail Pharmacy March 2021

CPD ACTIVITY 55 Antibiotic Dosage Duration Counselling / Practice Points Trimethoprim Cephalexin (if above cannot be used) 300mg once daily 500mg every 12 hours 3 days 5 days Elderly may be more susceptible to hyperkalaemia, best taken at night. Dose reduction may be required in renal impairment. Generally well tolerated. Should be avoided in the elderly due to increased risk of blood dyscrasias and skin. disorders, patients should remain well hydrated. Should be taken with food. Not suitable for pyelonephritis, should be dosed at night. Should be taken on empty stomach, patient must remain hydrated, dose reduction may be required in renal impairment. Should be dosed on empty stomach, patient must remain hydrated, dose reduction may be required in renal impairment. Recurrent infection Urine culture is recommended for patients with recurrent infection. With acute episodes of recurrent infection, antibiotic treatment is initiated for seven-14 days with an antibiotic the pathogen is sensitive to. Prophylactic antimicrobials to reduce the frequency and severity of UTI may be considered, along with patient-initiated treatment.13 Evidence from several small studies observing post-menopausal women suggests that antimicrobial prophylaxis reduces the risk of UTI in this population. As with treatment guidelines, prophylaxis treatment guidelines for older adults do not currently exist in Australia. Studies of these patients use the regimen recommended for women under 65 years old.14 Prophylactic antimicrobials are generally reviewed and ceased after a six-month treatment period. Options for continuous prophylaxis in non-pregnant women:17 1. Trimethoprim 150mg at night. 2. Cephalexin 250mg at night. 3. Nitrofurantoin 50mg at night. Patient initiated treatment has been shown to reduce overall use of antibiotics when compared with prophylactic regimens. Patients must be informed to refer to their prescriber if symptoms do not resolve within 48 hours of completing treatment.7 This should be considered only in elderly patients who are cognitively able to manage and appropriately initiate such a regimen. Other strategies to prevent recurrent UTI Where underlying structural abnormalities such as scarring or urethral diverticulum exist and are identified as a causative agent of recurrent UTI, correction of the abnormality through surgery or other means may prove beneficial in reducing UTI occurrence. Regardless of presence of structural abnormality, recurrent UTI patients should be considered for further investigation and referred to a urologist.9 Intravaginal hormone treatment If vaginal atrophy is considered a causative agent of UTI, localised hormone treatment may be warranted. Intravaginal oestrogen in the form of a pessary or cream is inserted into the vagina nightly for two to three weeks and twice weekly thereafter. Intravaginal oestrogen has been shown to improve vaginal flora and decrease the incidence of recurrent UTI in post- menopausal women. Treatment should be reassessed every 12 months.19 TO PAGE 56 Nitrofurantoin 100mg every 6 hours 5 days Elderly more likely to experience peripheral polyneuropathy, chronic pulmonary toxicity, best taken with food. If culture found to be resistant and symptoms not improving Amoxicillin Trimethoprim/ sulfamethoxazole Amoxicillin/ clavulanic acid 500mg every 8 hours 160/800mg every 12 hours 500/125mg every 12 hours 5 days 3 days 5 days If culture found to be resistant to all of above Fosfomycin Norfloxacin Ciprofloxacin 3g 400mg every 12 hours 250mg every 12 hours Single dose 3 days 3 days Table 4. Antibiotic treatment recommendations for acute cystitis in women 17,19 outlined in Table 4. Significant improvement of UTI should be observed within 48 hours of initiating antibiotic therapy. If no change is observed at this time, sensitivity of urine culture should be assessed.17 A Cochrane review of antibiotic treatment for uncomplicated UTI in elderly women found that regimens lasting three to six days were sufficient. Longer treatment regimens of seven to 14 days were found to be no more effective but had an increased rate of adverse drug reactions.18 Complicated and male UTI treatment regimens require an increase in duration to seven-14 days, depending on condition, and could require intravenous antibiotics. It should be noted that male UTIs are less common, and bacterial prostatitis should be excluded before treating for UTI. Unless bacterial prostatitis has been excluded, nitrofurantoin is not recommended in men, due to limited penetration into the inflamed prostate.17,19 In the case of Catheter-associated Urinary Tract Infections (CAUTI), empirical treatment is not recommended due to the high variability of pathogens involved. Consideration should be given to changing or removing the catheter. Resistance of E. coli and other organisms to trimethoprim and other agents is increasing, further stressing the importance of following recommendations in the Therapeutic Guidelines to prevent further resistance.4,17 Other treatments Overseas guidelines suggest ACF patients should be treated for dehydration when commencing antibiotic treatment for UTI. Similar advice to increase water intake should also be provided to community- based elderly patients, to reduce discomfort and stinging during urination2. Urinary alkalinisers do not treat infection but may relieve discomfort. The safety and efficacy of these agents for symptomatic treatment of UTI is yet to be established. Urinary alkalinisers should not be used in patients undergoing treatment with nitrofurantoin as they significantly decrease its efficacy. Concomitant urinary alkalinisers and fosfomycin or quinolones, such as norfloxacin and ciprofloxacin, should also be avoided due to risk of crystaluria. The RACGP Aged Care Guidelines do not support the use of urinary alkalinisers20. Probiotics, cranberry products and methenamine hippurate are not effective in the treatment of UTI and are not recommended.12,21,22 Elderly patients should be assessed for pain relating to the infection and offered analgesia if required. Paracetamol and non- steroidal anti-inflammatories (NSAIDs) are the analgesics of choice. However, paracetamol may be considered in preference to NSAIDs in elderly patients due to increased risk of adverse effects and increased likelihood of renal impairment with dehydration19. RETAIL PHARMACY • MAR 2021