Prophylactic agent

With the availability of NSAIDs with COX-2 selectivity, clinicians postulated that these agents would avoid the need to add an additional prophylactic agent to therapy in patients with PUD risk factors. However, selective COX-2 inhibitors have not been shown to be any more effective than the combination of a PPI and a non-selective NSAID in reducing the incidence of ulcers, and questions remain regarding their long-term cardiovascular safety. 

Assess suitability of chosen prophylactic agents (e.g., drug allergies, CMV donor, and recipient serostatus). 

Assess the need for continuous antihyperuricemic therapy. Use patient factors such as comorbidities to select an agent. Allopurinol is the standard prophylactic agent used in the United States. 

Trespi E, Colla C, Belloni G, Pollino MG, Magnani L, Panizza P, Venturini A Efficacy of rifaximin as a prophylactic agent for the prevention of spontaneous bacterial peritonitis in alcoholic patients. Ital J Gastroenterol Hepatol 1999 31 534A. 

The answer is b. (Hardman, p 1159.) Rifampin inhibits RNA synthesis in bacteria, mycobacteria, and chlamydiae by binding to the DNA-de pen dent RNA polymerase it also inhibits assembly of poxvirus particles. Rifampin is used as a single prophylactic agent for contacts of people with meningococcal or H. influenzae type b infections. Otherwise, it is not used alone because 1 in 10 organisms in a population exposed to rifampin will become resistant, possibly because of mutation or a barrier against rifampin s entry into cells. 

SSRIs in doses of dolasetron 12.5 mg, granisetron 0.1 mg, ondansetron 1 mg, or tropisetron 0.5 mg are recommended in patients who experience PONV despite prophylactic dexamethasone or when no prophylactic agent was used. 

This agent is effective as both a therapeutic and prophylactic agent in patients with recurrent UTIs. Main advantage is the lack of resistance even after long courses of therapy. Adverse effects may limit use (Gl intolerance, neuropathies, pulmonary reactions). 

Because efficacy of various prophylactic agents appears to be similar, drug selection is based on side-effect profiles and comorbid conditions of the patient. Individual response to a particular agent is unpredictable, and a... 

Verapamil provided only modest benefit in decreasing the frequency of attacks in two placebo-controlled studies. It has little effect on the severity of migraine attacks. It is generally considered a second- or third-line prophylactic agent. 

Feverfew appears to be used predominantly as a prophylactic agent in both migraine [2, p. 41] and arthritis [3, p. 48], although there are incidental... 

The failure of physostigmine to reverse BZ effects during the first 8 hours (Fig. 8) is interesting and unexplained. It reminds one of the Berry and Davies findings (in 1970 at the British labs in Porton Down) which showed that the reversible anticholinesterase pyridostigmine was paradoxically effective as a prophylactic agent in the event of nerve gas exposure (see ref. ). 

Mefloquine is also a 4-aminoquinoline. It is a blood schizonticide active against the asexual stages of all malaria parasites. Mefloquine is currently the prophylactic agent of choice for short-term travellers. Resistance of P. falciparum against mefloquine has occurred in South-East Asia. Only an oral... 

VLa.2,6. Other antimalarials. Doxycydine (see Section ILb) is a useful and effective short-term prophylactic agent for travellers to chloroquine-resistant areas and can be used as an alternative when mefloquine or proguanil is unavailable or mefloquine is contraindicated. In combination with quinine also tetracycline is used as an antimalarial. 

Patients with frequent relapses despite apparently adequate prophylactic treatment should be reviewed carefully. Associated milk intolerance or coeliac disease need treatment on their merits. Colonoscopic evidence of dysplasia raises the question of undiagnosed malignancy. Occasionally the prophylactic agents themselves can cause watery diarrhoea (particularly olsalazine) or a hypersensitivity colitic disease. Prophylactic azathioprin should be considered in those in whom relapse is frequent despite use of aminosalicylates or if they are poorly tolerated. In the effective dose of 2 mg/kg adverse effects of bone marrow depression are uncommon, but still occur, and regular haematological review is essential (monthly or bi-monthly). Azathioprin-induced pancreatitis is an uncommon but well-recognised entity. 

A 24-year-old AIDS patient is interested in starting chemoprophylaxis for Pneumocystis pneumonia (PCP) and cerebral toxoplasmosis. He has no drug allergies. Which of the following prophylactic agents is appropriate for the prevention of both PCP and cerebral toxoplasmosis ... 

The Centers for Disease Control s (CDC) Immunization Practices Advisory Committee recommends annual vaccination as the method of choice in the prevention of influenza infection. However, when vaccination is contraindicated or early vaccination is not possible, amantadine and rimantadine are effective prophylactic agents that have been shown to protect approximately 70 to 90% of patients from influenza A infection. Since these drugs do not prevent the host immune response to influenza A, they may be used to prevent infection during the 2- to 4-week period required to develop immunity following vaccination. An additional use of amantadine, unrelated to its antiviral activity, is in the therapy of Parkinson s disease (see Chapter 31). 

To our knowledge, there have been no reports of controlled clinical trials of valproate as a prophylactic agent in bipolar disorder. Results from a number of open trials suggest that perhaps half of patients treated with valproate experience prophylactic benefit (reviewed in Keck et al. 1992a]. A placebo-controlled, double-blind study of the efficacy of the divalproex form of valproate is under way and may provide additional information regarding the use of this drug in the maintenance therapy of bipolar disorder. 

From the above discussion, it appears that both lithium and valproate are equally effective pharmacological treatments for acute mania. Lithium is also established as an effective prophylactic agent, particularly for prevention of... 

Baastrup P, Schou M. Lithium as a prophylactic agent. Arch Gen Psychiatry 1967 16 162-172. 

Affective patients and healthy control subjects rated life as more satisfying at present than in the past, and they also rated themselves higher than most others on scores of life satisfaction at present. The authors concluded that neither lithium as a prophylactic agent nor the affective illness interfered with either the manifest functioning or the patients feelings of satisfaction while in remission. 

For patients with bipolar affective disorder (manic-depressive illness) lithium, usually in the form of lithium carbonate, has been the main prophylactic agent for the last forty years. However, during the last ten years certain anticonvulsants (carbamazepine and sodium valproate) have also been found to be effective. 

In the treatment of S haematobium, an oral dose of 7.5-10 mg/kg is given three times at 14-day intervals. Cure rates on this schedule are 44-93%, with marked reductions in egg counts in those not cured. Metrifonate was also effective as a prophylactic agent when given monthly to children in a highly endemic area, and it has been used in mass treatment programs. In mixed infections with S haematobium and S mansoni, metrifonate has been successfully combined with oxamniquine. 

Mycophenolate mofetil is used for tissue transplantation in combination with tacrolimus or cyclosporine or sirolimus plus glucocorticoids. It is used more than any other cytotoxic drug either at the time of the transplant or following the initiation of acute rejection. Mycophenolate mofetil is a prophylactic agent and cannot be used for chronic rejection or ongoing acute rejection. 

Detoxication of Metals. Pectins or pectin derivatives have been proposed as antidotes for heavy metal poisoning for nearly 200 years. Kertesz (9) has reviewed the early work in this area. Pectin complexes lead so strongly as to quantitatively remove it from solution. Absorption 6f lead, arsenic, and selenium by several animal species has been reduced by pectin- or apple-containing diets. Use of pectin as a prophylactic agent in lead poisoning continues to be of interest. Bondarev (88) recently reported an increase in excretion and a decrease in bone accumulation of lead when rats fed 6 mg/day of lead also received 72-432 mg/day of low ester pectin. Paskins-Hurlburt et al. (89) achieved an 87% decrease in lead absorption by pectate fed rats. These studies bear out the early observations of Fellenburg (see 9, p. 572), who concluded that pectin of decreased ester content would have an enhanced ability to complex metals. 

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