Prophylactic effect

Retinoids are needed for cellular differentiation and skin growth. Some retinoids even exert a prophylactic effect on preneoplastic and malignant skin lesions. Fenretlnide (54) is somewhat more selective and less toxic than retinyl acetate (vitamin A acetate) for this purpose. It is synthesized by reaction of all trans-retinoic acid (53), via its acid chloride, with g-aminophe-nol to give ester 54 (13). 

Woolford, M.W., Williamson, J.H., Day, A.M. and Copeman, P.J. (1998), The prophylactic effect of a teat sealer on bovine mastitis during the dry period and the following lactation . New Zealand Veterinary Journal, 46, 12-19. 

Li+ is currently administered topically for the relief of HSV and, in addition, it has been demonstrated that the recurrence of HSV infection is inhibited in Li+-treated patients, indicating another potential prophylactic effect of Li+ [245]. Ointment containing 8% lithium succinate has been shown to reduce the severity and the incidence of recurrent genital HSV infection in man [246]. It has also been proposed that Li+ might be efficacious in treating HIV-infected patients, although any benefits have not yet been demonstrated [247]. While HTV is a RNA virus and as such might not be predicted to be affected by Li+, it is a retrovirus and utilizes a DNA intermediate for its replication and it uses a DNA polymerase. 

Corcoran ME, McCaughran JA Jr, Wada JA. (1978). Antiepileptic and prophylactic effects of tetrahydrocannabinols in amygdaloid kindled rats. Epilepsia. 19(1) 47-55. 

The best protection was given when schumanniofoside was administered 1 min after the venom as a dose of 80 mg/kg. Protection decreased if the time interval between giving the toxin and alkaloid was increased and when this was 1 hr no protection was afforded. Little prophylactic effect was observed if schumanniofoside was injected before the venom except in the case of only 1 min. Schumanniofoside (36) was found to have a positive oxidant activity and this was proposed as the basis of its action in oxidizing the disulphide bonds of peptides in the venom. 

An absence of retinoids can lead to inflammation and metaplastic alterations such as gingivitis, shovm by Gonzales et al. (2001). Topically applied RP provides the buccal and gingival mucosa with a sufficient amount of vitamin A. We suggest that an enrichment with vitamin A may lead to prophylactic effects (e.g., a reduction of inflammatory diseases) or a therapeutic reversal of metaplastic alterations. 

Christodoulou GN, Malharas DE, Lykouras EP, et al Possible prophylactic effect of sleep deprivation. Am J Psychiatry 135 375-376, 1978 Chrousos GP, Gold PW The concept of stress and stress system disorders overview of physical and behavioral homeostasis [published erratum appears in JAMA 268 200, 1992]. JAMA 267 1244-1252, 1992 Chuang DM Neurotransmitter receptors and phophonositide turnover. Annu Rev Pharmacol Toxicol 29 71-110, 1989... 

Theophylline has two distinct action smooth muscle relaxation (i.e. bronchodilatation) and suppression of the response of the airways to stimuli (i.e. non-bron-chodilator prophylactic effects). Bronchodilatation is mediated by inhibition of... 

There is also evidence of the prophylactic effect of antiparkinsonian drugs from a chart review study showing that they substantially prevented EPS ( 454). 

Finally, there has been considerable interest in the use of vitamin E to combat EPS, including TD, based on the oxidative-stress hypothesis. A randomized trial of 12 patients receiving supplementary vitamin E and haloperidol versus 12 receiving haloperidol alone revealed that vitamin E had no prophylactic effect on acute drug-induced EPS, nor did it interfere with the antipsychotic s therapeutic efficacy ( 455). 

Nishikawa T, Tsuda A, Tanaka M, et al. Prophylactic effect of neuroleptics in symptom-free schizophrenics. Psychopharmacology 1982 77 301-304. 

Bipolar patients treated under typical clinical conditions may have a more difficult posthospital course than has been generally appreciated. Mander ( 168), for example, reported on 2745 bipolar patients initially admitted because of an episode of mania or depression, and found that lithium did not reduce the readmission rate within 3 months of discharge. As a result, he proposed that its full prophylactic effect may not occur for 6 to 12 months after the start of treatment, and that it should be reserved for long-term prophylaxis in those who have had a number of severe episodes in a defined period of time. 

It is important to make a conceptual distinction between lithium s relative prophylactic effect for the manic and the depressive phases of a bipolar disorder and, by extension, its ability to prevent recurrent depressions in unipolar disorder. 

Further, some of the studies did not report the number of manic versus depressive relapses. One exception is Coppen et al. ( 176, 177), who reported the mean affect morbidity score of patients receiving placebo (mean SD, 0.33 0.05) or lithium (0.09 0.05) for the manic phase, as well as placebo (0.31 0.06) or lithium (0.07 0.03) for the depressive phase. Thus, this study found very similar prophylactic effects. Baastrup and associates ( 6) reported a comparable number of manic and depressed phase relapses in their bipolar patients. In 22 bipolar patients, 12 relapsed six into a manic phase, five into a depressed phase, and one into a mixed phase. By contrast, Prien et al. (182) and Cundall et al. (178) found that lithium had a greater effect in preventing the manic than the depressed phase of bipolar disorder. Overall, lithium was effective in preventing both phases of a bipolar disorder. 

Takezaki H, Hanaoka M. The use of carbamazepine (Tegretol) in the control of manic-depressive psychosis and other manic, depressive states [Japanese]. Sheishin-lgaku 1971 13 173-183. Okuma T, Kishimoto A, Inoue K, et al. Anti-manic and prophylactic effects of carbamazepine on manic-depressive psychosis. Folia Psychiatr NeurolJpn 1973 27 283-297. 

In schistosome infections of experimental animals, praziquantel is effective against adult worms and immature stages, and it has a prophylactic effect against cercarial infection. 

Thus, enhancing intercellular coupling may exert a prophylactic effect against arrhythmia if arrhythmia is due to uncoupling. However, if the coupling effect is unselective, it would probably postpone an impairing effect as discussed above for ischemia. From this theoretical point of view selective couplingenhancing effects on the previously uncoupled tissue would be desirable rather than unselective. 

The mood stabilizer lithium was developed as the first treatment for bipolar disorder. It has definitely modified the long-term outcome of bipolar disorder because it not only treats acute episodes of mania, but it is the first psychotropic drug proven to have a prophylactic effect in preventing future episodes of illness. Lithium even treats depression in bipolar patients, although it is not so clear that it is a powerful antidepressant for unipolar depression. Nevertheless, it is used to augment antidepressants for treating resistant cases of unipolar depression. 

The Depakote form of valproic acid is approved for the acute phase of bipolar disorder. It is also commonly used on a long-term basis, although its prophylactic effects have not been as well established. Valproic acid is now frequently used as a first-line treatment for bipolar disorders, as well as in combination with lithium for patients refractory to lithium monotherapy and especially for patients with rapid cycling and mixed episodes. Oral loading can lead to rapid stabilization, and plasma levels must be monitored to keep drug levels within the therapeutic range. 

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