Thioridazine , dosing

Retinitis pigmentosa can result from thioridazine doses greater than 800 mg daily (the recommended maximum dose) and can cause permanent visual impairment or blindness. 

Thioridazine poses a potentially greater danger to the eyes than CPZ. At doses greater than 800 mg/day, a retinitis pigmentosa may appear, leading to substantial visual impairment or even blindness. In some cases, the condition does not fully remit when the drug is stopped therefore, thioridazine doses of more than 800 mg/day are never recommended to allow for a reasonable margin of safety (499). 

Because of cataract development and lenticular changes in animals, baseline and periodic eye exams are recommended in the product labeling for patients receiving quetiapine. However, clinical experience with quetiapine since marketing has not supported a significant risk of cataracts. Retinitis pigmentosa can result from use of thioridazine doses greater than 800 mg daily. It is caused by melanin deposits, and can result in permanent visual impairment or blindness. There is no evidence that it is a function of cumulative dose. ... 

Thioridazine (Mellaril). The potency and effects of thioridazine are very similar to chlorpromazine. It should also be started at a relatively low dose and increased stepwise to help patients become adjusted to its effects. 

Several studies have evaluated the use of low doses of the typical antipsychotics. These include studies of high potency antipsychotics such as haloperidol, medium potency antipsychotics such as loxapine, and low potency antipsychotics such as chlorpromazine and thioridazine. In general, the studies have shown that antipsychotics reduce impulsivity and protect from psychotic decompensation. 

Tardive dyskinesia can occur in manic patients on neuroleptics alone, the frequency may be greater than in schizophrenics who are more likely to be on continuous medication. One possible explanation for this lies in the fact that neuroleptics are often administered to manic patients for short periods only, sufficient to abort the active episode, and then abruptly stopped. Thus high doses of neuroleptics are separated by drug-free periods, leading to a situation most likely to precipitate tardive dyskinesia. The recent increase in prescribing high potency neuroleptics such as haloperidol instead of low potency drugs such as chlorpromazine or thioridazine has undoubtedly increased the frequency of tardive dyskinesia. Clearly, use of the atypical antipsychotics with the very low frequency of EPS makes them the treatments of choice. 

Ziprasidone, pimozide, mesoridazine, and thioridazine have been shown to prolong the QT interval, and drugs with this potential have been associated with torsade de pointes-type arrhythmias and sudden death. Perform a baseline ECG and measure serum potassium and magnesium before initiation of treatment and periodically during treatment, especially during a period of dose adjustment. Patients with QT interval over 450 msec should not receive mesoridazine or thioridazine. Avoid ziprasidone in patients with histories of significant cardiovascular illness (eg. 

Zaleplon (Sonata) [C IV] [Sedotive/Hypnotic] Uses Insomnia Action A nonbenzodiazepine sedative/hypnotic, a pyrazolopyrimidine Dose 5-20 mg hs PRN -1- w/ renal/hepatic insuff, elderly Caution [C, /-] w/ mental/ psychological conditions Contra Component allergy Disp Caps SE HA, edema, amnesia, somnolence, photosens Interactions t CNS depression W/ CNS d es-sants, imipramine, thioridazine, EtOH X effects W/ carbamazepine, phenobarbital, phenytoin, rifampin EMS Concurrent EtOH can t adverse CNS effects OD May cause profound CNS depression symptomatic and supportive Zanamivir (Relenza) [Antiviral/Neuramidase Inhibitor] Uses Influenza A (including HlNl swine flu) B Action X Viral neuraminidase Dose Adults Feds > 7 y.2 inhal (10 mg) bid for 5 d initiate w/in 48 h of Sxs Caution [C, M] Contra Pulm Dz Disp Powder for inhal SE Bron-chospasm, HA, GI upset EMS Does not reduce risk of transmitting virus monitor for bronchospasm or other severe resp events OD May cause resp problems s5rmptomatic and supportive... 

Opacities of the cornea and lens due to deposition of fine particulate matter are a common complication of chlorpromazine therapy but regress after drug withdrawal. The most serious ocular complication is pigmentary retinopathy associated with high-dose thioridazine administration it is an irreversible condition leading to decreased visual acuity and possibly blindness. 

Cardiovascular side effects. Ziprasidone produced a mean QTc prolongation of 21 ms at maximal blood levels achieved with typical therapeutic doses. However, in all clinical trials, the rate of QTc intervals greater than 500 ms (considered a threshold for arrhythmia risk) did not differ from the rate associated with placebo (<0.1%). The QTc effect of ziprasidone is larger than that of other atypical antipsychotics but smaller than that of thioridazine. Blood levels of ziprasidone increased about 40% when ketoconazole (a metabolic inhibitor) was coadministered, and no change in QTc duration was detected. 

Ball WA, Caroff SN Retinopathy, tardive dyskinesia, and low-dose thioridazine (letter). Am J Psychiatry 143 256-257, 1986... 

Lower potency neuroleptics, such as thioridazine and chlorpromazine, have a decreased incidence of EPS when compared with higher potency agents, such as haloperidol or fluphenazine. Novel agents, such as clozapine and quetiapine, are virtually devoid of EPS effects when given at their recommended dosing range. 

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