Tricyclic antidepressants monitoring

Tricyclic antidepressants Monitor for change in vision, sedation, dry mouth, gastrointestinal upset, and orthostatic dizziness. 

Antidepressants are used in neuropathic pain and migraine prophylaxis. Tricyclics require monitoring of plasma drug concentrations to achieve optimal effect... 

Rao, M.L. et al. 1994. Monitoring tricyclic antidepressant concentrations in serum by fluorescence polarization immunoassay compared with gas chromatography and HPLC. Clin Chem. 40 929. 

Tricyclic antidepressants Despite the numerous publications over the past 30 years on the determination of the TCAs (Tricyclic Antidepressants) by HPLC to establish possible therapeutic windows, both therapeutic drug monitoring and pharmacokinetic calculations have revealed there is considerable variation (10- to 50-fold) in plasma concentrations between individuals with these drugs. The plasma concentrations are usually in the range of 50-300 ng/ml. 

Drug interactions Serious and/or life-threatening drug interactions could occur between amprenavir and amiodarone, lidocaine (systemic), tricyclic antidepressants, and quinidine. Concentration monitoring of these agents is recommended if these agents are used concomitantly with amprenavir. 

Preskorn SH, Lane RM (1995) Sertraline 50 mg daily the optimal dose in the treatment of depression. IntClin Psychopharmacol 10 129-141 Preskorn SH, Dorey RC, Jerkovich GS (1988) Therapeutic drug monitoring of tricyclic antidepressants. Clin Chem 34 822-828... 

Preskorn, S.H., Weller, E., Hughes, C., and Weller, R. (1986) Plasma monitoring of tricyclic antidepressants defining the therapeutic range for imipramine in depressed children. Clin Neuropharma-col 9 265-267. 

Hollister LE Monitoring tricyclic antidepressant plasma concentrations. JAMA 241 2530-2533, 1979... 

Goldberg RJ, Capone RJ, Hunt JD Cardiac complications following tricyclic antidepressant overdose issues for monitoring policy. JAMA 254 1772-1775, 1985... 

Preskorn SH. Tricyclic antidepressants the whys and hows of therapeutic drug monitoring. J Clin Psychiatry 1989 50(suppl 7) 34-42. 

Preskorn SH, Jerkovich GS. Central nervous system toxicity of tricyclic antidepressants phenomenology, course, risk factors and role of therapeutic drug monitoring. J Clin Psychopharmacol 1990 10 88-95. 

The use of drug plasma levels to effect optimal clinical response and to minimize adverse or toxic effects is standard practice in general medicine (e.g., phenytoin, digoxin), as well as in psychiatry (e.g., lithium, tricyclic antidepressants, valproate see Chapter 3). The theoretical basis for plasma level monitoring rests on several factors, including ... 

Preskorn SH. Therapeutic drug monitoring of tricyclic antidepressants a means of avoiding toxicity. Psychopharmacol Bull 1989 7 237-243. 

Nortriptyline and desipramine may be the tricyclic antidepressants (TCAs) of choice, given their extensive assessment during pregnancy and well-known therapeutic concentrations, which should be monitored. 

Plasma levels of doxepin similar to those achieved during oral therapy may be obtained with topical application the usual drug interactions associated with tricyclic antidepressants may occur. Therefore, monoamine oxidase inhibitors must be discontinued at least 2 weeks prior to the initiation of doxepin cream. Topical application of the cream should be performed four times daily for up to 8 days of therapy. The safety and efficacy of chronic dosing has not been established. Adverse local effects include marked burning and stinging of the treatment site which may necessitate discontinuation of the cream in some patients. Allergic contact dermatitis appears to be frequent, and patients should be monitored for symptoms of hypersensitivity. 

FIGURE 6-16. If a tricyclic antidepressant (TCA) is given together with a serotonin selective reuptake inhibitor (SSRI), the SSRI will prevent TCA metabolism. This causes TCA levels to increase, which can be toxic. Therefore either monitoring of TCA plasma concentration with dose reduction of the TCA, or avoidance of the combination, is required. 

Mitchell PB (2004) Therapeutic drug monitoring of non-tricyclic antidepressant drugs. Clin Chem Lab Med 42 1212-1218... 

Hackett LP, Dusci LJ, Ilett KF (1998) A comparison of high-performance liquid chromatography and fluorescence polarization immunoassay for therapeutic drug monitoring of tricyclic antidepressants. Ther Drug Monit 20 30-34... 

Precautions The tricyclic antidepressants should be used with caution in manic-depressive patients, since they may unmask manic behavior. The tricyclic antidepressants have a narrow therapeutic index for example, 5 to 6 times the maximal daily dose of imipramine can be lethal. Depressed patients who are suicidal should be given only limited quantities of these drugs and should be monitored closely. Drug interactions with the tricyclic antidepressants are shown in Figure 12.5. 

Tricyclic antidepressants commonly produce abnormalities in cardiovascular function in children and adults, and there are reports of cardiac arrest and death in children. Cardiovascular function should be carefully monitored in children taking these drugs (Dulcan, 1994). 

An important practical question concerns the compatibility of tricyclic antidepressants and electroconvulsive therapy (ECT). This has been studied in 15 patients taking 150-250 mg/day of imipramine or amitriptyline who received 4-16 ECT treatments (11). Continuous monitoring of cardiac function by oscilloscopy showed dysrhythmias in 40% of the ECT sessions. There were single extra... 

Sudden death, possibly related to cardiac effects in children and adolescents, has been discussed (SEDA-15, 13 SEDA-16, 9 SEDA-18, 18) it was concluded that children taking tricyclic antidepressants require careful monitoring of the electrocardiogram, even when relatively low doses are used (SEDA-18,18). 

---