Amitriptyline dosing

Mitchell and Groat (526), by contrast, found active drug therapy only marginally effective in the treatment of bulimia nervosa. This may have been due in part to the relatively low amitriptyline doses used (maximum 150 mg per day), resulting in average blood levels of only 103 ng/mL. 

In a retrospective analysis of 7 patients taking phenprocoumon and amitriptyline, unpredictable and massive fluctuations in prothrombin times (increases and decreases) were noted, which were not seen in a control group of 7 other patients not taking amitriptyline. Note that the amitriptyline dose was not stable. Anticoagulant control improved on stopping the amitriptyline in 5 of the patients. The same authors reported another similar case in a patient taMng phenprocoumon and amitriptyline. ... 

A 37-year-old woman who had been taking amitriptyline 75 mg daily, valproate and olanzapine for 3 years, developed extreme dryness of the mouth, nausea and dizziness shortly after starting to take terbinafine 250 mg daily. Serum levels of amitriptyline and its metabolite nortriptyline rose from just under 400 nanomol/L to over 1800 nanomol/L. Terbinafine was stopped, and the amitriptyline dose reduced to 25 mg daily, but the amitriptyline and nortriptyline levels did not return to baseline for several months. The patient had normal CYP2D6 metaboliser status. ... 

Note Derivatization with this reagent sequence in combination with extraction and TLC separation is speciftc for amitriptyline and nortriptyline in the analysis of plasma furthermore its high sensitivity allows its employment in pharmacokinetic studies, e. g. after the oral administration of a single dose of 25 mg amitriptyline. 

Tricyclic antidepressants (TCAs) such as amitriptyline and doxepin have been used with some success in the treatment of IBS-related pain (Table 18-5). They modulate pain principally through their effect on neurotransmitter reuptake, especially norepinephrine and serotonin. Their helpfulness in functional gastrointestinal disorders seems independent of mood-altering effects normally associated with these agents. Low-dose TCAs (e.g., amitriptyline, desipramine, or doxepin 10 to 25 mg daily) may help patients with IBS who predominantly experience diarrhea or pain. 

Amitriptyline (Elavil) 10-25 mg at bedtime with weekly increments to a target dose of 25-150 mg of amitriptyline or an equivalent dose of another TCA ... 

Compared to antipsychotics, there are even fewer studies on the prescribing patterns of antidepressants done in Asian countries. Pi etal. (1985) conducted a survey of psychotropic prescribing practices reported by psychiatrists in 29 medical schools in 9 Asian countries. Daily dose range of tricyclic antidepressants (TCAs) such as amitriptyline, imipramine, and nortriptyline in Asian countries was comparable to the practice in USA. This is despite differences found between Asian and non-Asian populations in the pharmacokinetics of TCAs (Pi et al, 1993). A questionnaire on the practical prescribing approaches in mood disorders administered to 298 Japanese psychiatrists was reported by Oshima et al. (1999). As first-line treatment, the majority of respondents chose newer TCAs or non-TCAs for moderate depression and older TCAs for severe depression. Combination of antidepressants and anxiolytics was preferred in moderate depression, while an antidepressant and antipsychotic combination was common in severe psychotic depression. Surprisingly, sulpiride was the most favored drug for dysthymia. In a naturalistic, prospective follow-up of 95 patients with major depression in Japan, the proportion of patients receiving 125 mg/day or less of imipramine was 69% at one month and 67% at six months (Furukawa et al., 2000). 

Some studies compare dietary supplements to sub-therapeutic dosages of prescription medicine. For example, St. John s wort is compared to some of the tricyclic antidepressants. However, the given doses of amitriptyline and imipramine were below the recommended antidepressant doses. 

The height of a child is 120 cm and the weight is 130 lb. The usual adult dose of Elavil (Amitriptyline HC1) is 75 mg/day. What would be the dose for the child based on body surface area ... 

Tricyclic Antidepressants (TCAs). The TCAs have been nsed to treat ADHD for 30 or more years. Most often used are imipramine (Tofranil) and desipramine (Norpramin), mainly becanse they are the TCAs that most specihcally increase norepinephrine activity. Remember, boosting norepinephrine activity in the brain shonld improve attention. Other TCAs, namely, amitriptyline (Elavil, Endep) and nortriptyline (Pamelor), have been used, though they also increase norepinephrine activity. TCAs do offer a modest benefit for both the inattention and the hyperactivity of ADHD. In addition, they are often effective at doses mnch lower than those required to treat depression. However, their effectiveness nsnally falls short of the stimulant medications. In addition, TCAs have considerable side effects including dry mouth, constipation, drowsiness, weight gain, and adverse cardiac effects. 

When treating insomnia without depression, doxepin and amitriptyline (both tricyclic antidepressants) can be administered in low doses (25-100 mg) at bedtime. These antidepressants, however, do have troublesome anticholinergic side effects (dry mouth, constipation, blurred vision, dizziness) and adverse effects on the heart, and they can be lethal if taken in overdose. Because of their effect on heart function, these antidepressants should be avoided in patients with heart problems and administered cautiously, if at all, to those who are already receiving one of any number of newer antidepressants that inhibit the metabolism of the TCAs. 

Braithwaite et al. (B20) treated fifteen patients with a fixed daily dose of 150 mg of amitriptyline by mouth for 6 weeks. Plasma amitriptyline and nortriptyline levels were measured, by GLC, in venous blood collected 19 hours ( SD 4.3 hours) after the last dose of the drug. Steady-state blood levels were achieved within 2 weeks, on average, but there were large between patient differences. 

B18. Braithwaite, R. A., and Whatley, J. A., Specific gas chromatographic determination of amitriptyline in human urine following therapeutic doses. J. Chromatogr. 49, 303-307 (1970). 

Elderly patients taking amitriptyline may be at increased risk for falls start on low doses of amitriptyline and observe closely. 

Serotonin syndrome Some TCAs inhibit neuronal reuptake of serotonin and can increase synaptic serotonin levels (eg, clomipramine, amitriptyline). Either therapeutic or excessive doses of these drugs, in combination with other drugs that also increase synaptic serotonin levels (such as MAOIs), can cause a serotonin syndrome consisting of tremor, agitation, delirium, rigidity, myoclonus, hyperthermia, and obtundation. 

Dose Initial 0.25 mg PO tid, wkly 10.25 mg/dose, to 3 mg max max 4 mg for RLS Caution [C, /-] Sev e CV, renal, or hepatic impair Contra Component allergy Disp Tabs SE Syncope, postural X BP, NA, HA, somnolence, dosed-related hallucinations, dyskinesias, dizziness Interactions t Risk of bleeding W/ ASA, NSAIDs, fevCTfew, garlic, ginger, horse chestnut, red clover, EtOH, tobacco t effects OF amitriptyline, Li, MTX, theophylline, warfarin t risk of photosensitivity W/ dong quai— use sunscreen, St. John s wort X effects W/ antacids, rifampin X effects OF ACEIs, diuretics EMS t Bleeding risk w/ concurrent EtOH, tobacco, ASA, and NSAID use t effects of warfarin OD May cause N/V, drowsiness, hypotension, and CP symptomatic and supportive... 

Amitriptyline Mixed 19 4—5 days Careful dose increase. Elderly can man-... 

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