Protriptyline dosing

TCAs Once-a-day dosing may be prescribed for maintenance therapy. When the nurse administers the total daily dosage at night, the sedative effects promote sleep, and the adverse reactions appear less troublesome Because protriptyline may produce a mild stimulation in some patients, it is usually not given as a single bedtime dose... 

Tricyclic Antidepressants (TCAs). TCAs were introduced in the 1950s and over the years have become the mainstay of treatment for cataplexy and the other REM-related symptoms. The doses used are usually less than the doses required in the treatment of depression. Imipramine (Tofranil) is the most widely used TCA for narcolepsy and is usually effective at doses from 10 to 75 mg given once a day. Some doctors prefer the TCA protriptyline (Vivactil) because it has mild stimulant effects, but it has not been as widely used or as thoroughly studied in narcolepsy. The common side effects of TCAs are drowsiness, dry mouth, and constipation, but these are usually not a problem at the lower doses used for narcolepsy. Patients should receive a baseline electrocardiograph (EKG) before starting a TCA and should have blood levels of the medication checked periodically. 

After checking a baseline EKG to rule out undetected heart rhythm abnormalities, many clinicians use a low dose of imipramine or protriptyline to treat the auxiliary symptoms of narcolepsy. Either of these can be started at 10 mg taken once a day and then slowly increased over several weeks as needed until the symptoms... 

Cardiovascular disorders Use with extreme caution in patients with cardiovascular disorders because of the possibility of conduction defects, arrhythmias, CHF, sinus tachycardia. Ml, strokes, and tachycardia. These patients require cardiac surveillance at all dose levels of the drug. In high doses, TCAs may produce arrhythmias, sinus tachycardia, conduction defects, and prolonged conduction time. Tachycardia and postural hypotension may occur more frequently with protriptyline. Hyperthyroid patients Hyperthyroid patients or those receiving thyroid medication require close supervision because of the possibility of cardiovascular toxicity, including arrhythmias. 

Nortriptyline therapy should be initiated at 25 mg/day, and the dose should be increased to 75 mg/day over 1-2 weeks depending on tolerability and clinical response. Some patients require doses of up to 150 mg/day. Amoxapine therapy should be started at 50 mg/ day, and the dose should be titrated to 400 mg/day amoxapine has a short half-life and should be given in divided doses. Treatment with protriptyline can be started at 10 mg/day, and the dose can be increased to up to 60 mg/day. Maprotiline therapy should be started at 50 mg/day, and that dose should be maintained for 2 weeks the risk of seizure is increased if the dose is raised too quickly. The dose can be increased over 4 weeks to 225 mg/day. 

This tricyclic drug is superior to placebo and equivalent to standard HCAs in outpatient populations. It is a more potent agent on a per milligram basis (i.e., average daily dose is 20 to 60 mg), partly because of its low first-pass effect and long half-life ( Table 7-5). Flence, patients develop substantially higher plasma levels per milligram dose of protriptyline versus other TCAs. 

FIGURE 7-47. Heroic combo 3 High-dose venlafaxine plus NRI. Here, 5HT is single-boosted, NE is double-boosted, and DA may be single-boosted. The NRI could be either selective reboxetine or a nonselective TCA such as desipramine, maprotilene, nortriptyline, or protriptyline. 

Be aware that among this class of agents (tri cy cl I c/tet racy cl ic antidepressants), protriptyline has uniquely low dosing (15-40 mg/day for profripfyline compared to 75-300 mg/day for mosf ofher tri cy cl I c/tet racy cl I c antidepressants)... 

With the exception of protriptyline, the half-lives are approximately 24 h for the monomethylated TCAs allowing for single daily dosing, nsually at bedtime. 

The antihypertensive effects of guanethidine are reduced or abolished by amitriptyline, desipramine, imipramine, nortriptyline and protriptyline. Doxepin in doses of300 mg or more daily interacts similarly, but in smaller doses appears not to do so, although one case is reported with doxepin 100 mg daily. A few case reports surest that maprotiline and mianserin do not interact with guanethidine. 

The same interaction has been described in other reports, with guanethidine and desipramine, imipramine, amitriptyline, protriptyline or nortriptyline. The interaction may take seveid days to develop fully and can last an average of 5 days after discontinuation of the tricyclic. Some studies, and clinical experience suggests that doxepin does not begin to interact until doses of about 200 to 250 mg daily are used, then at 300 mg or more daily it interacts to the same extent as other tricyclics. " However, in one case excessive hypertension occurred in a man taking guanethidine and doxepin 100 mg daily. ... 

---