Imipramine dosing

SSRIs sometimes cause an initial jitteriness similar to that noted with initial imipramine therapy for PD. This may be more common with SSRIs than with other currently available non-TCA antidepressant therapies for PD. Just as low initial imipramine doses avert this reaction, initiating SSRI therapies with one fourth to one half the usual starting antidepressant dose followed by gradual increments with low doses can avert this reaction. This syndrome can also be blocked by add-on, low-dose, as-needed BZD therapy (e.g., alprazolam or lorazepam). 

CYP2D6 /3 blockers, antidepressants, antipsychotics, codeine, debrisoquine, dextromethorphan, encainide, flecainide, fluoxetine, guanoxan, N-propylajmaline, perhexUine, phenacetin, phenformin, propafenone, sparteine Tardive dyskinesia from antipsychotics, narcotic side effects, codeine efficacy, imipramine dose requirement, /3 blocker effect... 

The reduction in the serum levels of amitriptyline, desipramine, doxepin, imipramine and nortriptyline caused by the interaction with carbamazepine appears to be established but the clinical importance is very much less certain. Evidence from one study, that achieved a beneficial response in patients taking tricyclics and carbamazepine suggests that it is possibly not necessary to increase the tricyclic dosage to accommodate this interaction. The fact that a retrospective study found that increased imipramine doses were being given to those taking carbamazepine suggests that this interaction will be naturally accounted for. If carbamazepine is added to treatment with any of these tricyclics, be aware that the dose of the tricyclic may need to be titrated up to achieve the desired therapeutic response. Remember too that the tricyclics can lower the convulsive threshold and should therefore be used with caution in patients with epilepsy. 

Crowley, T.J. Dose-dependent facilitation or suppression of rat fighting by methamphetamine, phenobarbital, or imipramine. Psychopharmacologia 27 213-222, 1972. 

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 idea that indole hallucinogens might increase startle by interacting with presynaptic autoreceptors has received some experimental support. Davis and Sheard (49) found that lesions of the dorsal and median raphe nuclei blocked the usual excitatory effect of a low dose (40 jtg/kg) of LSD on acoustic startle. Moreover, other treatments that decreased raphe cell firing rates also blocked the excitatory effects of LSD on startle. For example, pretreatment with chlor-imipramine (CIMI), which decreases raphe cell firing indirectly by blocking 5-HT reuptake (153), blocked the usual excitatory effect of LSD on startle without preventing the entry of LSD into the brain (47). These data were consistent with the disinhibition hypothesis. 

Some phenothiazine derivatives (tranquilizers) can be hallucinogenic at high doses (e.g., imipramine (Tofranil) at oral dose of about 1 g and Ethopropazine (Parsidol) at 100 mg). 

Drew R, Siddik Z, Mimnaugh EG, Gram TE (1981) Species and dose differences in the accumulation of imipramine by mammalian lungs. Drug Metab Dispos 9 322-326. 

Tricyclic Antidepressants (TCAs). The TCAs, particularly imipramine (Tofranil), were also discovered soon after their introduction to be effective in the treatment of panic attacks. Imipramine, the best-studied TCA in the treatment of panic disorder, is most often helpful at daily doses of 150-250 mg, though it must be started at 10-25 mg, usually at bedtime, and gradually increased over 2-4 weeks. Although they are not as well studied, many clinicians prefer to use the secondary amine TCAs, desipramine (Norpramin) and nortriptyline (Pamelor), because they have milder side effects than imipramine. Clomipramine (Anafranil), though probably the TCA with the greatest side effect burden, is often said to be most effective in patients with refractory disease. 

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. 

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... 

This occurs all too frequently with the TCAs and can be life threatening. Death has been reported with doses of 2000 mg of imipramine, or the equivalent quantity of other TCAs, which approximates to 10 daily doses or less Severe intoxication has been reported at doses of 1000 mg. Because of... 

Imipramine (Tofranil) [Antidepressant/TCA] WARNING Close observation for suicidal thinking or unusual changes in behavior Uses Depres-sion, enuresis, panic attack, chronic pain Action TCA t CNS synaptic serotonin or norepinephrine Dose Adults. Hospitalized Initial 100 mg/24 h PO in doses T over several wk 300 mg/d max Output Maint 50-150 mg PO hs, 300 mg/24 h max Peds. Antidepressant 1.5-5 mg/kg/24 h daUy-qid Enuresis >6 y 10-25 mg PO qhs T by 10-25 mg at 1-2-wk int vals (max 50 mg for 6-12 y, 75 mg for >12 y) Rx for 2-3 mo, then tap Caution [D, /-] Contra Use w/ MAOIs, NAG, acute recovery from MI, PRG, CHF, angina, CVD, arrhythmias Disp Tabs, caps SE CV Sxs, dizziness, xerostomia, discolored urine Interactions t Effects W/ amiodarone, anticholinergics, BBs, cimetidine, diltiazem, Li, OCPs, quinidine, phenothiazines, ritonavir, verapamil, EtOH, evening primrose oil t effects OF CNS depressants, hypoglycemics, warfarin T risk of serotonin synd W/MAOIs 4-... 

Mannitol (OsmitroL others) [Osmotic Diuretic] Uses Cerebral edema, T lOP/ICP, renal impair, poisonings Action Osmotic diuretic Dose Test dose 0.2 g/kg/dose IV over 3-5 min if no diuresis w/in 2 h, D/C Oliguria 50-100 g IV over 90 min T lOP 0.5-2 g/kg IV over 30 min Cerebral edema 0.25-1.5 g/kg/dose IV >30 min Caution [C, ] w/ CHF or volume overload Contra Anuria, dehydration, HE, PE Disp Inj SE May exacerbate CHF, N/V/D Interactions t Effects OF cardiac glycosides X effects OF barbiturates, imipramine, Li, salicylates EMS Monitor ECG for hypo-/hyperkalemia (T wave changes) OD May cause dehydration, t urine frequency/amount hypotension and CV collapse symptomatic and supportive... 

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... 

Petti, T.A. and Law, W, 3rd. (1981) Abrupt cessation of high-dose imipramine treatment in children./AMA. 246 768-769. 

A multicenter trial comparing more appropriate doses of imipramine (75 mg twice daily, N = 167) and St. John s wort extract (250 mg twice daily standardized to 0.2% hypericin, N = 157) showed no difference in efficacy after 6 weeks of treatment. However, St. John s wort seemed to reduce anxiety symptoms more often than imipramine and was better tolerated (Woelk, 2000). A study including 240 participants compared St. John s wort with fluoxetine in mild to moderate depression and also concluded that efficacy of both treatments was comparable (Schrader, 2000). These results have been replicated in a smaller trial us-... 

Although there are continuation and maintenance guidelines for the use of antidepressants for unipolar depression, it is not clear how long a patient with bipolar depression should be treated with these medications. Rates of recurrence of bipolar depression of approximately 60% have been observed in patients taking adequate doses of lithium, alone or in combination with imipramine (APA, 1994b). As the TCAs have not been shown to be efficacious for youth with... 

There have been three randomized clinical trials and multiple case reports and open-label trials with the tricyclic antidepressants (TCAs) in PTSD, although only one study of childhood PTSD (Southwick et al., 1994) has been reported. Robert et al. (1999) reported the use of low-dose imipramine (1 mg/kg) to treat symptoms of ASD in children with burn injuries. In this study, 25 children ages 2 to 19 years were randomized to receive either chloral hydrate or imipramine for 7 days. Ten of 12 subjects receiving imipramine experienced from half to full remission of ASD symptoms, whereas 5 of 13 subjects responded to chloral hydrate. Sleep-related flashbacks and insomnia appeared to be particularly responsive to treatment. 

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