Amitriptyline arrhythmia with

Tricyclic drugs have, as the name implies, a three-ring structure, and interfere with reuptake of norepinephrine and/or serotonin into axon terminals. Tricyclic drugs include imipramine (Tofranil), amitriptyline (Elavil), clomipramine (Anafranil), and nortriptyline (Pamelor, Aventil). Tricyclics have the occasional but unfortunate cardiovascular side effects of arrhythmia and postural hypotension. Newer, nontricyclic antidepressants have been developed that are collectively referred to as SSRIs. These have a potent and selective action on serotonin, and lack the cardiovascular side effects of the tricyclics. These include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), and fluvoxamine (Luvox). A fifth SSRI, citalopram (Celexa) has been used in Europe and has recently been approved in the United States. Venlafaxine (Effexor) blocks reuptake of norepinephrine and serotonin, while bupropion (Wellbutrin) acts on both dopamine and norepinephrine. 

Despite limited success with amitriptyline in some anorexia patients, using this class of antidepressants can be problematic in AN patients and therefore cannot be routinely recommended. TCAs slow gastrointestinal function and can therefore worsen the constipation and bloating that commonly plague AN patients during refeeding. In addition, TCAs can increase the likelihood of seizure or cardiac arrhythmia in patients already at risk due to electrolyte disturbances. Moreover, they are often lethal after overdose. 

PROPAFENONE I. ANTIARRHYTHMICS - disopyra-mide, procainamide 2. ANTIBIOTICS - macrolides (especially azithromycin, clarithromycin, parenteral erythromycin, telithromycin), quinolones (especially moxifloxacin), quinupristin/ dalfopristin 3. ANTICANCER AND IMMUNOMODULATING DRUGS -arsenic trioxide 4. ANTIDEPRESSANTS - TCAs, venlafaxine 5. ANTIEMETICS-dolasetron 6. ANTIFUNGALS-fluconazole, posaconazole, voriconazole 7. ANTIHISTAMINES - terfenadine, hydroxyzine, mizolastine 8. ANTI-M ALARIALS - artemether with lumefantrine, chloroquine, hydroxychloroquine, mefloquine, quinine 9. ANTIPROTOZOALS - pentamidine isetionate 10. ANTIPSYCHOTICS-atypicals, phenothiazines, pimozide II. BETA-BLOCKERS - sotalol 12. BRONCHODILATORS -parenteral bronchodilators 13. CNS STIMULANTS - atomoxetine Risk of ventricular arrhythmias, particularly torsades de pointes Additive effect these drugs prolong the Q-T interval. Also, amitriptyline, clomipramine and desipramine levels may be t by propafenone. Amitriptyline and clomipramine may t propafenone levels. Propafenone and these TCAs inhibit CYP2D6-mediated metabolism of each other Avoid co-administration... 

LEVODOPA, SELEGILINE, POSSIBLY RASAGILINE, ENTACAPONE, TOLCAPONE MAOIs Risk of adrenergic syndrome -hypertension, hyperthermia, arrhythmias - and dopaminergic effects with selegiline Levodopa and related drugs are precursors of dopamine. Levodopa is predominantly metabolized to dopamine, and a smaller proportion is converted to epinephrine and norepinephrine. Effects are due to inhibition of MAOI, which breaks down dopamine and sympathomimetics Avoid concurrent use. Onset may be 6-24 hours after ingestion. Carbidopa and benserazide, which inhibit dopa decarboxylase that converts L-dopa to dopamine, is considered to minimize this interaction. However, MAOIs should not be used in patients with Parkinson s disease on treatment with levodopa. Imipramine and amitriptyline are considered safer by some clinicians... 

Broom 2. Ginkgo biloba 3. Scopolia 4. Yohimbine 1. TCAs (e.g. amitriptyline, nortriptyline, clomipramine) 2. SSRIs (e.g. fluvoxamine fluoxetine, paroxetine) 3. Venlafaxine 4. Trazodone May develop cardiac arrhythmias and side-effects such as dryness of the mouth, retention of urine and tachycardia, t sedation Broom contains cardioactive alkalamines such as sparteine Inhibits metabolizing enzymes Anticholinergic properties (hyoscine present in scopolia may worsen side-effects of TCAs-additive antimuscarinic effects) Yohimbine alone can cause hypertension, but lower doses cause hypertension when combined with TCAs Unknown mechanism (ginkgo t sedative effects of trazodone) St John s wort inhibits the uptake of serotonin and thereby t serotonin levels Avoid concomitant use. An SSRI may be a better alternative to be used with broom... 

Figure 20). Therefore, because of its pronounced anticholinergic and potential arrhythmogenic effects, amitriptyline is contraindicated in the acute recovery phase of myocardial infarction, congestive heart failure, angina, prostatic hypertrophy, paralytic ileus, and urinary retention, and in patients undergoing surgery with general anesthetics that may cause arrhythmias (e.g., halothane) (see Table 16).

Cardiac conduction defects have been reported with nortriptyline, imipramine and amitriptyline but 2 studies (11, 12 ) have suggested less marked impairment with doxepin. The cause of these arrhythmias remains obscure although 1 study (13 ) found that urinary catecholamine levels were slightly higher in patients who developed cardiac arrhythmias compared to overdose patients who did not. This would tend to support the concept of sympathetic overactivity and the rationale for successful use of j3-adrenergic blocking drugs (13, 14 ). Another successful treatment was the reported use of 1—3 mEq/kg of sodium bicarbonate in 19 out of 20 patients with arrhythmias due to overdose (15 ). 

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