Lithium cardiovascular effect

Outside its therapeutic range, lithium has a wide range of undesirable effects. Nervous system-related effects include tremor, difficulty walking, seizures, slurred speech, and mental confusion. In addition there can be cardiovascular effects, nausea, vomiting, and kidney damage. 

During 2004 a number of clinical trials were reported involving acute and maintenance studies of lithium, mostly either comparing new atypical antipsychotic drugs with lithium in bipolar disorder or in combined treatment studies. Of the relatively few studies of the adverse effects of lithium, most clustered in the areas of cardiovascular effects and issues regarding lithium toxicity. 

Nonspecific, benign ST-T wave electrocardiographic changes are the most common cardiovascular effects of lithium. 

Typical symptoms of lithium intoxication are summarized in Table 2 [122-127]. The clinical picture of hthium intoxication is dominated by neuromuscular and cerebral symptoms in mild cases apathy, muscle weakness, tremor, and unsteady gait are seen. In more severe cases speech disturbances, myoclonic twitching, coma and convulsion can occur. Pulse irregularities and circulatory collapse may supervene. Lithium often causes T-wave flattening or inversion on the electrocardiogram, but clinically important cardiovascular effects are rare, with sinus-node dysfunction reported most often [123]. Residual neurological sequelae consisting of cerebellar dysfunction with ataxia, neuropathy and supra-bulbar symptoms are not unusual. 

The stimulant and/or cardiovascular effects of the amfetamines have been shown to be opposed by lithium in some, but not other studies. 

Other cardiovascular effects that may be induced by lithium include bradycardia and atrioventricular block. Changes on EKG including T-wave flattening are common. These effects are usually benign and reversible, but lithium s use in patients with significant cardiovascular disease should be with caution. 

CCAs (channel blockers influx inhibitors) have been used primarily for the treatment of cardiovascular disorders (e.g., supraventricular arrhythmias, angina, and hypertension). Agents such as verapamil exert their effects by modulating the influx of Ca across the cell membrane, thus interfering with calcium-dependent functions. Based partly on the common effects of lithium and this class of drugs (e.g., effects on Ca "" activity), the CCAs have been studied as a potential treatment for mania. Janicak et al. (251) reported the results of a 3-week, double-blind comparison of verapamil versus placebo, which did not demonstrate a beneficial effect for verapamil (up to 480 mg/day) in 33 acutely manic hospitalized patients. 

The effects of lithium on the cardiovascular system are usually tolerated at both therapeutic and toxic plasma levels. Common changes include the following ... 

The teratogenic effects of lithium have been reviewed in several articles (466,467,488) two reviews of drug-related congenital malformation briefly mentioned lithium and cardiovascular teratogenesis (480,489). The authors concluded that while the risk of cardiovascular malformation is lower than once believed, it is nevertheless increased. 

Initial side effects are mild and include tremor, lethargy, nausea, diarrhea, and abdominal discomfort. Lithium treatment has been associated with headache symptoms described as episodes of moderately severe, throbbing occipital pain lasting 6 to 12 hours, but these headaches are easily distinguishable from the cluster headache and disappear when lithium is withdrawn. Lithium should be administered with caution to patients with significant renal or cardiovascular disease, dehydration, pregnancy, or concomitant diuretic use. 

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