Posted by sam123 on August 31, 2007, at 14:45:59
In reply to Re: More and more warnings with new drugs » sam123, posted by Squiggles on August 31, 2007, at 14:41:09
Here is a part of a monograph for an old AP, Mellaril:
PrecautionsCaution is required in patients with narrow-angle glaucoma, prostatic hypertrophy, or ***cardiovascular disease (severe cardiovascular disease is a contraindication)**.
***Hypotension (which is usually orthostatic)** may occur, especially in females, the elderly, and in alcoholic patients. The administration of epinephrine should be avoided in the treatment of drug-induced hypotension in view of the fact that phenothiazines may induce a reverse-epinephrine effect.
As with other phenothiazines, benign repolarization changes such as prolongation of the Q-T interval, flattening of the T wave and the appearance of a U wave have been reported. These changes are usually confined to high doses and are more likely to occur when potassium blood levels are low. Like all phenothiazines, thioridazine may induce arrhythmias.
Sudden and unexplained death, apparently due to arrhythmias or cardiac arrest, has been reported. Previous brain damage or seizures may also be predisposing factors. High doses should be avoided in patients with a history of seizures.
****Convulsive seizures**** have been reported but are infrequent. However, thioridazine has been shown to be helpful in the treatment of behavioral disorders in epileptic patients. In such cases, anticonvulsant medication should be continued and dosage adjustment considered (see Drug Interactions).
Leukopenia and agranulocytosis have been reported but are infrequent. A complete blood count is recommended before the initiation of therapy, especially if long-term treatment is anticipated. Blood counts should be carried out regularly during the first few months of therapy and should be done immediately whenever clinical signs suggestive of blood dyscrasia occur.
Pigmentary retinopathy has been observed after long-term treatment, mostly in patients receiving doses exceeding the recommended maximum of 800 mg/day. Patients receiving higher doses of phenothiazines for prolonged periods should have complete eye examinations at regular intervals.
In patients with liver disease, regular monitoring of liver function is necessary.
Occupational Hazards:
Where patients are participating in activities requiring complete mental alertness (e.g. driving vehicles, operating machinery), administer the phenothiazine cautiously since impairment of reactions may occur with large doses and during early treatment.Pregnancy and Lactation:
Safe use of thioridazine in human pregnancy has not been established. Therefore, it should not be administered to pregnant women (particularly during the first trimester of pregnancy) unless the expected benefit to the patient clearly outweighs the potential risk to the fetus. Thioridazine may appear in human breast milk and therefore mothers receiving this drug should not breast-feed.Children:
Thioridazine should be kept out of the reach of children.Drug Interactions:
Phenothiazines may enhance the CNS-depressant effects of alcohol, antihistamines and other CNS depressants as well as atropine and phosphorus insecticides; the antimuscarinic effects of anticholinergic agents; and the inhibitory cardiac effects of quinidine.Use of epinephrine in the treatment of phenothiazine-induced hypotension may induce a reverse-epinephrine effect.
Phenothiazines may reduce the antiparkinsonian effects of levodopa.
Phenothiazines may ***lower the seizure threshold in epileptic patients****. Dosage adjustment of anticonvulsant medication may be necessary.
Owing to their adrenolytic action, phenothiazines may reduce the pressor effect of adrenergic vasoconstrictors.
Concurrent use with MAO inhibitors may prolong and intensify the sedative and antimuscarinic effects of phenothiazines.
Concomitant use of lithium may aggravate ****extrapyramidal symptoms**** and neurotoxicity caused by neuroleptic agents. Early signs of lithium toxicity may be masked by the antiemetic effect of phenothiazines.
poster:sam123
thread:779998
URL: http://www.dr-bob.org/babble/20070831/msgs/780005.html