Overdose of Amitriptyline

Description

Data on overdoses of the drug amitriptyline. Amitriptyline is a drug prescribed by physicians as an antidepressant. However, there are also conjectured side effects that seem to be related to the use of the drug: irregular heart beat, abnormal blood pressure and irregular waves on the electrocardiogram (ECG). This dataset (originally from Rudorfer, 1982) gives data on 17 patients admitted to hospital after an overdose of amitriptyline. The two response variables are: TCAD and AMI. The other variables are predictors.

Usage

data("Overdose")

Format

A data frame with 17 observations on the following 7 variables.

TCAD

total TCAD plasma level, a numeric vector

AMI

amount of amitriptyline present in the TCAD plasma level, a numeric vector

Gender

a factor with levels Male Female

amount

amount of drug taken at time of overdose, a numeric vector

BP

diastolic blood pressure, a numeric vector

ECG_PR

ECG PR wave measurement, a numeric vector

ECG_QRS

ECG QRS wave measurement, a numeric vector

Source

Johnson & Wichern (2005), Applied Multivariate Statistical Analysis, Exercise 7.25, p. 426.

References

Rudorfer, M. V. Cardiovascular changes and plasma drug levels after amitriptyline overdose. (1982). J. Toxicology - Clinical Toxicology. 19(1),67-78. doi:10.3109/15563658208990367, PMID: 7154142.

Clay Ford, "Getting started with Multivariate Multiple Regression", https://library.virginia.edu/data/articles/getting-started-with-multivariate-multiple-regression.

ECG measurements:

PR

https://en.wikipedia.org/wiki/PR_interval

QRS

https://en.wikipedia.org/wiki/QRS_complex

Examples

data(Overdose)
str(Overdose)
pairs(Overdose) 

over.mlm <- lm(cbind(TCAD, AMI) ~ Gender + amount + BP + ECG_PR + ECG_QRS, data = Overdose)
coef(over.mlm)

# check for outliers
cqplot(over.mlm)

# HE plot shows that relations of responses to predictors are essentially one-dimensional
heplot(over.mlm)

# canonical correlation analysis 
if(require(candisc)) {
cancor(cbind(TCAD, AMI) ~ as.numeric(Gender) + amount + BP + ECG_PR + ECG_QRS, data = Overdose)
}