Drugs in the Body (1)

Recurrence Relations

A patient is given an initial dose of 50mg of a drug. Each hour the patient is given a 20mg tablet of the drug.

The drug has a decay factor of 70% ie. every 20 minutes ,

70% of the drug remains in the body.

Set up a recurrence relation and use itto determine the long term state of the drug in the body.

Drugs in the Body

Drugs in the Body

A patient is given an initial dose of 80mg of a drug. This drug is given in tablet form as 30mg tablets every hour.

The drug has a decay factor of 85% ie. every 15 minutes , 85% of the drug present in the body at the start

of the 15 minute interval remains in the body. Set up a recurrence relation and use

it to determine the long term state of the drug in the body.

Drugs in the Body

Initial dose : 120mgTablet : 40 mg tablet given every hour.

Decay factor : The drug has a decay factor of 68% ie. every 30 minutes ,

68% of the drug present in the body at the start of the 30 minute interval remains in the body.

Set up a recurrence relation and use it to determine the long term state of the drug in the body.

Solutions

Drugs in the Body (1)

Q1. An+1=0.343An + 20, A0 = 50 Limit: L = 30.44 grams

Q2. An+1=0.522An + 30, A0 = 80 Limit: L = 62.76 grams

Q3. An+1=0.4624An + 40, A0 = 120 Limit: L = 74.4 grams