Conventional drug therapy involves rapid and complete release of the drug immediately after administration, which leads to fluctuating blood levels and risks of overmedication or undermedication. Sustained-release drug therapy slowly releases the drug over an extended period of time, maintaining more constant blood levels and minimizing risks. This therapy reduces dosing frequency, improves patient compliance, and provides more reliable treatment of chronic diseases. However, sustained-release drugs may have higher costs and less flexibility than conventional drugs.

1. Comparison between conventional and sustained-release
drugs
Conventional Drug Therapy
1. Rapid and complete release of drug
immediately after administration.
2. Absorption is the rate-limiting step
(kr >>> ka).
3. Blood level fluctuates (Peak and
Valley).
4. There is risk of overmedication or
under medication at periods of
time.
5. Frequent dosing.
6. Patient non compliance. Therapeutic
inefficiency / failure.
7. Inconvenience of patient.
Sustained-Release Drug Therapy
1. Slow/controlled release of drug over an
extended period of time.
2. Drug release from the dosage form is the
rate-limiting step (ka >>> kr ).
3. Constant blood level is maintained over a
prolonged period (Reduced fluctuation).
4. Reliable therapy as the risk is minimized.
5. Reduced frequency of dosing.
6. Improved patient compliance.
7. Enhanced patient convenience with day-
time and night-time medication.

2. 8. No therapeutic action during
overnight no dose period.
9. Risk of symptom breakthrough.
10. Incidence and severity of
untoward effects related to high -
peak plasma concentration .
11. More total dose over the entire
course of therapy.
12. More side effects.
13. Health care cost .
14. Permits prompt testing of
therapy.
15. Incidence of severity of GI side
effects due to dose dumping of
irritant drugs .
16. More flexibility for physician in
adjusting dosage required.
8. Maintains therapeutic action during
overnight no dose period.
9. Improved treatment of many chronic
diseases (minimizing symptom
breakthrough).
10. Incidence and severity of untoward
effects related to high – peak plasma
concentration .
11. Less total dose over the entire course
of therapy.
12. Minimize/eliminate incidence of
local/systemic side effects.
13. Health care cost .
14. Does not prompt.
15. Incidence of severity of GI side effects
due to dose dumping of irritant drugs .
16. Less flexibility.

3. 17. Can accommodate abnormal
cases of disease safety offering
drug disposition etc.
18.  Chance of at any site of GIT
(local irritation ).
19. No problems for drugs with too
short half lives.
20. Per unit cost is less. 
21.
17. Can not accommodate.
18.  Chance of at any site of GIT (local
irritation).
19. Not suitable for drugs with too short
half lives, drugs needing specific
requirements for absorption from GIT.
20. Per unit cost is more. 
21.
Time
Time