Drug interaction for the dental physcion.

3. Is
Drug interaction
beneficial or
harmful
?

4. Is a situation in which a substance
(usually another drug) affects the
activity of a drug when both are
administered together.
Drug interaction

5. when both drug's effect is increased.
EX: the use of codeine with paracetamol to increase its analgesic effect.
when one or both drug's effect is decreased.
EX: the combination of clavulinc acid with amoxicillin in order to
overcome bacterial resistance to the antibiotic.
Synergistic
Antagonistic
1+1=3
drug interaction
EX: the combination of bacteriostatic antibiotic with bactericidal
one.
1+1=<2

6. Minor Minimally clinically significant.
Minimize risk; assess risk and consider
an alternative drug.
Drug Antagonistic Interaction Classification
Major High clinical significant. Avoid
combinations; the risk of the interaction
outweighs the benefit.
Moderate Moderately clinically significant. Usually
avoid combinations; use it only under
special circumstances.

7. Outside body
Absorption
Distribution
Metabolism[biotransformation]
Excretion
Site of drug interaction

9. Outside body
Site of drug interaction
Some classic examples of this type of interaction
include that :
Thiopentone [induction of general anaesthesia ]
and Suxamethonium [muscle relaxant ]
should not be placed in the same syringe.
Penicillin and Anticoagulants.
Penicillin and Aminoglycosides.
Ciprofloxacin with furosemide*
and same is true for
*Lasix

11. Absorption
Site of drug interaction
Some drugs, such as the Laxative increase
the speed with which a substance passes
through the intestines. So they decrease the
total absorption of drugs.
Laxative Oral medications
Gastric motility.

12. Absorption
Site of drug interaction
Some drugs, such as the Atropine decreases
the speed with which a substance passes
through the intestines. So they increase the
total absorption of drugs.
Atropine* Oral medications
*Digestant - antispasmodic
Gastric motility.

13. Absorption
Site of drug interaction
So they increase the total absorption of the
drug.
Sorbitol* paracetamol
*Sweetener
Absorption rate.

14. Absorption
Site of drug interaction
Certain drugs require an acidic media for absorption. Others
require the alkaline media of the intestines. Any
modification in the pH could change this absorption.
In the case of use of antacids, an increase in pH which can
inhibit the absorption of mentioned drugs.
In this case a gap of two to four hours between taking the
two drugs is usually sufficient to avoid the interaction.
Antacids
•Sulfonamides
•Anticoagulants
pH of environment.

15. Absorption
Site of drug interaction
The presence of di- or trivalent cations can cause
the chelation of certain drugs, making them
harder to absorb. This interaction frequently
occurs between drugs such as tetracycline or
the fluoroquinolones and dairy products.
•Tetracyclines
•Fluoroquinolones*
•Antacids.
•Ca++
Tarivid- ciprobay – ciprofloxacin – ofloxacin -
Chelation.

16. Combining these medications may increase your risk of
developing gastrointestinal ulcers and bleeding. You may
need a dose adjustment or more frequent monitoring by
your doctor to safely use both medications.
Absorption
Site of drug interaction
Salicylates
[aspirin] Diclofenac*↔
Voltaren – olfen – rheumafen – dolphin - cataflam
Side effects.

18. Competition with plasma protein.
Distribution
Site of drug interaction
Competition with receptor.
Non Competitive block

19. Distribution
Site of drug interaction
Transport and distribution interactions
The main interaction mechanism is competition for
plasma protein transport. In these cases the drug that
arrives first binds with the plasma protein, leaving the
other drug dissolved in the plasma, which modifies its
concentration.
Competition with plasma protein.

20. Distribution
Site of drug interaction
The main interaction mechanism is competition for
plasma protein transport. In these cases the drug with
higher binding affinity with the plasma protein, displace
the other drug dissolved in the plasma, which modifies its
toxic effect.
•Salicylates
•Sulfonamides
Methotrexate*↔
*methotrexate
chemotherapy agent and immune system suppressant.
Competition with plasma protein.

21. Site of drug interaction
Competition with receptor.
Distribution
Non Competitive block

22. Competition with
receptor.
Non Competitive block
1
2
1
1
Normal.
Competition with receptor.
Antihypertensive Antidepressant

23. •Atenolol*
Possible severe, prolonged hypertension
or cardiac arrhythmia due to epinephrine
component.
Site of drug interaction
Levonordefrin, Epinephrine or Norepinephrine
Vasopressor [L.A.]
Competition with receptor.
* Antihypertention
Distribution

24. epinephrineErgot alkaloid
Severe, persistent hypertension or
cerebrovascular accidents (e.g., rupture of
cerebral blood vessel) .
Site of drug interaction
Competition with receptor.

25. epinephrine
•MAO inhibitors*
•Antidepressants [tricyclic].
Site of drug interaction
Possible severe, prolonged hypertension
or cardiac arrhythmia due to epinephrine
component.
*Antidepressant
Non Competitive block

26.  Anxiety disorders,
Eating disorders,
Chronic pain, neuropathic pain,
Snoring,
Sleep disorders,
Migraine,
Addiction, dependence.
Antidepressants
The most important classes of antidepressants are the
Selective serotonin inhibitors,
tricyclic antidepressants (TCAs),
monoamine oxidase inhibitors (MAOIs).
are drugs used for the treatment of major depressive
disorder and other conditions, including:

27. The use of live, attenuated cholera vaccine with systemic antibiotics may result
in a diminished immunologic response to the vaccine. Some antibiotics may be
active against the vaccine strain of Vibrio cholerae, thereby preventing a
sufficient degree of multiplication to occur in order to induce a protective
immune response.
MANAGEMENT: Live, attenuated cholera vaccine should not be
administered during or for at least 14 days after treatment with
systemic antibiotics.
cholera vaccine.antibiotics ↔
Mechanism of action.
Distribution
Site of drug interaction

28. clindamycin erythromycin
Clindamycin, Erythrocin (erythromycin)
Lincomycin have antagonistic effects. The mechanism is
competitive binding of the 50S ribosomal subunit.
Site of drug interaction
MANAGEMENT: Clindamycin or lincomycin should not be used concurrently
with erythromycin.
Mechanism of action.
Distribution

29. data indicate antagonism. When these drugs are
given together, neither has predictable therapeutic
efficacy.
Data are available for erythromycin, although this
interaction could occur with any macrolide.
Site of drug interaction
Erythromycin amoxicillin
Mechanism of action.
Distribution

30. Metabolism
[biotransformation]

31. The simultaneous administration of drugs that induce microsomal
liver enzymes, such as phenytoin or phenobarbital, may
accelerate the elimination of metronidazole, resulting in reduced
plasma levels; impaired clearance of phenytoin has also been
reported.
Drugs that Inhibit microsomal liver Enzymes
The simultaneous administration of drugs that decrease
microsomal liver enzyme activity, such as cimetidine*, may
prolong the half-life and decrease plasma clearance of
metronidazole.
Drugs that Induce microsomal liver Enzymes
Site of drug interaction
Metabolism[biotransformation]
*Tagamet

32. has been reported to potentiate the
anticoagulant effect of warfarin and other
anticoagulants, resulting in a prolongation
of prothrombin time.
Site of drug interaction
Metabolism[biotransformation]
Anticoagulants Metronidazole
Inhibit microsomal liver Enzymes

33. amoxicillin, increases the blood levels and effects of
methotrexate.
increased side effects such as nausea, vomiting, mouth ulcers,
and low blood cell counts, which can make you more likely to
develop anemia, bleeding problems, and infections.
Metabolism[biotransformation]
Site of drug interaction
Amoxicillin*methotrexate ↔
*Inhibit microsomal liver Enzymes

34. Dangerous hypoglycemia resulted
Metabolism[biotransformation]
Site of drug interaction
Diamol**Salicylates* ↔
**Hypoglycaemic
*Inhibit microsomal liver Enzymes

35. Pethidine metabolism inhibited resulted in Toxic
maifestation from pethidine
Metabolism[biotransformation]
Site of drug interaction
Oral contraceptives**Pethidine* ↔
*Analgesic
*Inhibit microsomal liver Enzymes

37. Combining these medications may increase the risk of
kidney and/or nerve damage.
if you experience signs and symptoms that may suggest
kidney damage such as nausea, vomiting, loss of appetite,
increased or decreased urination, sudden weight gain or
weight loss, fluid retention, swelling, shortness of breath,
muscle cramps, tiredness, weakness, dizziness, confusion,
and irregular heart rhythm.
dehydration can also harm the kidney.
Excretion
Site of drug interaction
gentamicin ↔ clindamycin

38. Excretion
Site of drug interaction
Indomethacin*
*Non steroidal anti-inflammatory
Moduretic**↔
**Diuretic
Indomethacin causes elevations of serum creatinine
and moduretic prevents re-absorption of sodium
The result of combination is acute renal failure.

39. Iodinated contrastAminoglycosides ↔
Excretion
Site of drug interaction
Enhanced nephro-toxicity that resulted in
acute renal failure