1. DRUG INTERACTIONS

2. –Adverse drug effects –Hypersensitivity –Anaphylactic reactions

3. Adverse drug effects An unwanted or harmful reaction experienced following the administration of a drug or combination of drugs under normal conditions of use and suspected to be related to the drug

4.  Onset  Severity  Type Classification

5.  Onset of event: Acute within 60 minutes Sub-acute 1 to 24 hours Latent > 2 days Classification

6.  Severity of reaction: Mild bothersome but requires no change in therapy Moderate requires change in therapy, additional treatment, hospitalization Severe disabling or life-threatening Classification - Severity

7. –Result in death –Life-threatening –Require hospitalization –Prolong hospitalization –Cause disability –Cause congenital anomalies –Require intervention to prevent permanent injury Classification - Severity

8. Type A extension of pharmacologic effect often predictable and dose dependent responsible for at least two-thirds of ADRs propranolol is given for tachycardia to reduce heart rate.It can cause heart block due to excessively slowing the heart Classification

9. Type B idiosyncratic or immunologic reactions rare and unpredictable e.g., chloramphenicol and aplastic anemia Classification

10. Type C associated with long-term use involves dose accumulation e.g., antimalarials and ocular toxicity Classification

11. Type D delayed effects (dose independent) Carcinogenicity (e.g., immunosuppressants) Teratogenicity (e.g., fetal hydantoin syndrome) Classification

12.  Types of allergic reactions Type I Type II Type III Type IV Classification- Drug Hypersensitivity

13. Understanding hypersensitivity Our immune system mediates this Immune system has lots of cells Mast cells are responsible of type 1 Antibodies cause type 11 and 111 T cells cause type 1V

14. Types of hypersensitivity reactions caused by drugs Type IImmediate, IgE- mediated Anaphylaxis, urticaria/angioede ma, bronchospasm, hypotension Type IIIgG and IgM- dependent Leukopenia, vasculitis, rashes, interstitial nephritis

15. Types of hypersensitivity reactions caused by drugs Type IIIImmune complexes with IgG and IgM Serum sickness, vasculitis, rashes, fever Type IVT cell-mediated reactions Contact sensitivity, delayed rashes

16. Examples Type 1-anaphylaxis to drugs Type 11-drug induced hemolysis Type 111-serum sickness syndrome

17. Drug-Induced Hemolytic Anemia This is where certain antibiotics can absorb to the proteins on RBC membranes Examples: penicillin, streptomycin Sometimes antibodies cause lysis and thus progressive anemia When drug is withdrawn the hemolytic anemia disappears

18. Serum sickness syndrome reaction that develops when antigen is intravenously administered resulting in formation of large amounts antigen- antibody complexes and the deposition in tissue

19. Risk factors for Drug Allergy Frequent exposure to the drug Large doses of the drug Drug given by injection rather than pill Family tendency to develop allergies and asthma.

20. Anaphylactic Reaction Life threatening Almost all anaphylactic reactions occur within 4 hours of the first dose of the drug. Most occur within 1 hour of taking the drug, and many occur within minutes or even seconds.

21. Symptoms of anaphylactic shock Skin reaction - Hives, redness/flushing, sense of warmth, itching Difficulty breathing - Chest tightness, wheezing, throat tightness Fainting - Light-headness or loss of consciousness due to drastic decrease in blood pressure ("shock") Rapid or irregular heart beat Swelling of face, tongue, lips, throat, joints, hands, or feet

22. The causative antigens causing anaphylaxis Blood products ß-lactam antibiotics X-ray contrast agent Other drugs

23. Anaphylaxis

24. Treatment for anaphylaxis Immediate treatment with adrenaline is imperative Adrenaline is an antagonist to the effects of the chemical mediators on smooth muscle, blood vessels and other tissues. Treatment is based on the severity of the reactions

25. Treatment for anaphylaxis 0.5 ml adrenaline 1:1000 IM should be given After symptoms resolve, an oral antihistamine and IV steroids should be given for 24 hr.

26. Prophylaxis of anaphylaxis Routine skin testing before giving drugs If X ray contrast is to be used in a patient, the patient should be pretreated with a steroid if there is a history of allergies

27. Thank you…