**14.15. Patient compliance and rational use of drugs**

Drug treatment of any kind is often compromised by lack of full compliance by the patient. The common errors of compliance to a regimen by a patient include; omission in taking the drug, wrong timing of dosages, premature termination of therapy or using additional medications. In order to improve patient compliance, the patient should be made to under‐ stand the nature and prognosis of the illness and what to expect from the medication by detailing both the acceptable and undesirable unwanted effects as well as signs of efficacy that may help enforce compliances.

**14.18. Non-dose related adverse drug reactions**

Drug allergies can be classified into five categories:

include;-penicillins, streptomycin, local anaesthetics etc.

improperly matched blood can yield this type of reactions.

topical antibiotics and antifungal drugs.

against adverse drug effects.

**14.19. Types of drug allergies**

**Type I**

**Type II**

**Type III**

reactions. **Type IV**

**Type V**

These include immunologic reactions and are related to the surface proteins present on βhumans lymphocytes (HLA antigens) which are important in the function of T-lymphocytes. The association of HLA antigens with foreign antigens stimulates T-lymphocytes. Some of these antigens expressed by major histocompatibility complex (MHC) genes have been associated with an increased risk of adverse drugs e.g. nephrotoxicity from penicillamine is increased in patients with HLA types B8 and DR 3 while patients with HLA- DR, 7 are protected

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This anaphylaxis or immediate hypersensitivity reactions; the body reacts within five to thirty minutes. The IgE molecules fixed to mast cells and basophil leucocytes release histamine and other pharmacological mediators such as kinins. Drugs likely to cause are anaphylactic shock

In these reactions, the circulating antibody of 1gG, 1gM or 1gA interacts with the drug combined with a cell membrane protein to form a hapten-protein/antigen-Ab complex. This leads to the activation of the complement leading to cell lysis of phagocytic attack of the cell with the complex. Drugs such as the cephalosporins, penicillins, quinine and transfusion of

In this type of allergy, the immune complex reactions initiate an inflammatory response due to the combination of the excess drug- protein complex with the IgG in circulation. The complex thus formed is deposited in the tissues and causes activation of the complement and damage of capillary endothelium. This type of reaction is manifested mostly as fever, arthritis, and/or enlarged lymph nodes. Penicillins, sulphonamides and streptomycin may elicit type III allergic

This is the cell-mediated or delayed hypersensitivity reactions in which the T - lymphocytes are sensitized by a hapten to form protein-antigenic complex such that when the lymphocytes come into contact with the antigen, an inflammatory response ensues. Type IV reactions are exemplified by contact dermatitis caused by local anaesthetic areas, antihistamine areas,

These are pseudo allergic reactions, that resemble allergic reactions clinically, but for which no immunological basis can be found, e.g. asthma and skin rashes caused by aspirin. Admin‐

Patients frequently discontinue taking a medication such as septrin because they have not been told the necessity of continuing with the drug after the acute symptoms have subsided.

The effectiveness of physician-patient communication is inversely related to the error rate in the taking of drugs. A physician might prescribe a drug to be taken three times a day with meals for a patient who either eats only twice a day or sleeps all day and works at night. Therefore, an exploration of the patients eating, sleeping and working habits is necessary before a prescription is given.

The educational level of a patient may also require that the prescription is carefully worded and oral instructions given in the primary language of the patient since when such patients take three or more medications they are less likely to use them properly. It is therefore important to provide identifying symbols for each medication e.g. "Heart pill" or "sugar pill"and to reduce the doses into once or twice daily regimens.
