Drugs can cause unwanted side effects through several mechanisms. Side effects may result from the same pharmacological action as the therapeutic effect, a different aspect of the drug's action, or an effect that is therapeutic in one context but a side effect in another. Secondary effects are an indirect consequence of the primary drug action. Toxic effects occur from excessive pharmacological action due to overdose or prolonged use, potentially damaging organs like the CNS, CVS, kidneys, lungs, skin, or blood. Intolerance is an inability to tolerate adverse effects at therapeutic doses due to a low individual threshold to the drug's action.

1. Drug Induced Side effects
Presented
By
Kisto. J. M
Krishnakamal.kn

2. What is Drug?
(drug) Any substance (other than food) that is used to prevent, diagnose,
treat, or relieve symptoms of a disease or abnormal condition.
A pharmaceutical drug, also called a medication or medicine, is a chemical
substance used to treat, cure, prevent, or diagnose a disease or to promote
well-being. Traditionally drugs were obtained through extraction from
medicinal plants, but more recently also by organic synthesis.

3. What is Drug Induced Side effects?
Unwanted or Unexpected Drug Reactions
Side effects, also known as adverse reactions, are unwanted undesirable
effects that are possibly related to a drug. Side effects can vary from
minor problems like a runny nose to life-threatening events, such as a
heart attack or liver damage.
A drug-induced state or reaction is provoked by a drug. Narcotic overdoses
cause a number of drug-induced deaths. Psychosis brought on by drug use
is called drug-induced psychosis. A drug-induced state or reaction is
provoked by a drug.

4. Side effect based on same action as therapeutic
effect
• Ex: Atropine - anticholinergic drug used as for its anti secretory
effect - produces dryness of mouth as side effect.
• Ex: Glyceryl trinitrate - dilates the peripheral vasculature and
relieves angina-produces postural hypotension and throbbing
headache as side effect.

5. Side effect based on different facet of action
Ex: Promethazine – antiallergic drug produces sedation as a side
effect which is unrelated to the therapeutic action of the drug.
Ex: Estrogens – antiovulatory action cause nausea as a side effect.

6. An effect may be therapeutic in one context
but side effect in another context
• Ex: Codeine-drug used in the treatment of cough-produces
constipation as side effect, the later being used as
therapeutic effect in traveller's diarrhoea

7. 2. SECONDARY EFFECTS
Indirect consequence of a primary action of the
drug.
Ex: Tetracycline antibiotic-causes of bacterial flora
and paves the way for super infection.

9. 3. TOXIC EFFECT
• Result of excessive pharmacological action of drug due to over dosage or
prolonged use.over dosage-absolute (accidental, homicidal, suicidal)
• Relative (relating to some other cause.
• Ex: usual dose of gentamicin . in presence of renal failure.) Manifestations
are often predictableand dose related.
Organs commonly involved in drug toxicity are,
CNS, CVS, Kidney,Lungs,Skin, Blood forming organs

10. 3. TOXIC EFFECT
Result from,
Functional alteration. Ex: high dose of atropine-delirium
Drug induced tissue damage. Ex: hepatic necrosis from paracetamol over dosage.
Extension of the therapeutic effec itself. Ex: coma by barbiturates, bleeding due to
heparin.
A different action of the drug. Ex: morphine-respiratory failure.

11. 4. INTOLERANCE
• Inability of an individual to tolerate the adverse effect of a medication, generally
at therapeutic doses.
• Converse of tolerance and indicative of a low threshold of an individual to the
action of the drug.
• Ex: Triflupromazine(antipsychotic)-single dose. induces muscular dystonia.
• Ex: few doses of Carbamazepine (antiepileptic) may cause ataxia.