Drug interaction

Ashiq N.V ( 56th )

Jithin dev ( 56th )

Athira ( 56th )

•The Drug whose Activity is effected by such an

Interaction is called as a “Object drug.”

• The agent which precipitates such an

interaction is refered to as the “Precipitant”.

1. A woman on phenytoin uses OCP

-Phenytoin Induces Microsomal enzymes and Increases degradation of steroidal hormones like OCP

mnemonic "GPRS Cell Phone"

GriseofulvinPhenytoinRifampicinSmokingCarbamazepinePhenobarbitone

2. Use of diuretic in a psychiatric patient on Lithium

-Diuretics by causing Na+ loss promote proximal tubular reabsorption of Li+. Thus plasma levels of Li+ rise.

3.Use of Ciprofloxacin with Theophylline

-Ciprofloxacin increase Plasma concentration of Theophylline by inhibiting CYP1A2 and can cause toxicity.

SICKFACES.COM

1. Sodium valproate2. Isoniazid3. Cimetidine4. Ketoconazole5. Fluconazole6. Alcohol7. Chloramphenicol8. Erythromycin9. Sulphonamides10. Ciprofloxacin11. Omeprazole12. Metronidazole

4. Use of Astemizole with Erythromycin

-Erythromycin inhibits CYP3A4 which is enzyme metabolizing Astemizole. Thus the Astemizole level in blood rises resulting in a potentially fatal arrhythmia, torsades de pointes.

5. Use of Spironolactone with ACE inhibitors

-Spirinolactone is potassium sparing diuretic. ACE inhibiotors also cause hyperkalemia. Combining these can thus result in profound hyperkalemia.

6. For a Diabetic Patient with palpitation, Tab Propranolol 40 mg TDS and Insulin 60 U were given.

-Hypoglycemic symptoms like palpitation, tremors will be masked by non specific beta blocker like propranolol. Also glycogenolysis, gluconeogenesis in liver is also decreased by propranolol.

7. Use of Sucralfate and Antacid for a patient with Peptic Ulcer

-In an acid environment (pH <4), sucralfateundergoes extensive cross-linking to produce a viscous, sticky polymer that adheres to epithelial cells and ulcer.Antacids will decrease production acid and prevents sucralfatecrosslinking.

8. A diabetic Patient on Glibenclamide was prescribed Cotrimoxazole for UTI

-Cotrimoxazole displaces Glibenclamide from its protein bound form and thus increases risk of hypoglycemia

9. A patient on Verapamil prescribed Propranolol

-CCB like verapamil and beta-blocker propranolol combination cause Hypotension, Bradycardia and prolongation of PR interval which may even result in CHB

REDUSING THE RISK OF DRUG

INTERACTIONS:

1.Identify the patients risk factors.

2.Take through drug history.

3. Report ADR

4.Consider therapeutic alternatives.

5Avoid complex therapeutic regiments when possible.

6.Educate the patient.

7.Monitor therapy.