- I.V. admixture: Combination of parenteral dosage forms for administration as a single entity.
- I.V. fluids are used as vehicles for other parenteral drugs (additives). The number of additives can be up to 6 additives in the same I.V. fluid.
Reasons to use i.v. fluids:
1.Convenience and time saving
2. Reduction in the number of injections
3.Treating several conditions simultaneously
4. Drugs can be given in controlled increments
2. Reduction in the number of injections
3.Treating several conditions simultaneously
4. Drugs can be given in controlled increments
- I. V. Admixture incompatibility:
Refers to therapeutic, physical, and chemical problems that may arise when parenteral drugs are combined and administered with I. V. Fluids.
A)Therapeutic (pharmacological) incompatibility
1- Undesirable anatgonism: penicillin or cortisone antagonises heparin effect
2- Synergism: calcium ion enhances digoxin effect
2- Synergism: calcium ion enhances digoxin effect
B) Physical incompatibility
1.Precipitate formation:
- sodium salts of weakly acidic drugs such as phenobarbital sodium, or phenytoin sodium are precipitated in acidic pH I.V fluids.
- Weakly basic drugs (dramamine HCl) precipitate in alkaline pH I.V fluids.
- Calcium salts ppt. In presence of NaHCO3
- Low soluble drugs precipitate on dilution e.g. valium
- sodium salts of weakly acidic drugs such as phenobarbital sodium, or phenytoin sodium are precipitated in acidic pH I.V fluids.
- Weakly basic drugs (dramamine HCl) precipitate in alkaline pH I.V fluids.
- Calcium salts ppt. In presence of NaHCO3
- Low soluble drugs precipitate on dilution e.g. valium
2.Color change:
Keflin and Garamycin give yellow precipitate with I.V Fluids.
C) Chemical incompatibility
Due to instability conditions:
- Penicillins are stable at pH 6.5 for 24 hrs, but decompose at extreme pH (3.5 or in alkaline i.V. Fluids)
- Aminophylline injection added to multivitamins (B-complex and Vit. C) results in alkaline pH (unsuitable for vitamins)
- Tetracyclines are inactivated in presence of ca++ ions
- Penicillins are stable at pH 6.5 for 24 hrs, but decompose at extreme pH (3.5 or in alkaline i.V. Fluids)
- Aminophylline injection added to multivitamins (B-complex and Vit. C) results in alkaline pH (unsuitable for vitamins)
- Tetracyclines are inactivated in presence of ca++ ions
Minimizing parenteral incompatibility:
1.Using fresh solutions
2.Refrigeration
3.Few additives
4.Knowledge about parenteral therapy
5.Using aseptic techniques
2.Refrigeration
3.Few additives
4.Knowledge about parenteral therapy
5.Using aseptic techniques