Drug Interactions

Related Procedures

Pharmacological interactions: additive, synergistic, antagonistic, and potentiation effects. Drug interaction identification tested on PTCB exam.

Related drug class: ACE inhibitors includes lisinopril, enalapril, ramipril. Mechanism: Block angiotensin-converting enzyme, decrease angiotensin II, cause vasodilation and decreased aldosterone.

Calculation Methods

Calculations relevant to drug interactions in pharmacy:

days supply: quantity dispensed / (dose * frequency). Example: #90 tabs, 1 tab TID = 90/(1*3) = 30 days

flow rate: Volume (mL) * drop factor / time (min). Example: 1000mL * 15gtt/mL / 480min = 31.25 gtt/min

Step-by-Step Procedure

Pharmacological interactions: additive, synergistic, antagonistic, and potentiation effects. Drug interaction identification tested on PTCB exam.

Related drug class: Benzodiazepines includes lorazepam, diazepam, alprazolam, midazolam. Mechanism: Enhance GABA-A receptor, increased chloride conductance, CNS depression.

Documentation

Proper documentation of drug interactions follows facility policies and regulatory requirements. All entries must be dated, timed, and signed. Errors are corrected with a single line through the incorrect entry, initialed and dated. Never erase or cover with correction fluid.

Historical Context

Pharmacy regulation in the U.S. began with the Pure Food and Drug Act of 1906. The Federal Food, Drug, and Cosmetic Act of 1938 required proof of safety. The 1962 Kefauver-Harris Amendment added efficacy requirements. Understanding drug interactions within this regulatory history helps pharmacy technicians appreciate why current standards exist, as each major regulation was prompted by a public health crisis.

Exam Focus Areas

On the Ptcb, Medical Assistant exam(s), questions about drug interactions typically test:

1. Federal and state regulations governing practice
2. Mathematical calculations: dosage, days supply, dilutions, and compounding
3. Drug interactions and contraindications that affect patient safety