Pharmacology Dosage Forms and Administration

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Questions and Answers

Which of the following are dosage forms for oral administration?

Injections

Ointments

Tablets (correct)

Suspensions (correct)

Which of the following routes of administration uses suppositories?

Nasal

Rectal (correct)

Topical

Oral

In pharmacokinetics, the term ______ refers to the rate at which a drug is absorbed into the bloodstream.

absorption

What are the three phases of adherence to medicines?

Initiation, Implementation, Discontinuation Signup and view all the answers

The concept of adherence has replaced the concept of compliance.

True Signup and view all the answers

What factors should be considered when checking the dose, frequency, and strength of prescribed medicines?

Patient's age Signup and view all the answers

What is a therapeutic window?

The range of drug concentrations in the body that achieves the desired effect without toxicity. Signup and view all the answers

Which of these factors does NOT influence drug absorption from the gastrointestinal tract?

Drug radiant energy Signup and view all the answers

Why monitor drug treatment in clinical practice?

To see whether there is a therapeutic response, to assess drug toxicity, and to assess adherence to treatment. Signup and view all the answers

Which of the following drugs is NOT commonly monitored for plasma concentrations?

Ibuprofen Signup and view all the answers

The term used for monitoring the levels of medication in the blood is __________.

Therapeutic Drug Monitoring Signup and view all the answers

Drug interactions can affect drug plasma concentrations.

True Signup and view all the answers

Name one factor that modifies drug plasma concentrations for a given dose.

Formulation, genetic variation, environmental variation, effects of disease, drug interactions. Signup and view all the answers

What is the risk if the plasma concentration of a drug exceeds the maximum safe concentration?

Risk of toxicity Signup and view all the answers

In which situation is plasma drug concentration measurement NOT useful?

When treatment is not ongoing Signup and view all the answers

What does a low toxic to therapeutic ratio imply?

It means a narrow therapeutic window, where there is a high risk of toxicity with increased concentration. Signup and view all the answers

Pharmaceutical response correlates better with the dose than with blood concentration.

False Signup and view all the answers

The maximum safe concentration of a drug is abbreviated as __________.

MSC Signup and view all the answers

Which method is NOT used for dosing treatment using Therapeutic Drug Monitoring?

Using feedback from the patient only Signup and view all the answers

Study Notes

Therapeutic Drug Monitoring (TDM)

TDM is essential for assessing drug efficacy, toxicity, and patient adherence.
Monitoring seeks to determine therapeutic responses and appropriate drug levels in the body.

Measurable Drugs for TDM

TDM is performed on specific drugs like aminoglycosides (gentamicin, tobramycin), anticonvulsants (phenytoin, carbamazepine), cardiac glycosides (digoxin), and immunosuppressants (cyclosporin, tacrolimus).
Individual responses to medication vary due to absorption, distribution, metabolism, and excretion differences.

Factors Influencing Drug Concentrations

Drug formulation affects absorption rates; liquid digoxin is better absorbed than tablets.
Genetic variations can alter drug metabolism, e.g., fast and slow acetylators.
Environmental factors, such as smoking, can accelerate drug clearance.
Diseases impact drug elimination; renal impairment increases gentamicin and lithium retention, while hepatic issues affect phenytoin metabolism.

Plasma Concentration Dynamics

Plasma concentrations are key in determining the drug's therapeutic and toxic effects.
Therapeutic window comprises:
- MEC (minimum effective concentration)
- MSC (maximum safe concentration)
Clinical assessment should complement plasma concentration measurements in treatment decisions.

Clinical Usefulness of TDM

TDM enables dosage adjustments for individual patients, minimizing toxicity while maximizing therapeutic effects.
Many drugs show a stronger correlation of effects with blood concentrations than dosages.
Clinical response evaluation is crucial alongside plasma concentration data.

Modifying Drug Effects

Drug interactions can intensify toxicity (e.g., aminoglycosides with nephrotoxics).
Electrolyte balance impacts drug sensitivity; hypokalaemia heightens digoxin effects.
Age-related sensitivity increases in older populations.
Bacterial resistance can occur despite therapeutic plasma concentrations.

Criteria for TDM Efficacy

Clinical challenges exist in interpreting therapeutic and toxic effects, justifying plasma concentration measurements.
A strong relationship between drug levels and effects must exist for TDM to be useful.
Drugs with narrow therapeutic windows (gentamicin, lithium, phenytoin) are prime candidates for TDM evaluation.

Circumstances Requiring TDM

Assessing patient adherence through low concentrations (given adequate dosage).
Individualizing therapy by tailoring dosages.
Diagnosing under-treatment in the face of poor clinical responses.
Monitoring to prevent toxicity, particularly during treatment initiation.
Identifying interactions when new drugs are introduced.
Terminating treatment based on low plasma levels.

Proper Use of Plasma Concentration Measurements

Routine measurements need a clear clinical purpose.
Blood sample timing, dealing with steady states, and correct sample types are crucial.
Analytical techniques must be precise and accurate.
Interpretation should be holistic, integrating clinical signs with concentration data.

Analyzing Deviations in Plasma Values

Investigate potential factors for variances in plasma levels, including concurrent medications, adherence, medication errors, and sample handling.

Understanding Patient Variability

Population pharmacokinetics (PK) account for demographic and clinical factors influencing drug behavior.
Two types of PK effects:
- Fixed effects: accounted for by averages and demographics.
- Random effects: address variability between individuals.

Dosing Strategies

TDM fosters dose individualization based on actual plasma concentrations versus population means.
Utilizes predictive methods and pharmacokinetic models for dosage recommendations.

Concentration-Time Dynamics

Plotting concentration-time curves illustrates how drug levels change post-administration.
Different formulations and dosing regimens affect peak concentrations and therapeutic windows.
Oral and intravenous routes show distinct pharmacokinetic profiles, influencing clinical application.### Therapeutic Window
Describes the range of drug concentration in the body that is effective without being toxic.
Concentration versus time curve illustrates drug absorption, reaching a steady state.

Administration of Medicines

Medicine consists of active ingredients combined with excipients.
Various dosage forms are available depending on administration routes:
- Oral: Includes solutions, capsules, tablets, syrups, and powders.
- Rectal: Utilizes suppositories and ointments.
- Topical: Ointments, creams, lotions, and gels applied directly to skin.
- Parenteral: Administers injections, implants, and dialysis solutions.
- Lungs: Involves inhalations and aerosols.
- Nasal: Solutions and inhalations are common.
- Eye: Solutions and ointments for ophthalmic use.
- Ear: Solutions and ointments for otic application.

Therapeutic Regimens

Balances efficacy and safety by assessing pharmacokinetic factors: absorption, distribution, metabolism, and excretion.
Clinical factors include patient state (age, weight), management of multiple drug therapies, and adherence to medication regimens.

Drug Absorption Dynamics

Liberation from tablets increases surface area exposed to gastrointestinal fluids for enhanced drug absorption.
The dissolution rate affects how quickly drugs enter systemic circulation:
- Intact tablets → disintegration → granules → absorption.
Factors influencing drug absorption include gastrointestinal conditions, solubility, pH levels, and food interactions.

Pharmacokinetics vs. Pharmacodynamics

Pharmacokinetics deals with drug behavior (dosage regimen, plasma concentration).
Pharmacodynamics is about the drug's effects and feedback regarding therapy optimization.

Medication Regimen Monitoring

Indications for treatment must align with prescribing guidelines.
Verify any changes in regular treatment protocols.
Appropriate dosing must consider patient-specific factors including age, organ function, and co-morbidities.
Assess drug interactions and therapeutic duplications.
Regular monitoring ensures necessary dose adjustments are made.

Adherence to Medicines

Adherence is defined as patients taking medications as prescribed, involving three phases: initiation, implementation, and discontinuation.
Management of adherence monitors patient processes and supports them in maintaining their regimen.
Shift from "compliance" (enforcement) to "adherence" (patient engagement) reflects a change in approach to medication management.

Summary of Product Characteristics (SPC)

Key components include:
- Name and composition of the medicinal product.
- Clinical particulars covering indications, dosage, use precautions, interactions, and effects.
- Pharmacological properties including kinetic and dynamic data.
- Regulatory information provides access for further details on medications.

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Description

This quiz explores essential concepts in pharmacology, focusing on oral administration dosage forms, routes that use suppositories, and pharmacokinetics. It also covers the three phases of medication adherence and critical factors in checking prescriptions. Test your knowledge on these important topics in drug administration and patient care.