What does narrow therapeutic range mean?

All categories. Narrow therapeutic index (NTI) drugs are defined as those drugs where small differences in dose or blood concentration may lead to dose and blood concentration dependent, serious therapeutic failures or adverse drug reactions.

Narrow therapeutic index drugs are drugs where small differences in dose or blood concentration may lead to serious therapeutic failures and/or adverse drug reactions that are life-threatening or result in persistent or significant disability or incapacity.

Secondly, what is meant by a narrow therapeutic window? Drugs with a narrow therapeutic index The therapeutic window of a certain drug reflects the concentration range that provides efficacy without unacceptable toxicity. 4 Narrow therapeutic index (NTI) drugs have a narrow therapeutic window, hence doses must be titrated carefully and tight monitoring is usually required.

Also to know is, what does therapeutic range mean?

The therapeutic level of a drug in the bloodstream is the range within which that drug is expected to be effective without causing any serious problems to the patient. Your doctor can request a test to measure the amount of a specific drug in the serum portion of your blood.

What does a wide therapeutic index mean?

Therapeutic Index Speaker. A ratio that compares the blood concentration at which a drug becomes toxic and the concentration at which the drug is effective. The larger the therapeutic index (TI), the safer the drug is.

What is considered a safe therapeutic index?

Therapeutic Index The TI is a statement of relative safety of a drug. It is the ratio of the dose that produces toxicity to the dose needed to produce the desired therapeutic response. A clinician would consider a drug safer if it had a TI of 10 than if it had a TI of 3 (Figure 1).

Does digoxin have a narrow therapeutic range?

Most of the digoxin is eliminated unchanged by the kidneys. The therapeutic index of digoxin is very narrow. Severe toxic effects, such as cardiac arrhythmias (e.g. bradycardia, heart block, ventricular arrhythmias), may occur at plasma concentrations only twice the therapeutic plasma concentration range.

Does lithium have a narrow therapeutic range?

Lithium is now the drug of choice for treating bipolar affective disorders. Thus, lithium is an indispensable pharmaceutical component of modern psychiatric therapy. Unfortunately, lithium also has a narrow therapeutic index, with therapeutic levels between 0.6 and 1.5 mEq/L (Table 1) (2,3,4).

Does amiodarone have a narrow therapeutic index?

Amiodarone appears to be useful in the management of refractory arrhythmias. Amiodarone is difficult to administer because of its narrow toxic-therapeutic range and prolonged loading phase. More importantly, the first sign of antiarrhythmic failure may be manifest as sudden cardiac death.

Why does warfarin have a narrow therapeutic range?

Cytochrome P4502C9 and Vitamin K Epoxide Reductase. Warfarin has a narrow therapeutic range and untoward effects including serious bleeding are common. Warfarin decreases VKOR activity, which lowers levels of these coagulation factors.

Is levothyroxine a narrow therapeutic index drugs?

Levothyroxine has a narrow therapeutic index: both underdosage (subclinical hypothyroidism) and excessive dosage (subclinical hyperthyroidism) are associated with adverse symptoms and pathophysiological effects and are to be avoided.

Is warfarin a narrow therapeutic index?

Narrow therapeutic index (NTI) drugs are agents for which small changes in systemic concentration can lead to significant changes in pharmacodynamic response. Warfarin is a NTI drug for which substitution is now available and may occur routinely without the knowledge of the patient or practitioner.

What does it mean to have a low therapeutic index?

Definition of ‘therapeutic index’ It is easier to underdose or overdose drugs that have a low therapeutic index between an ineffective dose and a toxic dose. The therapeutic index of a drug is the ratio of the lethal dose to the effective dose, used in assessing the safety of a drug.

How do you find a therapeutic range?

Overview therapeutic index of a drug is the ratio of the dose that produces toxicity to the dose that produces a clinically desired or effective response. TD50 = the dose of drug that causes a toxic response in 50% of the population. ED50 = the dose of drug that is therapeutically effective in 50% of the population.

What is the meaning of therapeutic use?

therapeutic. Whether you’re talking about a therapeutic drug or a therapeutic exercise plan, something that is therapeutic helps to heal or to restore health. The adjective therapeutic can be traced all the way back to the Greek word therapeutikos (from therapeuein, meaning “to attend” or “to treat”).

Do you want a high or low therapeutic index?

A higher therapeutic index is preferable to a lower one: a patient would have to take a much higher dose of such a drug to reach the toxic threshold than the dose taken to elicit the therapeutic effect.

What is the ratio between a drug’s therapeutic effects and toxic effects called?

The therapeutic index (TI; also known as therapeutic ratio) is a ratio that compares the blood concentration at which a drug causes a therapeutic effect to the amount that causes death (in animal studies) or toxicity (in human studies) [1].

Why are trough levels important?

The purpose of drawing a trough level is to make sure the amount of medication in the patient’s blood stream is still high enough to be therapeutic. A “peak” is the highest level of the drug in the patient’s blood stream and is generally measured about 30 minutes after a dose of medication has completely infused.

What is the therapeutic level of lithium?

The therapeutic range for lithium has been established at 0.6 – 1.2 mmol/L. Within this range, most people will respond to the drug without symptoms of toxicity. Response and side effects will be individual.