Intravenous drug administration

After intravenous drug administration, a log-convex concentration decline points to a multi-exponential function. For the most frequent case, a bi-exponential equation with the inter-compartment rate constants (k 2) and (k21) can be fitted. 

Parenteral drug administration means the giving of a drug by the subcutaneous (SC), intramuscular (IM), intravenous (IV), or intradermal route (Fig. 2-5). Other routes of parenteral administration that may be used by the primary care provider are intralesional (into a lesion), intra-arterial (into an artery), intracardiac (into the heart), and intra-articular (into a joint), hi some instances, intra-arterial dragp are administered by a nurse. However, administration is not by direct arterial injection but by means of a catheter that has been placed in an artery. 

Lukas, S.E. Griffiths, RR. Bradford, L.D. Brady, J.V. Daley, L. and DeLorenzo, R. A tethering system for intravenous and intragastric drug administration in the baboon. Pharmacol Biochem Behav 17 823-829,... 

Drugs used for the termination of hemodynamically stable VT are presented in Table 6-11. Intravenous drug administration... 

ACTH, adrenocorticotropic hormone or corticotropin FDA, Food and Drug Administration HPA, hypothalamic-pituitary-adrenal IV, intravenously. aThe 250 meg dose has also been administered intramuscularly in an outpatient setting. The 1 meg dose is not FDA-approved. 

Parenteral administration of drugs by intravenous (IV), intramuscular (IM), or subcutaneous (SC) routes is now an established and essential part of medical practice. Advantages for parenterally administered drugs include the following rapid onset, predictable effect, predictable and nearly complete bioavailability, and avoidance of the gastrointestinal (GI) tract and, hence, the problems of variable absorption, drug inactivation, and GI distress. In addition, the parenteral route provides reliable drug administration in very ill or comatose patients. 

Finally, intravenous drug administration and the sharing of needles and syringes is common among opiate addicts this creates a serious risk of cross-infection. Many studies have shown a high incidence of HIV and hepatitis B and C among heroin addicts. This risk is somewhat reduced in medically controlled narcotic prescription... 

The single-dose toxicity studies were performed in two mammalian species, rat and mouse, by the route used in clinical practice, that is oral, as well as that ensuring adequate systemic exposure to the drug, that is intravenous. The subacute (3 months) toxicity studies were correctly carried out in the two animal species (rat, dog) in which also the pharmacokinetics was studied. Since in accordance with the International Conference on Harmonization (CPMP/ICH/286/95), 3-month toxicity studies support clinical trials for up to 1 month s duration (the longest duration of drug administration in clinical use), chronic toxicity studies have not been performed. 

Just as new drugs must be tested in animals by the route to be used in humans, so must they be tested in volunteers using the intended route for patients. But there are clear benefits in testing all drugs when going into humans for the first time using intravenous infusions, even if systemic exposure in patients will be achieved by another route. These benefits relate primarily to the fact that intravenous infusion allows for precise control of drug administration. 

In the case of drug administration by an intravenous infusion, the average steady state concentration (Css) is obtained by the equation,... 

Johnson and colleagues have summarized the major toxicological observations made after administration of vinblastine or vincristine to other animals Ib). In rabbits and cats intravenous doses of 0.2 mg/kg vincristine were lethal after the second to the fifth dose on a schedule involving drug administration two to three times a week. Signs consistent with neurotoxicity were observed in rabbits and cats for example, a head drop phenomenon, characteristic of neuromuscular dysfunction, was observed in rabbits, and clonic convulsions were observed in cats. Vincristine is lethal to dogs when administered at 0.05 mg/kg, intravenously, five times in a 1-week period. Vincristine is lethal to monkeys when administered five times on a schedule of 1 mg/kg weekly comparable toxicity is observed when the drug is administered more frequently (daily) at lower doses (e.g., 0.2 g/kg). 

Acetylcholine does not have therapeutic value as a drug for intravenous administration because of its multi-faceted action and rapid inactivation by cholinesterase. Likewise, it is possible for a collaptoid state to develop, and arterial pressure can rapidly fall and the heart can stop. However, it is used in the form of eye drops to cause miosis during cataract surgery, which makes it advantageous because it facilitates quick post-operational recovery. A synonym of this drug is miochol. 

All drug effects are the result of complex interaction between the drug, the patient and the illness. Extrinsic factors, such as speed of administration intravenously, diet, chemical exposures (including other drugs) and many other factors, can also modify drug response. 

Combinations of amphotericin-B with flucytosine are sometimes used to reduce the occurrence of resistance. Amphotericin-B is not absorbed from the gastrointestinal tract which necessitates intravenous administration. It is 90% protein bound and widely distributed, except for the CNS. For the treatment of fungal meningitis therefore only intrathecal drug administrations can be effective. Amphotericin-B is eliminated very slowly in urine, mainly in an inactive form, with an elimination half-life of about 24 hours which can increase to up to 15 days with repeated doses. 

Except for intravenous administration, all routes of drug administration require that the drug be transported from the site of administration into the systemic circulation. A drug is said to be absorbed only when it has entered the blood or lymph capillaries. The transport of drugs across membranes entails one or more of... 

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