Administration, drugs intramuscular route

Intravenous administration of a drug produces the most rapid drug action. Next in order of time of action is the intramuscular route, followed by the subcutaneous route Giving a drug orally usually produces the slowest drug action. 

Avoid the subcutaneous and intramuscular route of drug administration in patients in any form of shock... 

Drugs are administrated by intravenous routes or ex-travascular routes including oral, sublingual, subcutaneous, intramuscular, rectal (by enema or suppository), and transdermal. Available dosage forms include suspensions, immediate-release capsules or tablets, sustained-release capsules or tablets, and enteric-coated capsules or tablets that resist dissolution in the acidic pfi of the stomach. 

The advantages of administration by intramuscular injection are that the muscle can act as a depot, and the rate of disappearance of drug from the site of injection can be calculated. Inhalational, intranasal, and intratracheal administration are normally reserved for vapors and aerosols including anesthetics. Absorption is facilitated by small-sized particles, high lipid solubility, sufficient pulmonary blood flow, and a large absorptive surface area, as it is present in healthy lungs. Administration by these routes can be very rapid when several of the factors favoring increased absorption are combined. 

Carbapenems penetrate body tissues and fluids well, including the cerebrospinal fluid. All are cleared renally, and the dose must be reduced in patients with renal insufficiency. The usual dose of imipenem is 0.25-0.5 g given intravenously every 6-8 hours (half-life 1 hour). The usual adult dose of meropenem is 1 g intravenously every 8 hours. Ertapenem has the longest half-life (4 hours) and is administered as a once-daily dose of 1 g intravenously or intramuscularly. Intramuscular ertapenem is irritating, and for that reason the drug is formulated with 1% lidocaine for administration by this route. 

In practice, it is unlikely to have compartmental models with initial conditions unless there are residual concentrations obtained from previous administrations. Drugs are administered either by extravascular, or intravascular in single or repeated experiments. Extravascular routes are oral, or intramuscular routes, and intravascular are the constant-rate short- and long-duration infusions. 

Following intramuscular (IM) administration, drugs must cross one or more biological membranes in order to enter the systemic circulation. Intramuscular injection is used mainly for drugs and vaccines that are not absorbed orally, for example, aminoglycosides, insulin, and hepatitis vaccine. The IM route is often used for sustained medication and specialized vehicles, such as aqueous suspensions, oily vehicles, complexes and microencapsulation, which has been developed for slow delivery of drugs by this route. ... 

Aronson JK. Routes of drug administration 5. Intramuscular. Presc J 1995 35 32-6. 

IL-2 usually is administered intravenously, although the subcutaneous and intramuscular routes are used. The infusion can produce. severe hypotension and life-threatening cardiovascular toxicity when given at the maximally tolerated dose. Patients receiving such a do.se must be monitored closely, and facilities mu.st be available to treat them for hypotension, tachycardia, pulmonary edema, and (occasionally) delirium. The drug is rapidly cleared from the bloodstream following parenteral administration. The elimination is biphasic for an Intravenous bolus injection. The pritnary route of elimination is renal, with catabolism occurring in the renal tubules. 

Drug Metabolic Products - Pharmacokinetics Cephalothin was partially converted to deacetylcephalothin after parenteral administration to experimental animals and to man.23 in the dog, initial excretion was distributed equally between cephalothin and its deacetyl metabolite later excretion showed a preponderance of the metabolite over the parent compound. Cephalothin persisted over a longer period of time when administered by the intramuscular route than when given intravenously. In man, the total amount excreted in the urine was... 

Parenteral administration via the intramuscular route should be avoided with diazepam and chlordiazepoxide secondary to variability in the rate and extent of drug absorption. Intramuscular lorazepam provides rapid, reliable, and complete absorption however, the preparation requires refrigeration. 

Deferoxamine deferoxamine mesylate, desferal mesylate) is poorly absorbed after oral administration, and parenteral administration is required in most cases. For severe iron toxicity (serum iron levels >500 /rg/dL), the intravenous route is preferred. The drug is administered at 10-15 mg/kg/h by constant infusion. Faster rates of infusion (45 mg/kg/h) have been used in a few cases rapid boluses usually are associated with hypotension. Deferoxamine may be given intramuscularly in moderately toxic cases (serum iron 350-500 )ig/dL) at a dose of 50 mg/kg with a maximum dose of 1 g. Hypotension also can occur with the intramuscular route. 

Pentamidine is available as the water-soluble isethionate salt, which is used both IV and as an aerosol. The drug can be used via the intramuscular route, but significant complications have been reported and. therefore, this route of administration is not recommended. The drug has fungicidal and antiprotozoal activity, but today, it is used primarily for treatment of PCP. 

Unlike the much-shorter-acting scopolamine, BZ s effectiveness by the oral route of administration is about 80% that of the intravenous or intramuscular routes (which are virtually identical). By inhalation, if disseminated at an optimal particle size (diameter about 1.0 pm), BZ is approximately 40% to 50% as effective as it is by injection. When applied to the skin dissolved in propylene glycol (a common vehicle for transdermal administration), apparent absorption is only 5% to 10% and the effects are delayed approximately 24 hours. (This is surprising since historical treatises suggest that belladonna drugs are readily absorbed from poultices.31)... 

Parenteral (injected) administration of drugs provides a solution to many problems associated with the oral delivery route. A drug injected into the blood circulation is considered to be completely bioavail-able thaefore, the quantity of the surfactants and otha inactive excipients in intravenous dosage forms are usually strictly limited. The most common alternative routes of parenteral drug administration are intramuscular or subcutaneous injections [2], Several otha injection routes are available to elicit rapid local reaction, such as intrathecal, intraarticular, and intracardiac. 

---