Acyclovir

BRAND NAMES:

Zovirax- This main ingredient is acyclovir, it is available in tablets (400mg and 800 mg), oral suspension (400mg), and Ointment.

Sitavig- This main ingredient is acyclovir, available as Buccal tablets 50mg.

MECHANISM OF ACTION:

Cellular enzymes transform the monophosphate derivative into acyclovir triphosphate. Acyclovir triphosphate, an analog of deoxyguanosine triphosphate, competes with viral DNA polymerase to suppress it. The incorporation of acyclovir triphosphate into DNA causes chain termination because the absence of a 3'hydroxyl group precludes the attachment of further nucleosides. Acyclovir triphosphate has a considerably stronger affinity for viral DNA polymerase than its biological equivalent, resulting in a high therapeutic ratio.

PHARMACOKINETICS:

Absorption: Acyclovir has an oral bioavailability of 10-20%, however this falls with higher doses. Acyclovir ointment has an absorption rate of <0.02-9.4%. Acyclovir buccal pills and ophthalmic ointment have low absorption. The bioavailability of acyclovir is unaffected by meals.

Distribution: The mean volume of distribution of acyclovir is 0.6L/kg
Metabolism: Acyclovir is converted to acyclovir monophosphate by the action of viral thymidine kinases. Guanylate kinase converts acyclovir monophosphate into diphosphate. Acyclovir diphosphate is transformed to acyclovir triphosphate by nucleoside diphosphate kinase, pyruvate kinase, creatine kinase, phosphoglycerate kinase, succinyl CoA synthetase, phosphoenolpyruvate, carboxykinase, and adenylosuccinate synthetase. Acyclovir undergoes <15% oxidation to 9-carboxymethoxymethylguanine by alcohol dehydrogenase and aldehyde dehydrogenase, and 1% hydroxylation to 8-hydroxy-acyclovir by aldehyde oxidase.

Excretion: Acyclovir is primarily eliminated in the urine as an unaltered medication. 90-92% of the medication is excreted unaltered by glomerular filtration and tubular secretion. <2% of the medication is recovered in feces, while <0.1% is lost as CO2.

PHARMACODYNAMICS:

Acyclovir has a broad therapeutic window, as overdose is uncommon in otherwise healthy patients. Acyclovir is a deoxynucleoside analog that inhibits the action of viral DNA polymerase and the replication of several herpesviruses.

ADMINISTRATION:

Acyclovir is available in two forms: tablets and oral suspension. It is also available as a delayed-release buccal tablet to apply to the top gum of the mouth. The tablets and suspension are often given with or without meals, two to five times per day for five to ten days, beginning as soon as your symptoms appear. Do not crush, chew, or swallow delayed-release buccal pills.

Shake the oral suspension before measuring a dose. Use the dosage syringe provided or pharmaceutical dose measurement equipment.

DOSAGE AND STRENGTH:

The amount of medicine you take is determined by its strength. The amount of doses you take each day, the period between doses, and the duration of your medication use are all determined by the medical condition for which you are using it.

Oral suspension: 200 mg/ml;

Tablets: 400mg and 800mg.

CONTRAINDICATIONS:

The most absolute contraindication for acyclovir is hypersensitivity. Acyclovir has been found to cross the placenta while pregnant or lactating. Acyclovir has been observed to enter breast milk; however, it is typically considered compatible with nursing. Polyuric renal failure has occurred in large doses; thus, adequate hydration is required to avoid dehydration.

DRUG INTERACTIONS:

Drug interactions of acyclovir include:

Cimetidine, a medicine for stomach ulcers

Mycophenolate mofetil, a medicine given after organ transplants

Probenecid-gout drug

Aminophylline or theophylline—a medicine for asthma

SIDE EFFECTS:

Acyclovir may have major side effects:

Behavioral changes

Signs of kidney disorders include no urination, painful or difficult urination, and swelling in the feet or ankles.

Confusion

Common side effects of acyclovir include

Mouth ache while taking Buccal pills.

Rash, it was itching.

Headache

vomit

Nausea

Mild skin soreness.

Overdose symptoms include:

Symptoms may include agitation and seizures.

Extreme tiredness

Loss of consciousness

Swelling of the hands, feet, ankles, or lower legs.

Lower urination

TOXICITY:

The most serious side effect of parenteral acyclovir therapy is acute renal damage. AKI occurs at a frequency similar to other nephrotoxic drugs such as aminoglycosides. Acyclovir dosage adjustments are essential for maintaining baseline renal function and optimal body weight. A study on the pharmacokinetics of acyclovir showed that renal excretion of the drug is influenced by a patient's tubular secretion and glomerular filtration.

STORAGE CONDITIONS:

Drugs should be kept at room temperature. Maintain it between 15 °C and 25 °C, or 59 °F and 77 °F.

Keep it out of the light.

This drug shouldn't be kept in wet or humid environments.