antineoplásicas Drugs

Neoplasia: there are different forms to fight the tumors:

• Surgery for operables tumors
• Quimioterápicas or antineoplásicas drugs
• Inmunoterapia
• Hormonoterapia (for hormonodependientes tumors)
• X-ray

Neoplasias sanguineous treats by chemotherapy. One is to attack the tumor although the individual suffers, because the tumor is due to eliminate. In veterinary medicine one only tends to improve the quality of life.

Quimioterápicos

They are drugs that attack cells, that have specificity on tumorlike cells and the normal ones that they are multiplied: bony marrow, epitelios, TGI, gónadas, skin, mucous and linfoide weave.

These drugs must attack little the normal cells. The specificity depends on the fraction of growth of the weave (the more high the fraction, the more sensible the weave, is tumorlike or not).

• Sensible tumors: small tumors with high fraction of growth

• Great tumors: detectable clinically, they are less sensible and they arrived at the top of his growth

Antitumorales

They are cycle specific or inespecíficos.

• Specific: They do not act in G0. Phase specific (act in a phase) or phase can be inespecíficos (they act in more than a phase). They are less toxic. They require greater time of contact with the tumor.

• Inespecíficos: They act in anyone of the phases of the cellular cycle and in addition in G0. They are very toxic.

The antitumorlike ones are used in cycles (once for week until a determined white globule account, for example), to give time to the bony marrow to recover.

The granulocitos are affected, reason why there is predisposition to the infections.

Not to repeat the treatment before the count of targets is standardized because it can attack stem cells. If it returns to occur before the bony marrow recovers, it attacks stem cells because they leave G0 and they enter the cycle; however when standardizing itself, stem cells happens again to G0 and they are not attacked by the antineoplásicos.

When the tumor is great, surgery is made later and chemotherapy because the cells leave G0 and enter mitosis.

The more great it is the tumor, is the more chance of mutation with resistance, reason why the drugs are used when they are small. The great tumors less are attacked to be less irrigated.

Classification

Cradle in the chemical structure and way of action and moment of the cellular cycle in which they act 

• GCC: they are important, cross the BHE. They are more active on neoplasias linfoproliferativas. In addition they diminish the inflammation and they improve the quality of life. They occur during all the life, day by means, and to the minimum effective dose.

• Estrogens: in order to treat tumors that respond to androgens (also for breast tumors).

• Testosterone (or tamoxifeno - it is antiestrogens): in order to treat tumors that respond to estrogens (also for breast tumors).

According to the mechanisms it can have tumorlike resistance: they can prevent the entrance; they can increase the exit (it increases the pumping of the antineoplásico towards the outside); to alter the substrate (to make alternative routes, to change chemical structures, to increase the efficiency of repair of the DNA).

The antineoplásicos are not used single. They are associated together or in sequential form. They are chosen according to action mechanism, to act in the same phase, sensitivity of the tumor (they are chosen most active for that tumor).

Toxicity

• Mielosupresión (except vincristina and bleomicina): The mielosupresión can be early (for the cycle-specific ones, but the recovery is fast) or delayed (for the cycle-inespecíficos).

• Ulcers, vomits, diarrea, nauseas (alquilantes, antimetabolitos and ATB)

• Mutation, carcinogénesis and alteration of the reproductive activity (alquilantes)

• Ciclofosfamida: vesicales alterations with hemorrhages and can produce carcinoma of vejiga

• SNC: the vincristina produces neurological alterations, depression, hiperexcitabilidad (fluorouracilo)

• Kidney: the ciplastino produces acute tubular necrosis, reason why slow EV and with much hidratación is due to give (manitol and furosemida to wash renales túbulos). The metotrexato precipitates in the túbulos, producing insufficiency; it is possible to be hydrated or to be sobrehydrated

• Weave necrosis and irritation: they produce the vegetal ATB and alkaloids, reason why EV are due to give, and if they extrude they produce necrosis

• Myocardium: irreversible cardiac alterations (doxorrubicina - it is of ample epirrubicina phantom and). They form free radicals with alterations in the miocárdica membrane

Routes

Per you, EV, intraarterial, intracavitaria (with circumscribed tumors, for example intravesical, intraperitoneal).

Notes

Those that they arrive at the central system nervous are:

• Vincristina

• Vinblastina

• Prednisona

• 5-Fluorouracilo

Many must activate:

• Ciclofosfamida

• Metotrexato (less)

  Extraido article of http://www.lafacu.com/apuntes/medicina/default.htm

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