Pharmacology Nurse Practice Test

The client taking Methotrexate should be monitored for abdominal pain, diarrhea or ulcerative stomatitis. Therapy may be discontinued with the presence of these toxic effects otherwise, hemorrhagic enteritis and death from intestinal perforation may occur.

Pharmacodynamics is the action of the drug on the human body. Pharmacokinetics is defined as what the body does with drug (Absorption, distribution, metabolism and excretion). Drug half-life is period of time it takes for a substance undergoing decay to decrease by half. Potency is a measure of how much a drug is required in order to produce a particular effect. Therefore, only a small dosage of a high potency drug is required to induce a large response.

Salicylates should be avoided to prevent bleeding tendencies as Methotrexate decreases platelet count. OTC drugs should not be taken by the client unless approved by the physician. Soft-bristled brush and electric razor (non-electrical razor poses more risk of bleeding) should be used to prevent bleeding. Sunscreen and protective clothing is used to prevent photosensitivity reactions.

Allopurinol (Zyloprim) is used to treat gout or kidney stones, and to decrease levels of uric acid in certain cancer patients. Methotrexate therapy increases the levels of uric acid in the blood resulting to gout. Symptoms of gout include edema and joint pain. To prevent hematologic toxicity (platelet levels are decreased) salicylates, NSAIDs, phenytoin, tetracycline and chlorampenicol should be avoided. Succimer is a chelating agent for lead poisoning.

If a dose is missed, it should be omitted. (Source: Davis Drug Handbook).

Zovirax is an antiviral medication used to treat recurrent genital herpes infections, shingles and chickenpox.

Superscription – client’s name, address and age. The symbol of take thou is also located here. Subscription – directions about the number of tablets or amount to be dispersed that is given to the pharmacist. Inscription – contains the drug name, strength and dose.

A standing order is carried out until the physician cancels it by another order or until a prescribed number of days elapse. PRN orders are administered when the client needs/requires it. (Example is Acetaminophen 500 mg q6h PRN for fever) Single orders are one-time orders where the drug is only given once at a specified time. (Example: Valium 10 mg PO at 10:00 am) A stat order signifies that a single dose is to be administered immediately and only one. (Example: Give Apresoline 10 mg IM stat).

a. The process of absorbing, distributing, metabolizing and excreting the drug. – pharmacokinetics b. Refers to the maximum response achievable from a drug. – efficacy c. Measure of the concentration of a drug at which it is effective. – potency d. A reduction in response to an agonist while it is continuously present at the receptor, or progressive decrease in response upon repeated exposure to an agonist. – desensitization

Contraindications of Mannitol include dehydration and hypersensitivity. Increase ICP, toxic overdose and acute oliguric renal failure are all indications of Mannitol administration.

Adverse Reactions of Methotrexate 1. Dizziness 2. Drowsiness 3. Headaches 4. Malaise 5. Anorexia 6. Nausea and vomiting 7. Hepatoxicity 8. Alopecia 9. Ulcerative stomatitis 10. Leukopenia 11. Chills and fever 12. Photosensivity 13. Thrombocytopenia 14. Hyperurecemia

Ectopic pregnancy is an indication of Methotrxate therapy. Death of rapidly replicating cells (e.g. cancer cells, choriocarcinoma, leukemia, carcinoma in different body parts and ectopic pregnancy) specifically the malignant ones is made possible through Methotrexate administration. Contraindications of Methotrexate: • Known allergic hypersensitivity to the drug • Pregnancy

a. ALT, AST – for liver function b. WBC and Platelet Count – blood studies c. Sodium and potassium – serum electrolyte d. BUN and creatinine – renal function

Mannitol is an osmotic diuretic that is indicated in the following conditions: 1. Acute oliguric renal failure 2. Toxic overdose 3. Edema 4. Increased intracranial pressure (ICP) 5. Intraocular pressure (IOP)

Drug half-life is the period of time required for the concentration or amount of drug in the body to be reduced or decrease by one-half.

Inscription – contains the drug name, strength and dose. Superscription – client’s name, address and age. The symbol of take thou is also located here. Subscription – directions about the number of tablets or amount to be dispersed that is given to the pharmacist.

Ung. Stands for ointment. (Source: Clinical Ocular Pharmacology by Jimmy D. Bartlett, Siret D. Jaanus) a. As directed – ut dict. b. Ointment – ung. c. Suspension – susp. d. Label – sig.

Hypokalemia increases the risk of digoxin toxicity, thus, the nurse should monitor potassium levels of a client taking Digoxin with Mannitol (adverse effects of Mannitol include hypokalemia).

Leucovorin Calcium. If Methotrexate is administered in high doses, the patient must receive Leucovorin Calcium rescue within 24-48 hours to prevent fatal toxicity. To prevent hematologic toxicity (platelet levels are decreased) salicylates, NSAIDs, phenytoin, tetracycline and chlorampenicol should be avoided. Edetate Calcium Disodium is used for the treatment of lead poisoning. Calcium gluconate is the antidote for magnesium toxicity.

A standing order is carried out until the physician cancels it by another order or until a prescribed number of days elapse. PRN orders are administered when the client needs/requires it. (Example is Acetaminophen 500 mg q6h PRN for fever) Single orders are one-time orders where the drug is only given once at a specified time. (Example: Valium 10 mg PO at 10:00 am) A stat order signifies that a single dose is to be administered immediately and only one. (Example: Give Apresoline 10 mg IM stat)

To prevent hematologic toxicity (platelet levels are decreased) salicylates, NSAIDs, phenytoin, tetracycline and chlorampenicol should be avoided. Examples of NSAIDs are aspirin, indomethacin (Indocin), ibuprofen (Motrin), naproxen (Naprosyn), piroxicam (Feldene), and nabumetone (Relafen). Allopurinol is used to decrease uric acid in Methotrexate therapy. Leocovorin is given for Methotrexate overdose. Vincristine is an anti-cancer drug used alone or with other antineoplastics (e.g. Methotrexate) in treating cancer/leukemia.

Caffeine may decrease the efficacy of the drug. Alcohol use during Methotrexate therapy increases the hepatotoxic potential but it does not decrease the efficacy of the drug. Milk and water has nothing to do with the absorption of the drug.

Adverse reactions 1. Dehydration 2. Intracranial bleeding 3. Headache 4. Blurred vision 5. Nausea and vomiting 6. Volume expansion 7. Chest pain 8. Pulmonary edema 9. Thirst 10. Tachycardia 11. Hypokalemia

Subscription – directions about the number of tablets or amount to be dispersed that is given to the pharmacist. Superscription – client’s name, address and age. The symbol of take thou is also located here. Inscription – contains the drug name, strength and dose.

Trophoblastic neoplasm (choriocarcinoma, Lymphosarcoma) is an indication of giving Methotrexate. Extra precautions in administering Methotrexate should be observed in the following conditions: • Preexisting liver damage or impaired hepatic function Methotrexate may be hepatotoxic. Even without previous signs of GI or hematologic toxicity such as liver atrophy, necrosis and cirrhosis. Special caution should be observed in clients with preexisting liver damage or impaired hepatic function. • Presence of infection, peptic ulcer, ulcerative colitis, geriatric patients or patients with chronic debilitating illnesses. This drug has an immunosuppressive action. Thus, extreme caution should be observed in patients where immune responses may be vital for healing from a certain disease. • Impaired renal function