Oncology Lecture.ppt

ONCOLOGY AND PAIN MANAGEMENT WITH AN OCCUPATIONAL THERAPY

FOCUSJennifer Beall, Pharm.D.Assistant Professor, McWhorter School of PharmacySamford University

Objectives

Describe and apply the basic principles of pharmacology to the drugs discussed

Identify the implications for occupational therapy evaluation and treatment

Describe the disease process of osteosarcoma, its treatment, and their impact on occupational therapy evaluation and treatment.

CHEMOTHERAPY: BACKGROUND

Most chemotherapy agents work by stopping growth of or killing cancer cells.

Biological process involved include cell cycle, RNA and DNA synthesis.

Newer cancer treatments attack cells from different ways: cutting off blood supply, identifying cancer cell as foreign, etc.

CHEMOTHERAPY: CELL CYCLE

G0: resting phase G1: pre-DNA synthesis S: DNA synthesis G2: post-DNA synthesis M: mitosis (actual cell division) Some chemotherapy drugs are cell-cycle-

specific

CHEMOTHERAPY: CONCEPTS

Growth fraction: percent of dividing cells related to total population of cancer cells

Total cell kill: every tumor cell that is able to divide must be killed to eliminate the cancer

Other factors also affect a cell’s response to chemo: tumor-cell heterogeneity, drug resistance, dose intensity and patient-specific factors.

CHEMOTHERAPY: SIDE EFFECTS

Most common: bone marrow toxicity, GI upset, alopecia

Some adverse effects are due to attack of rapidly-dividing cells

Neurotoxicity possible with several drugs (see appendix)

CHEMOTHERAPY: CATEGORIES

Alkylating Agents Antimetabolites Antibiotics Plant Alkaloids Hormones Heavy Metal Compounds Miscellaneous Agents

OSTEOSARCOMA

Osteosarcoma is cancer of bone that occurs mainly in adolescents and young adults

Surgery alone is not enough; patients will likely need chemotherapy

The site of the tumor can determine prognosis

Source:http://www.cancer.gov/cancerinfo/pdq/treatment/osteosarcoma/healthprofessional/#Section_1

OSTEOSARCOMA (Cont’d)

Chemotherapy regimens use methotrexate, doxorubicin, cyclophosphamide, cisplatin, ifosfamide, etoposide and carboplatin

Surgery and radiation therapy can also be used

ANALGESIA: BACKGROUND

Physiology of pain: – Stimulus activates nociceptors, which translates

stimulus into an electrical signal– Electrical signal is sent along the nerves to the

spinal cord– Pain is regulated in the CNS by opioid receptors

ANALGESIA: TREATMENT

WHO Analgesic ladder Non-opioids include acetaminophen

(Tylenol®), NSAIDs, COX-2 inhibitors Combination products include Darvocet,

Lortab, Vioden, Vicoprofen, Percocet Opioids include morphine, meperidine,

codeine, oxycodone, hydrocodone

ANALGESICS: NSAIDs

Mechanism of action: inhibits cyclooxygenase, which stops prostaglandin and thromboxane synthesis

Role of prostaglandins: ranges from vasodilation or –constriction, involved in inflammatory response, help produce fever, involved in dysmenorrhea

Role of thromboxane: blood clotting

ANALGESICS: NSAIDs

COX-1 vs. COX-2: – COX-1 is found in stomach mucosa, kidneys– Role of COX-1: helps protect stomach lining from

gastric acid; helps maintain renal function; helps regulate normal platelet activity

– COX-2 is produced by cells when they are injured– Role of COX-2: helps produce prostaglandins to

respond to pain and inflammation

ANALGESICS: USES OF NSAIDs

Treatment of pain / inflammation: these drugs are used for mild-moderate pain (i.e. muscle aches, arthritis, dysmenorrhea, post-surgical pain)

Treatment of fever: ibuprofen is most common; aspirin should NOT be used in children with fever

ANALGESICS: USES OF NSAIDs

Treatment of vascular disorders: aspirin is commonly used for its inhibition of platelet aggregation to prevent MI or stroke

Prevention of cancer: aspirin use may decrease risk of colon cancer; COX-2 inhibitors are being studied in preventing various types of cancer (skin, breast, colon)

ANALGESICS: NSAID SIDE EFFECTS

GI problems:– Ranges from discomfort to ulceration – May be prevented by using buffered or enteric-

coated formulations

Kidney problems– Especially in those with renal dysfunction or the

elderly

ANALGESICS: NSAID SIDE EFFECTS

Allergic-type reactions– Rare; produces bronchospasm, urticaria

Overdose– Aspirin: symptoms range from tinnitus to

metabolic acidosis– Acetaminophen: can result in liver failure

ANALGESICS: COX-2 INHIBITORS

Products on market: celecoxib (Celebrex®), rofecoxib (Vioxx®), meloxicam (Mobic®), valdecoxib (Bextra®)

Selective for COX-2 enzyme to reduce effects to GI tract, kidneys

May still cause GI side effects (diarrhea, heartburn); may increase risk of upper respiratory tract infections

ANALGESICS: ACETAMINOPHEN

Mechanism of action unknown; possibly via prostaglandin inhibition

Is analgesic and antipyretic; is not anti-inflammatory or anticoagulant

May be toxic to liver, especially when used with alcohol

ANALGESICS: OPIOIDS

“Opioid” vs. “narcotic” Endogenous opioid receptors:

– Mu: causes sedation, respiratory depression, constipation

– Kappa: causes sedation, psychotic effects, constipation

– Delta: inhibits dopamine release

ANALGESICS: OPIOIDS

Agonists: acts primarily at mu receptors

Agonist-antagonists: act as agonists at one type of receptor yet acts as antagonist at other types

Antagonists: block opioid receptors

ANALGESICS: OPIOIDS

Mechanism of action: inhibition of transmission of the electrical signal across the synapse.

Opioid receptors are located on pre-and post-synaptic neurons

Decreases neurotransmitter release from presynaptic neuron; decreases excitability of postsynaptic neuron

ANALGESICS: OPIOIDS

Clinical applications:– Used mostly for severe and chronic pain– Strengths: no maximum dose, effective, available

in several dosage forms (including PCA)– Weaknesses: side effects (sedation, constipation,

respiratory depression), potential for abuse and addiction

ANALGESICS: OPIOIDS

Addiction: psychological dependence, seen as continued need for drug for effects other than pain relief

Tolerance: a larger dose is required to maintain the original effect

Physical dependence: patient experience withdrawal symptoms if drug is suddenly discontinued

CONCLUSION: SPECIAL CONCERNS FOR REHABILITATION PATIENTS

Chemotherapy:– Drugs that can cause neurotoxic effects– Cancers that affect bone, or nervous system

Analgesia:– Drugs used to treat disorders requiring

rehabilitation– Side effects of opioids (i.e. sedation, dizziness)

that require special handling of patients

QUESTIONS?