Olaparib is a drug that is often used to deal with precise types of cancer, which include ovarian and breast cancers. Here's an in-depth description of Olaparib, which includes its applications, benefits, and potential unfavourable effects:

Uses:

Ovarian Cancer: Olaparib is approved for the maintenance treatment of adult patients with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who have responded completely or partially to first-line platinum-based chemotherapy.

Breast Cancer: Olaparib is also used to treat individuals with HER2-negative metastatic breast cancer who have inherited BRCA1 or BRCA2 mutations and have previously received chemotherapy.

Benefits:

1. Targeted Therapy: Olaparib belongs to a family of drugs called poly (ADP-ribose) polymerase (PARP) inhibitors, which target particular enzymes involved in DNA repair. Olaparib inhibits these enzymes, preventing cancer cells from fixing damaged DNA, and resulting in their demise.

2. Maintenance Therapy: Olaparib can be used as maintenance treatment in individuals with ovarian cancer who have responded to platinum-based chemotherapy. 

3. Improved Survival: Clinical trials have demonstrated that Olaparib medication can enhance progression-free survival and overall survival in patients with ovarian and breast cancer, particularly those with BRCA mutations. 

4. Quality of Life: Olaparib, which delays disease progression and reduces the need for more chemotherapy, can enhance the quality of life for patients with advanced cancer.

Side Effects:

While Olaparib can be used to treat cancer, it may potentially produce negative effects. Some frequent side effects are:

1. Nausea and Vomiting: Nausea and vomiting are frequent adverse effects of Olaparib medication, especially in the first few weeks. 

2. Fatigue: Patients who use Olaparib frequently report feeling weary or weak. 

3. Anaemia: Olaparib can cause a drop in red blood cell count, leading to anaemia and symptoms including weariness, weakness, and shortness of breath.

4. Decreased Appetite: Some people may notice a decrease in appetite or changes in taste perception when taking Olaparib. 

5. Diarrhoea: Diarrhoea is a typical gastrointestinal adverse effect linked with Olaparib therapy. 

6. Headache: Olaparib's adverse effects may include headaches and migraines. 

7. Muscle Pain: Some people may have muscular discomfort or weakness while on Olaparib.

8. Increased Risk of Infection: Olaparib may reduce the bone marrow's ability to create white blood cells, raising the risk of infection.