Stamlo Beta is combination product that contains atenolol and amlodipine; hence it is a Fixed-Dose Combination (FDC). In general FDCs should not be used for the following reasons:
Fixed-Dose Combinations (FDCs): Medicines are discovered individually and are supposed to be taken separately. A huge number of irrational, illegal combinations of drugs are being sold in India; quite a few without mandatory approval of the Drugs Controller General, India (DCGI). Except in a few cases (such as TB medicines), it is always better to take medicines separately so that dosage can be adjusted and side effects monitored.
In your case the side effects of atenolol and amlodipine are getting added up.
Amlodipine can cause giddiness and tiredness, and fatigue (exhaustion). It can also cause nocturia (passing of urine at night), increased frequency of passing urine and other urine-related disorders.
Atenol can cause tiredness (fatigue) and giddiness (vertigo).
Secondly technically you are potentially at risk of developing diabetes because of your close family history. Under such circumstances, atenolol is not permitted to be given to you because it increases the risk of diabetes.
Thirdly, in the past couple of years, the treatment of high blood pressure has undergone sea change. Now as per globally accepted guidelines in patients below the age of 55 years, the first choice initial therapy should be an ACE inhibitor such as enalapril (sold under the trade name of BQL - 5-10mg 1-2 times daily). If two drugs are required, then add a diuretic such as indapamide (sold under the trade name of Indicontin Continus - one tablet in the morning daily).