Brief Answer:
No atenolol, rest management explained

Detailed Answer:
Thank you for asking!
I understand the trouble with posture intolerance and associated with tachycardia, headache, palpitation, sweating, nausea and near syncope with any posture change from sitting to standing.Now the management depends on the type, whether primary or secondary, and there are non-pharmacological and pharmacological options we all are gonna discuss that.
Here is complete description of what pots is .POTS is defined as orthostatic intolerance associated with tachycardia exceeding 120 beats per minute or an increase in the heart rate of 30 beats per minute from baseline within 10 minutes of changing the posture from a lying to standing position, in the absence of long-term chronic diseases and medications that affect the autonomic or vascular tone. There is no drop in blood pressure; it may even rise in the upright posture. Patients experience symptoms such as headache, nausea, tremors, sweating, palpitation and near syncope.
failure of peripheral vascular resistance to increase sufficiently in response to orthostatic stress, and, consequently, venous pooling occurs in the legs resulting in decreased venous return to the heart. This is compensated for by an increase in heart rate and inotropy.
The most common primary form of POTS is called the 'partial dysautonomic' form and i believe you have this type.
POTS is mostly followed by viral infections, trauma, surgery and after pregnancy.
Lets discuss the management.
1)If you are using any of the following medicines then abruptly discontinue them.
You are using atenolol and that itself causes and worsens POTS so discontinue it and start a more friendly antihypertensive.
Alpha blockers
Beta blockers
Gangion-blocking agents
Angiotensin-converting enzyme (ACE) inhibitors
Calcium channel blockers
Nitrates
Diuretics
Monoamine oxidase inhibitors
Tricyclic antidepressants
Phenothiazines
Ethanol
Opiates
Sildenafil citrate
2)Avoid Dehydration, take plenty of fluids.At least two litres a day.
3)Avoid alcohol
4)Keep salt intake to (3–5 grams/day)
5)Do Aerobic exercise of the lower extremities to augment the skeletal muscle pumps , it will help.
6)Use compression hose extending up to the waist.
7)Discuss the following meds with your doctor and let them decide what is best for you.
Exercise
Erythropoletin
Hydration + increase salt intake
Octerotide
Fludrocortisone
Labetalol
Midodrine
Clonidine
Methylphenidate
Bupropion
Selective serotonin reuptake inhibitor (SSRI)/Serotonin and noradrenaline reuptake inhibitor (SNRI)
Get in touch with your neurologist to sort out the type of the POTS with some work up like Hyperadrenergic pots, or secondary due to a cause. If you are young and have a POTS after some trauma like surgery or viral infection or pregnancy then it will resolve in 2 to 5 years maximum. If it comes up to be hyperadrenergic then you may need lifelong treatment.Get to your neurologist and stay in touch with them.Let them decide what is best for you.
Take good care and dont forget to close the discussion please.
May the odds be ever in your favour.
Regards
S Khan

---

Brief Answer:
Labetalol with many other medicine

Detailed Answer:
Thank you for getting back to me!
labetalol is advised and recommended for the POTS. Use clonidine and midodrine and other medicines i mentioned in my previous answer to help the tachycardia. No other beta blocker than labetalol are advised.
Take care

---